.i5?5(A yt^^yr-^^ THE UNIVERSITY OP ARIZONA Agricultural Experiment Station VOLUME VIII of the Arizona AgTieultnral Experiment Station Publications consisting of BULLETINS 77-84 ANNUAL REPORTS 1916-1917 AND TIMELY HINTS FOR FARMERS 111-335 Tucson, Arizona, 1915-1918 M- University of Arizona Agricultural Experiment Station Bulletin No. 77 A group of Smyrna (Calimyrna) figs. Practical Fig Culture in Arizona By W. H. Lawrence Tucson, Arizona, June 1, 1916 UNIVERSITY OF ARIZONA AGRICULTURAL EXPERIMENT STATION GOVERNING BOARD (Regents of the University) Ex-Offlcio Hon. George W. P. Hunt Governor of the State Hon. Charles O. Case, Supt. Pub. Instruction. Appointed by the Governor of the State Frank H. Hereford, Chancellor William V. Whitmore, A. M., M. D Treasurer William J. Bryan, Jr., A. B., Secretary Lewis D. Ricketts, Ph. D., Regent William Scarlett, A. B., B. D., Regent Roderick D. Kennedy, M. D., Regent Rudolph Rasmessen, Regent Frank J. Duffy, Regent RuFus B. von KleinSmid, A. M. Sc. D. . President of the University AGRICULTURAL STAFF Robert H. Forbes, M. S., Ph. D., . . . . . . . Director John J. Thornber, A. M. Botanist Albert E. Vinson, Ph. D., . Biochemist Clifford N. Catlin, A. M. Assistant Chemist George E. P. Smith, C. E., Irrigation Engineer Arthur L. Enger, B. S., Assistant Engineer George F. Freeman, B. S Plant Breeder J. C. Th. Uphof, Assistant Plant Breeder Stephen B. Johnson, B. S., Richard H. Williams, Ph. D. Walter S. Cunningham, B. S Austin W. Morrill, Ph. D., Stanley F. Morse, B. A. S., George W. Barnes, B. S. A., L. S. Parke, B. S., Edith C. Salisbury, . EsTMER W. Hudson, Assistant Horticulturist Animal Husbandman Assistant Animal Husbandman Entomologist . Superintendent Extension Service Livestock Specialist, Extension Service . Boys and Girls State Club Agent Home Economics Specialist Egyptian Cotton Specialist James A. Armstrong, B. S., . . . Farm Adviser, Maricopa County Arthur L. Paschall, B. Agr., Farm Adviser, Cochise-Santa Cruz Counties Charles R. Filleruf, B. P. I., D. B., Farm Adviser, Navajo-Apache Counties Alando B. Ballantyne, B. S., Farm Adviser, Graham-Greenlee Counties Foster T. Parker, . . . . . Secretary, Extension Department Helen M. A. Miller, . . Secretary, Agricultural Experiment Station Hester L. Hunter, Stenographer The Experiment Station offices and laboratories are located in the University buildings at Tucson. The range reserves (cooperative, U. S. D. A.), are suit- ably situated adjacent to and southeast of Tucson. The work in horticulture and animal husbandry has been conducted mainly on the Experiment Station Farm, three miles northwest of Phoenix, Arizona. The date palm orchards are three miles south of Tempe (cooperative ,U. S. D. A.), and one mile southeast of Yuma, Arizona, respectively. The experimental dry-farms are near Cochise, Snowflake, and Prescott, Arizona. Visitors are cordially invited, and correspondence receives careful attention. The Bulletins, Timely Hints, and Reports of this Station will be sent free to all who apply. Kindly notify us of errors or changes in address, and send in the names of your neighbors, especially recent arrivals, who may find our publications useful. Address. THE EXPERIMENT STATION, Tucson, Arizona. CONTENTS Introduction 1 Reasons why fig planting should be increased 2 Character of fig producing sections 2 Temperatures 3 Precipitation 4 General field survey 6 Scop'e of fig growing 9 Investigations in Salt River Valley 11 Influence of temperature 13 Yield of edible fruit 17 Decrease in size of fruit during picking season 19 Size of fruit in different crops 20 Yield of Capri figs 20 Results of the survey and investigation 22 The fig plant " ■ 22 Groups of figs 23 The fruit of the fig 24 Kinds of flowers 24 Crops of fruit 25 Classification of figs 26 New type of fig 27 Characteristics of varieties • 27 Fig culture 30 Climatic requirements 30 Soil • • 30 Selecting varieties 31 Propagation of the fig 32 Propagation by seeds 32 Selecting stock for propagation 32 Vegetative propagation 34 Propagation by shoots 34 Arrangement of varieties in the orchard 35 Edib e figs 35 Capri orchard 35 Assortment of Capri trees 35 The proportion of Capri trees 35 Providing winter protection 36 Planting and care of the young orchard 36 The pruning of bearing trees 37 Cultivation and irrigation 37 Winter protection for fig trees 38 Caprification 38 Plants requiring caprification 38 Methods of caprification 39 How caprification is accomplished 39 Life history of the wasp 40 Emergence of blastophaga 40 Splitting and souring of the fruit 41 Pests 42 Acknowledgments 42 ILLUSTRATIONS PLATES Plate I. A young but healthy fig orchard Frontispiece FIGURES Fig. 1. Diagram showing monthly distribution of rainfall at Yuma, Parker, and Phoenix, Arizona 6 Fig. 2. Results of the 1912-1913 freeze 7 Fig. 3. View showing last 40 trees in rows A and B, Fig. 2 8 Fig. 4. View of third section of 20 trees, rows A and B, Fig. 2 13 Fig. 6. Sections of fruit of Capri No. 1 21 Fig. 6. Side, apical, longitudinal, and cross section views of Capri figs. . . 23 Fig. 7. Adriatic type of fig 25 Fig. 8. External and cross section views of the Smyrna fig 26 Fig. 9. Group of black Smyrna figs 28 Fig. 10. Group of well matured white Adriatic figs 29 Fig. 11. Group of well matured Black Mission figs 31 Fig. 12. Terminal branch from Capri No. 1 33 Fig. 13. Smyrna figs split open before reaching maturity 40 Fig. 14. Dorsal and ventral views of June bug 41 Practical Fig Culture in Arizona By W. H. Laurence INTRODUCTION The importance of the fig as a fruit crop in Arizona is shown by its presence in nearly all localities in which it will endure the winters and survive the frosts of spring. In addition to being a valuable fruit it serves as an excellent shade tree. The fig is a food fruit. Containing an average of more than 50 per cent sugar and 3.5 per cent protein, it is probably the most valuable of all dried food fruits, of which the fig, apple, peach, raisin, and date are the most common. The dried fig has a mildly laxative action and is not injurious when eaten in large quantities. At the close of a study pursued during two consecutive years, the writer was impressed with the following facts: (a) A proper selection of varieties will make fig culture possible in a wide range of cliniatic, water, and soil conditions such as cover a large propor- tion of the agricultural area of the State. (6) Where limiting factors of production are almost nil and commercial production is possible, economic methods are not practiced in the growing or the distribution of the fruit on local and distant markets, (c) Few people appreciate the food value of the fruit and its many possible uses in either a fresh or a preserved condition. This publication brings together the results of a general field survey, conducted by the writer in person and by correspondence, to determine the general distribution of the plant, to locate the hardy forms that have survived through a decade or more of planting, to determine the number of groups represented and the cultural management required. It also includes the results of a study pursued for three consecutive seasons on 60 trees representing a total of 43 horticultural forms belonging to 5 botanical varieties. This study was made primarily to determine the most desirable forms and varieties to be propagated and disseminated for the purpose of producing larger and more uniform yields of fruit for home use and for the market. The results of this study are given in 2 Bulletin 77 detail as experiments and observations, or appear as discussions and recommendations necessary to the intelligent propagation and economic management of the fig. REASONS WHY FIG PLANTING SHOULD BE INCREASED Arizona has a population of approximately two persons per square mile of territory! A large proportion of these live in towns and villages located many miles apart. Rural population outside the highly developed irrigated areas is scattered, usually as isolated families on ranches. Means of communication are, moreover, limited, except along the main-line railroads. With a fair proportion of the people widely scattered and for the most part long distant from shipping centers, the distribution of food products becomes an important problem. In many cases the method of transportation and distribution prohibits the handling of perishable products. This usually means a limited diet, for the greater portion of the year at least. In the absence of an adequate supply of fresh fruit during the season in which this kind of fruit should be used, the writer is convinced of the value of a study that may lead to a wider dissemination of the fig plant and to an in- creased use of its fruit both in a fresh and preserved condition. CHARACTER OF FIG-PRODUCING SECTIONS The greater portion of southeastern Arizona is comparatively low in elevation, with nearly parallel mountains extending north- west to southeast, ranging in height from 1,000 to 3,000 feet and separating comparatively level valleys lying between them. The soil of these valleys has been built up of alluvial deposits from the eroded mountains and is very fertile. The lower parts of this terri- tory are the areas along the Colorado and Gila Rivers. In the broad valleys, low-lying mesas and their prolongations into the higher elevations of the southeastern and south central portions of the State, irrigation has made it possible to build a veritable paradise. The character of the soils and the application of water provide conditions suitable for the successful growth of many temperate and subtropical horticultural plants. The eastern and more northern portions of the State form plateaus ranging in elevation from 4,000 to 6,000 feet, and in the northern part some of the mountains are much higher. The varied topography induces perhaps the greatest diversity in climate of any State. Over the lower elevations intense heat Practical Fig Culture in Arizona prevails, little precipitation occurs, sunshine is almost continuous, and the relative humidity is very low. Temperatures.— Over the low elevations, which are confined mainly to the southwestern portion of the State, and which include the valleys of the lower Colorado and lower Gila rivers, the climate is arid and the range of temperature between day and night is con- siderable. The heat of summer is torrid, frequently rising above 100° F. and at rare intervals to as much as 120° F. in the shade. Over the lower portions of this area the temperature seldom reaches the freezing point and frosts are rare. At higher elevations, and especially in the plateau sections where air drainage is restricted, the clear sky intensifies radiation and the temperatures of spring frequently drop below the freezing point. At extreme elevations the temperat^ire may fall below zero. The following data are introduced in order to show the varia- tions that occur from season to season or during a single season. TABLE I. — MEAN, LOWEST, AND HIGHEST TEMPERATURES; EARLIEST DATE OF KILLING FROST IN AUTUMN AND LATEST IN SPRING; YEAR, AND RANGE. OF DAYS IN GROWING SEASON IN EIGHTEEN WIDELY SCATTERED SECTIONS IN WHICH FIG TREES PRODUCE CROPS. • Length of growing season Highest temper- Lowest temper-! Mean temper- Earliest killing Latest killing Station Min. Max. ature ature \ ature frost frost ! Year no. of days Year no. of days Aztec 125 15 72.8 Nov. 17 Mar. 12 1909 254 1900 364 Mohawk.. . 126 22 75.4 Dec. 5 Feb. 14 1908 1 308 1904 366 Parker. . . . 127 9 70.4 . Oct. 26 Apr. 6 1897 223 1901 310 Yuma Buckeye.. . 120 121 22 11 72 1 all 365 all 365 67-7 Oct. 22 Apr. 6 1906 203 1910 307 Gila Bend. 120 11 71.5 Nov. 16 Mar. 13 1899 227 1907 34V Phoenix. . . 117 16 69.7 Nov. 9 Mar. 31 1897 222 1901 335 Mesa 119 9 68.6 Oct. 21 Apr. 2 1906 202 1900 317 Tempe. . . . 119 12 68.2 Oct. 23 Mar. 3 1910 308 1906 334 Tombstone 107 9 62.3 Oct. 22 Apr. 12 1906 235 1910 305 Nogales. . . 110 10 62.0 Oct. 15 May 19 1902 189 1903 241 Willcox 110 2 59.0 Oct. 15 May 27 1906 166 1901 2b3 Huachuca.. 105 0 60.9 Oct. 17 May 9 1908 186 1903 279 Bisbee .. . . 101 8 60.0 Oct. 22 Apr. 30 1893 152 1910 306 Casa Grande 115 8 68.4 Oct. 8 Apr. 5 1906 189 1910 31b Maricopa. . 126 8 69.6 Oct. 22 Apr. 4 1909 240 1900 321 Thatcher. . 113 9 62.6 Oct. 6 May 7 1909 155 1906 207 Tucson. . . . 112 6 66.7 Oct. 19 Apr. 18 1897 208 1893 306 4 Bulletin 77 A study of the data shows the mean temperature to range from 59.0° at Willcox to 75.4° at Mohawk, the lowest temperature to range from 0° F. to 22° F.; the highest temperature to range from 101° F. to 127° F., with a general average of approximately- Ill" F.; the earliest date of killing frost in autumn to vary from October 6 at Thatcher to December 5 at Mohawk; general killing frosts rarely if ever occur except in the valley lands; the latest frost in spring varies from February 14 at Mohawk to May 27 at Will- cox; and the length of the growing season varies at each station with wide ranges in duration of growing season at the same stations in different years. Considering temperature as a limiting factor, the data in Table I show the Lower Colorado Valley and mesa country and the Salt River Valley to be quite free from dangerous temperatures; and for most years the growing seasons, measured in the number of days from the last killing frost in spring to the first killing frost in autumn, are phenomenally long. Within these areas are many thousands of acres of land well adapted to fig culture, being not only frostless but nearly rainless. Throughout these areas the Smyrna fig, when caprified, should produce satisfactory returns in most seasons. Throughout the higher elevations where the climate is more severe, with the possible exception of a few small isolated areas, the Adriatic type is the more desirable form. Precipitation. — ^Precipitation occurs principally during two por- tions of the year, a summer maximum during July to vSeptember and a secondary maximum during the colder portion of the year. During April, May, and June the area is practically rainless and but little occurs during the late autumn months. In the eastern half of the State the rainfall varies from 10 to 25 inches per year, while in the western section precipitation varies from 1 to 10 inches. Rainfall increases with the elevation. The character of the pre- cipitation, the time of occurrence, the distribution during the several periods of the year, the amount each month, and the varying periods of heavy and light precipitation are questions of vital im- portance in the production of the fig. The following data compiled from various sources show the character of the precipitation occur- ring at several places in the State where the fig is being grown. Practical Fig Culture in Arizona 5 TABLE II. — LOCATION, ELEVATION, LENGTH OF RECORD, MEAN ANNUAL PRECIHTATION, AND RANGE OE VARIATION FROM LOWEST TO HIGHEST, AND THE YEAR IN WHICH THE EXTREMES OCCURRED FOR TWENTY WEATHER BUREAU STATIONS. oil? Rani;e of variation Eleva- 1 Mean Station 1 annual tion rt >> Highest 1 Next highest Lowest precipi- (feet) tation (inches) y Year Inches Year Inches Year Inches Aztec 492 12 1905 13.57 1908 7.55 1901 1.12 4.35 Mohawk.. . 538 6 1905 6.49 1886 4.13 1895 0.10 3.17 Parker 353 19 1905 9.58 1912 6.55 1900 2.09 4.83 Yuma 141 35 1905 11.41 1909 8.63 1899 0.60 3.26 Buckeye.. . 980 23 1905 i 21.80 1896 9.50 1891 0.63 7.22 Gila Bend. 737 12 1896 10.21 1908 7.69 1900 2.55 5.67 Phoenix. . . 1,108 20 1905 19.73 1911 14.12 1885 3.77 7.39 Mesa 1,244 19 1905 20.31 1911 13.82 1900 5.10 9.10 Tempe. . . . 1,165 11 , 1905 22.15 1911 14.45 1910 6.02 11.01 Benson. . . . 5,532 12 1905 22.58 1896 16.78 1885 4.24 9.35 Tombstone 4,550 17 1905 27.84 1907 19.31 1910 11.77 14.54 Cochise.. . . 4,250 7 1905 22.27 1896 16.03 1900 1.30 11.41 Willcox... . 4,205 12 1905 23.52 1884 18.38 1897 5.66 10.67 Huachuca.. 5,100 30 1905 36.97 1907 16.96 1910 9.54 16.86 Bisbee 3,523 20 1898 25.87 1907 23.59 1910 12.85 18.05 Clifton 3,584 6 1898 16.14 1910 8.67 13.16 Casa Grande 1,396 1905 19.52 1899 1 10.21 1885 2.02 6.06 Maricopa. . 1,180 13 1905 13.51 1912 8.89 1882 0.38 6.06 Thatcher. . 2,800 17 1905 17.38 1913 12.83 1902 4.73 10.08 Tucson. . . . 2,425 30 1905 24.17 1889 18.37 1885 5.26 11.58 Since nearly ripe fruit is usually ruined by moisture, no rainfall and dry air are desirable during the ripening and picking season. A glance at the above data shows that the annual rainfall varies greatly for each section and that occasional extremely wet seasons occur. Seasonal distribution of rainfall is the important factor in fig production. The normal annual rainfall chart appearing below, is useful in giving correct information concerning the usual distri- bution and precipitation for sections in which the Smyrna and less hardy forms may be grown. In those sections where Adriatic forms are adaptable for home use occasional summer rain does no appreciable injury, since immediate attention is given to th' collection and use of the fruit. At higher elevations where the summer rainfall is considerable, Bulletin 77 neglected plantings of a decade or so still survive and produce some fruit without care. In such localities a greater use of the fig would be possible if it were given attention and protection. GENERAL FIELD vSURVEY Through coirespondence and a personal general field survey, the approximate distribution of fig trees now growing throughout the State has been determined, as follows* In Nogales there are several small trees of a black variety that bear one crop each year. At Garces there are several large, fine trees of the so-calhd small Yuma Parker Phoenix lliliULLIiliXili ■■LLUJIililiil Fig. 1. — -Diagram showing the comparative monthly distribut-'on of rainfall in fractions oijan inch, for Yuma and Parker, located in the southwestern lowlands, and Phoenix, j in the middle section, embracing the Salt River and Gila River Valleys. Black Mission. Brown Turkey is also being tested. In this imme- diate locality the more or less protected places in the foothills and mountains, where air drainage is good, provide the best situations for fig growing. At Roosevelt there are four small trees, five to six years old. These produce green truit throughout the season, but the crop falls before it ripens. They are probably Smyrna trees. At Tucson the Brown Turkey produces one good crop each year, ripening the fruit for approximately 40 days, during July and August. Both black and white forms of the Adriatic group, also quite common in this section, are less important. Winter weather severe enough to kill the younger growth, less frequently the entire top, occurs, yet pruning away the dead stems allows new wood to form on which a fair second crop of fruit may develop. "Practical Fig Culture in Arizona 7 There is a small home-garden fig orchard at Hackberry on the Colorado River (Gregg's Ferr}^- In the Gila River Valley at vSolomonville and Thatcher both Tvhite and black fig tress are found. These plants range up to 30 years in age and bear two to three crops each year. The black variety is»perhaps the more desirable since it produces fruit through a longer season of the year. In Clifton and adjacent territory both black and white figs are grown. Even at this elevation ^3,584 feet), two and occisionally three crops are produced, maturing over a period of 40 to 60 days, the first ripening early in August. Smyrna trees are also reported growing in Clifton. Well matured, locally grown figs are sold at 12 cents a pound wholesale. Fig. 2.— Results of the 1912-1913 freeze. View of the 60 trees planted in two rows on the Experiment Station Farm near Phoenix. Attention i s called to the fact that the 30 trees located in row B were killed to the ground and but few of them have partially recovered. The row has the appearance of sticks set in the ground. Attention is also called to the presence of two specimens barely alive in row A while there are several large kealthy plants. Photograph by W. H. Lawrence. At an elevation of 5,000 feet in the Dragoon Mountains, both black and white figs produce two and three crops annually, the ripening period continuing from July to November, while frosts destroy the fruit at lower elevations where air drainage is restricted. Fig trees of a white variety, very old but thrifty and large, are also located in the Huachuca Mountains at elevations up to 5,000 feet. Stock from this variety has passed the winter successfully in the Sonoita Valley without protection, where even more severe winter weather occurs. In the Sonoita Valley there are also black and white fig trees several years old which produce fair crops. 8 Bulletin 77 Throughout the Sulphur Spring Valley the Mission and White Adriatic are the leading varieties. Old trees bear two crops each year, ripening until the advent of freezing weather. A p^irple fig grown and distributed from Safford also comes in two crops, ripening until the green fruit is destroyed by frost. A fine tree of the black variety is also reported from Tombstone. vSmyrna figs have been planted at Gleeson, and while they endure the winter and set fruit, none matures due to lack of pollination. A small white \'iriety about 10 years of age, located near Willcox, now bears two to three crops each year, producing almost continuously from the last frost in spring to the first frost in autumn. Several large fig trees ire standing in the streets of Bisbee. Fig. .3. — View showing last 40 trees in rows A and B, Fig. 2. Note the poor condition of the trees In row B, also the vacant spaces; and the three weak trees in row A with a second group of healthy plants in the distance. In the Lower Verde River country, at an altitude of 3,315 feet, a small white fig endures the winter, while a black variety grown in the same location freezes to the ground. Two crops are produced each year. Along the Upper Verde River, Angelique (white), San Pedro and Mission (black) bear annually, but usually both the earliest and latest figs of the first and last crops are destroyed by frosts The white variety endures the conditions up to 4,500 feet eleva. tion, while the black sorts .prove less hardy. With protection, plants are easily carried through the winter, even at an elevation of 5,800 feet. Practical Fig Culture in Arizona 9 The production of figs in both the valley and the mesa country near Yuma is limited to a few varieties of Adriatics. These include both light and dark-colored forms. Most of the plantings are old. The names of the varieties, dates of planting, and sources of stock have been lost through the exchange and sale of property. In both mesa and valley the fig believed to be the Black Mission is the leading sort, since it excels in carrying capacity, which makes it possible to ship the fruit long distances. Two crops are produced. The tree should bear commercial crops at 4 to 6 years of age. On the mesa, the first ripens 8 to 12 days earlier than on the valley floor, where picking begins May 20 to 25. The crop is in demand as fresh fruit in Los Angeles and San Francisco markets at prices ranging from 50 to 75 cents per pound. By the time the first fruit produced in the valley is ready for shipment, however, the price usually drops to 12 to 20 cents in these distributing centers. This fruit is shipped in 7-pound crates. A yield of 5 to 20 crates is secured per tree. The second crop begins to ripen July 7 to 12 and continues for about three weeks. The fruit is put up in two grades, selling at about 9 cents and 5 cents, respectively. On trees 10 to 15 years of age, the yield varies from 10 to 35 crates. Of the other varieties mentioned, both light and dark-colored, several are larger then the Mission but are too soft to ship, yet even these are of great value for canning or drying. Fig trees grown in this section of the State are mostly located along ditch banks, and receive no cultivation or irrigation, yet return enormous profits. At Mesa, in the Salt River Valley, occurs the so-called Black Adriatic, which is the sole representative of commercial sorts grown in the immediate locality. This variety produces two crops, the first ripening about June 10. It is shipped to various markets — San Francisco, Denver, El Paso, and intermediate points. The grower receives 4 cents per pound. The second crop ripens July 25 to August 1. For the most part it is consumed locally for canning, selling as fresh fruit at 2 cents per pound. Trees grow without care along banks of irrigation canals. On the Experiment Station Farm near Phoenix is a small orchard of approximately 60 trees of various varieties. Half the orchard was planted in 1904 and the balance in 1909. Details concerning these trees are given elsewhere in this paper. SCOPE OF FIG growing Figs, no doubt, have been grown in Arizona for more than a hundred years. Numerous forms have been generally disseminated 10 Bulletin 77 throughout the warmer portions of the State. Even the casual observer notes that many varieties find conditions congenial to vegetative growth, while many produce annual yields of well matured fruit. As early as 1899 fig production had become an im- portant line of fruit raising. The Twelfth United States Census shows 4,325 trees of bearing age, and a yield of 949,140 pounds. The Thirteenth Census, however, shows a total of 3,848 trees in bearing, a decrease of nearly 10 per cent, with a much greater decrease in average yield per tree. There are no commercial orchards in the State. Less than 400 farms have bearing trees, the average number of trees per farm being approximately 10. These trees are generally located in the home orchard, the lawn, or along the irrigation ditch. The following data, adapted from the Thirteenth United States Census, is of more than usual interest and is introduced at this point to show clearly the success met with in planting trees at earlier dates, the results secured from older plantings, and the development of fig growing in sections where very promising returns have been realized. TABLE III. — SHOWING THE NUMBER OF BEARING AND NON-BEARING FIG TREES, INCREASE IN PER CENT OF PLANTINGS, TOTAL AND AVERAGE YIELD FOR ALL COUNTIES, 1910. Counties Apache Cochise Coconino. . . Gila Graham . . . . Maricopa. . . Mohave. . . . Navajo Pima Pinal Santa Cruz. Yavapai. . . Yuma The State. Trees bearing Total yield Number 76 37 190 2,628 70 Pounds 785 10,655 3,236 96,540 630 344 164 2 60 277 3,848 650 5,800 200 3,100 5,485 Average yield Trees non- bearing Pounds 10.3 287.9 17.0 36.7 9.0 127,081 1.8 35.4 100.0 51.6 19.8 33.0 Number 215 44,694 58 2,123 Increase in last 10 years Per cent 6.6 113.2 1,700.7 113 70.1 96.6 776.4 47,208 1,226.8 The above table is instructive since it shows that conditions in Apache, Coconino, and Navajo Counties inhibit the growing of the Practical Fig Culture in Arizona 11 fig plant. Also, while older plantings have endured the conditions of climate and soil, increased plantings in Gila, Mohave, Pima, and Santa Cruz Counties have not been successful, yet in some parts of Graham, Maricopa, Pinal, Yavapai, and Yuma counties con- ditions are favorable to production on a commercial scale. It is to be noted that of the four counties in which no young trees are reported, Santa Cruz and Gila counties report average yields of 100 to 287.9 pounds per tree. It is apparent that plantings can be increased through the use of hardy stock. An inspection of the data will show increased plantings of 6.6 per cent to 1,700 per cent for different counties. INVESTIGATIONS IN SALT RIVER VALLEY A major portion of the investigations was conducted in a small orchard of several varieties of figs located on the Experiment Station Farm at Phoenix. There were 60 trees; 30 were planted in 1904, the remainder in 1909. The following table gives data relative to the orchard and its condition at the close of the 1915 growing season. TABLE IV. number OF STANDARDS, HEIGHT AND SPREAD OF TOPS, CONDITION OF THE PLANT, GROWTH OF NEW^ SHOOTS AND SUCK- ERS OF 43 VARIETIES OF FIGS, 1915. Variety Cernica Mission, Black Mission, Black Rose Blanche Bourjassote Panache Magnolia Magnolia Bardajic Capri Milco Capri Milco Capri Milco Capri Milco Capri Milco White Adriatic White Adriatic . . . . Capri No. 1 Capri No. 1 Num- ber of stems 1 1 3 1 2 1 3 1 1 4 4 1 4 2 1 1 1 Height of top Feel 4.5 22 17 11 12 7 8 17 10 10 2 8 8 15 15 16 12 Spread of top Feel 2 30 19 14 7 7 6 22 7 8 3 5 5 23 26 26 15 Condition of plant Growtli new shoots Good Very good. Good Fair Good Very poor. . . Poor Very good. . Good Fair Fair Good Good Good Very good. . Very good. . Very good. . 2.5 12 5 8 30 1 2.5 15 12 10 12 6 5 4 3 8 Average length suckers Inches Inches 12 48 72 6 4 12 Bulletin 77 TABLE IV.-^-NUMBER OP STANDARDS, HEIGHT AND SPREAD OF TOPS, CONDITION OF THE PLANT, GROWTH OF NEW SHOOTS AND SUCK- ERS OF 43 VARIETIES OF FIGS, 1915 — Continued. Variety Capri No. 2 Capri No. 3 Capri No. 3 Capri Magnissalis Capri Magnissalis Capri Magnissalis Maslin Capri No. 143. . Maslin Capri No. 91. . . Capri Elanford Agen White Endich San Pedro White Checker Injir Black Smyrna Black Smyrna Lob Injir Lob Injir Lob Injir Bellona Black Ischia Green Ischia Madeleine Doree Genoa Blue Genoa White Genoa Negro Largo Lemon Royal Vineyard Verdal Longue Angelique. Coldi Signora Nigra. . . Drap d'Or Dauphine Ronde Violette Hative. Ringo Del Mel Hirta du Japon Salmo Sambach Bulletin Smyrna Black Adriatic Black Adriatic Num- ber of stems Height of top 3 3 4 4 3 1 4 3 1 4 3 4 4 6 3 4 1 2 3 1 1 1 Spread of top Feet 10 10 9 5 7 5.5 8 8 8 8 11 14 14 15 15 15 8 11 6 8 8 13 10 7 9 13 7 Feel 11 8 4 10.5 7 9 7 17 32 13 13 8 7 9 3 3 3 Condition of plant Growth .Average new I length shoots I suckers Good . Good. Good. Good. Good. Good. Inches 4 15 6 7 6 8 Inches 6 7 6 6 7 19 19 19 9 9 3 8 4 5 3 10 5 4 5 10 5 7 4 3 8 4 7 4 22 43 16 16 Good Good Good Fair Good Very good . . Very good. . Very good . . Very good . . Very good . . Very good . Good Good Good Good Good Good Good Good Good Good Good Good Good Good Good Good Good Good Very good. Good Good 8 12 6 30 5 24 6 10 12 15 15 6 30 3 18 24 15 18 6 12 3 6 6 10 6 15 10 12 8 4& 84 60 60 42 30 80 48 6 12 60 54 60 36 30 48 48 36 24 24 36 48 60 60 36 Practical Fig Culture; in Arizona 13 The table does not show the missing trees. The varieties that have l5een removed are White Neri, Salmo Sambach, Celestial, Maslin Capri No. 43, and one tree each of Maslin Capri No. 91, Capri Milco, and Capri Elanford. The orchard had been trained to a single standard. There are at this time the Cernica, Mission, Rose Blanche, Magnolia, Capri No. 3, Capri Milco (two trees), Bardajic, Capri No. 2, Salmo Sambach, Capri No. 1, Lob Injir, Black Smyrna, Lemon, Bulletin Smyrna, and Black Adriatic that have not been killed back to the root. The remaining varieties are now producing two to six standards — mostly three to four. Table IV "gives the number of stems for each plant, condition of the plant, together with height and spread of top, and length of new growth. These data give a good i dea of the comparative hardiness of individual trees. Fig. 4. — rView of the third section of 2 trees. Note condition of the trees in row B, and group of weak trees with a third lot of healthy plants. To the left of row A and in the background may be seen a large specimen of Bulletin Smyrna which is also free from winter injury. From photo- graph taken by W. H. Lawrence. Influence of temperature. — The condition of the plants is largely due to the severe weather occurring from December 26, 1912, to January 15, 1913, which was conspicuously abnormal. The follow- ing table shows the character of the weather for that period. 14 EULIvETiN 77 2; o M H U O K Q Is < > M o O CO O '-I ►4 Oi SJ —I > - Q ^ c < < o W ' — ' w & o a K o M o a w u w Q o 1 -w 00 CO ^ ^ CO lO W O ■* 2; as ■* w 05 eo w i-H ^ W CO CO W CO T}< ■* CO CO VI Tt< m Tfi t—i CO (M w 00 CO fTj CO IM tn o CO sj o CO bl TjH CI W •* CI W *"* ^ -* Tf -^ ^ w ^ Tt< tn o CO i-H ^ (M CO W to OA ^ CO C^l W CO CI M CO CI W 00 Cl ^ '"' ■* WJ to ^ "* ^ -* -* tn Ol t^ 05 ^ CO r- w CO f— 1 Z c T-H H to CI W r- T-H ^ CI CO frT TtH w to ^ ■* Tf< ^ Tt< 2; to 00 (M ^ CO "* M 00 CO ^ 00 CO 15 C5 CI W o CI 2 CO 1-^ W "st* IS to ■* rt< ^ % to to 2: r^ o. ^ ^ to (M W IM (M ^ o iM W CO CI ^ lO T-H ^ t^ ■^ ^ CM ^ 2 to to to to to Z to o CO to to ^ ^ c 1—1 w to to (M ^ ^ ^ CO to CI ^ 00 to T-H 0} to CO ^ lo tr- io CO ^ .CO CO (M w 00 •o CO ^ to ^ ^ o CO T-H ^ OT T-H CO CI tfi CO CO CO ^ ■* 00 ^ ^ ^ -* M 1-H (N ^ rH CO ^ CI CI tr. Tf CO ^ to CO ^ ^ »o ^ CO CO III CO CD CD m CO CO 00 Tf ^ to CO w T~i CO ^ o ^ ^ T-H CO W CI CI ^ to '•' lO :? CD CO Z CO en CO w CO III CO r^ ^ ^ ^ t-H w 00 (M ^ o (M W o o w CO CI w CO CO p: lO 2; CO ^ to to CO £« CO w CD m lO •^ ^ CO r^ w o CO w I^ CI ^ t^ CJ w o ^ M CI CO ^ lO CO ^ CO w lO to W o CO c 0 '^t* CO ^ o 00 w t^ to W (N (M K CO CO rrt t^ ^ W f- CI ^ ^ lO w CO 2; to to « to T-H W to Tf to CI ^__, CO rf ^ t- r^ w to r- H CO CO W 00 .-H to to Z to ^ m -* w to to m o 00 CO ^ CO (M ^ o ■* M o ^ (Tj to CI w -^ ^ to Iz >o ■* t- ^ Tf z Oi CO TT ^ CO CO ^ (M (M M CO ^ W CI w o> CD fTl 00 CI w •* ^ w Tf< CO CO ;s CO CO a-. fM w CO (N ^ to T-H ^ >-H (M K ^ CI w ^ CO M ^ ■* w CO CO Z CO ^ CO CO w CO CO m CO lO rn CI CO ^ (M (M ^ o to 1^ CO -* M CO to m to C5 m i CO CO ?5 CO CO CO CO CO rH (M w on "^ w 00 I— ( ^ rt< CO a CO to W CD to w 00 Tf M -* w CO z CO CO CO t/j CO CO CO CO z -^ to w ^ (M ^ rH (N w •CD to w to to w I- CO W -rt< "* ;? CO CO CO CJ ^ CO w 1—* CO z CO '^ w '^ ^ W o ^ % CD CD M d CO w CO "Ch TtT ■* -5j< z; ^ CO CO CO ^ CO r^ oo ^ a> Tt^ w CO to fTl CO (M (ij CO -* W to CO w 00 CI w Tt< CO iz; ^ CO CO CO Oi CO CO CO ^ CO (M ^ CO '^ fTl 00 T-H PjJ t^ to w tv CO rn CI to w ^ ^ ^ -^ CO CO IS CO "* 1—1 (M ^ r- T-H ^ CD to [T^ r^ (N ^ t^ CO M l^ CO M ^ Tt< W '^f w CO 15 ^ CO CO CO ^ % o >. o ■*-' >, r-' o 'A u ■ C >, O -J-» >! o u >. o 4-> >. c o *-> f-" CJ a "a CJ 0/ a a; a ■I-J "o OJ a 'o OJ a o a o E o S O E O O E o E o E o CJ QJ Oj a J OJ OJ D OJ --^ (U n< Q H > Q H > Q H > Q ^ > Q H > Q H > Q 9j (N , CO ■*-> T— I rri r- on Oi o T-H rH C 0 i-H Q OI IM (N !N CO CO 03 T-H Practical Fig Culture m Arizona 15 o c J 3 ;3 .5 h-« a HH o Q U ^ < . w ^ > >< M P u .-T O U hJ z w (-( > - CO T— I C5 lO o P ^ < UJ t— , w « o p H H < CM « 1 — 1 ta Ci &i T— 1 S ^ w CO I- (N > 0^ > t— t tl « PQ p § o W K u w w Q ffi H § o O (^ '^ to M ^ o K- c« m 1- 0 ^ zt: "o K ^o. ^ -^ C-t U3 (M « coco z 00 CO w CO m ^co K CO lO M CO ^ > ^^ ^ g^ 1 ?5^ 1 1 ^"^ w o I— 1 OS -* W l> '^ M O IM > 00 (N > t^ CO tij 0 CO ^ Oi -* M CO CO CO '^ 1 OS 1 00 05 fO W 03 (N W 00 CO fe. rf T-i !> 0 Tt< ^ CO tn 05 CO ^ CO CO Oi IM M CO *^ ■* (N W lO 1— 1 t^ CO (M ^ CO w CO w ^ CO ^ C^, ^ K t^ tp- iM K _o (^:) ^ 1 (M CO ^ -* CO ^ CO M CO CO -* CO > CO ^ '^ ^ CO -* 1 ^ O 1— 1 •> CO ■* > CO ts '* CO. ^ CO OT i> CO > CO ^ cr. ,-H K Tt< CO lO rt* (M > Tf CO ^ CO ^ o »o > CO ^ I> 05 t^ ^ CO 02 CO 0 ^ CO r-f 1/1 05 CO > ^ (M [1! CO ts uo ^ I TtH ic CO > CO l> lO 'SH K 0 r^ ^ O! C5 ^ CO m ^^ 1 JS"^ w CO CO E> t^ CO > CD ;> CO CO > CO ts .-f 00 ^ Ci 00 ^ CO m 1 § ^ ^ g ^ B ■ CO P 5D iM CO t> 00 t^ ^ 0 rf< ^ to w CO to 0 0 M Id .-H ^ 1-* 00 CO M CO ^ C5 ■* ttj 05C5^ coco^^Iooco^ CO izi CO t^ CO ^ C5 0 tJ < i 1 1 o o CO M -.O lO ^ GO t^ > CO (> ;*co> coco^ r-oK CO P^ CO to TJH rH ^ r-4 t^ (M ^ CO lO M M CO w 010^ 'J^fNcoiO'^^ o 00 rH ^ 1 CO Tt( ;jj CO CO ;ij CO m CD CO ^ IM CO 02 CO CO (M t> 2^ ^ t- rH W ^ 15 ^co CO ■^ <—! M CO ^ »0 CO "T- CO '^ 00 10 ^ CD (M M CO (M CO IM O CO ^ CO (M W CO w »0 (M 17 CO CO t- co i^ CO l> 00 rH a l-H CO oc. „ (M (M ►jr lO CO ^ 00 10 M CO *^ ■* CO > CO ts ^^ w C2 (M tij O) CO W ■ CO (> 05 •<* tlj Oi CO W IM -^ cc O (M Kl Ci ^^ M CO 0 CO dj CO t> 1 (M t-H CO CO [4 O (N W 0 t- PU ^=° ^ "O CO ^ (M CO ^ > H y) l-H »"~ u -. o r ) Z > p l-H CO 1—1 •4 •-0 1 — 1 P > rr', O «t1 a p ^ 2; c« < W >— > p:i p (J t-i H < .. 1^ (M 1 — ( T— 1 W CO H (M >< di i-J W » EQ P ?! u W tfl u w w Q w tH S o O 1^ t< M ^ o w t/J w n < 1 «rf Oi '^ tiJ c; c^i W 1 CO lo CO W CO ^ '^ ^ 1 CO (M w CD (M Z 1 CO CD w l-H CD c tt '^ to t- -# H CO z o - ^ 1 ^ 2 1 -* 2 2| M ^ a 1 LO X 1 LO !N ^ -f 2 CO rH ^ o (N sa r- iM M CO ^ C' CO 2 ^ ^ 1 t^ ^ ^ -* Z cci ^^ ^ n; c^ w CO CO ^ 0-1 CO LO 2! t CD ■— 1 5r GC 01 > r- CC !M > O CD ^ CO (M a '^^ 2 -t< CO 2 l> i.':) -f tj C' i lO ^ 1 t^ CO ^ 5 ^ w CO (N ^ 10 to IC r^ CO ^ CO 00 ^ CD CO W ■ ■* Pr} CO to rt* CO W CO t/} '^ ,-1 CO w CD UO IiJ ^^ w CO ^ ni ^ w "0 (M Iz CO "^ 00 l-H fjj 00 l-H w 0 CD M "^ ^ w 'do (M ^ M CO - ^ w CO (M 'z CO '^ 00 ^ W (N to 00 (N H t^ (M M CO ^ ^ -* w t^ IC t^ M CO ^ O (N W (N CO ^ CO 2 r^ (N tt c^ 2 « CD C<) W CO ^ r; '^ w to CO CD W CO M C: CO 5- CO '^ CO to C: CO ►> to 0> (N W CO to (N 10 pcj in CD CO M CO t^ CO W CO to CO ^ 05 I— 1 > to 0 (N W -* to 2 "^ w Ml »0 lO tJ CO " t> 00 fe. CO S^ CO t^ C CO ;> CO ^ O (N CO w to (N (N H r-H -^ M CO CD TjH bj CO ^ (N CO ^ Th 12; i> CO > CO l> l-H I— 1 ^ CO to T-H T— t CO W '^ ^ a (M 10 III ^ym^^ fen relat Fig. (j. — Side, apical. Ion l A Weather Bureau Shelter, with native forms of vegetation adapted to the region — ^cacti, desert grasses and Farkinsonia trees in the background. Relation of Weather to Crops AND Varieties Adapted to Arizona Conditions By Alfred J. McClatchie, J. Eliot Coit and the Station Staff Tucson, Arizona, October 20, 1916 UNIVERSITY OF ARIZONA AGRICULTURAL EXPERIMENT STATION GOVERNING BOARD (Regents of the University) Ex-Officio Hon. George W. P. Hunt, Governor of the State Hon. Charles O. Case, Supt. Pub. Instruction Appointed by the Governor of the State Frank H. Hereford, Chancellor William V. Whitmore, A. M., M. D., Treasurer William J. Bryan, Jr., A. B., Secretary Lewis D. Ricketts, Ph. D., Regent William Scarlett, A. B., B. D., Regent Roderick D. Kennedy, M. D., Regent Rudolph Rasmessen, Regent Frank J. Duffy, Regent RuFUS B. von KleinSmid, A. M., Sc. D., . President of the University AGRICULTURAL STAFF Robert H. Forbes, M. S., Ph. D., Director John J. Thornber, A. M., Botanist Albert E. Vinson, Ph. D., Biochemist Clifford N. Catlin, A. M., Assistant Chemist George E. P. Smith, C. E., Irrigation Engineer Arthur L. Enger, B. S., Assistant Engineer George F. Freeman, B. S., Plant Breedei Walker E. Bryan, M. S., Assistant Plant Breeder Stephen B. Johnson, B. S., . . . . . Assistant Horticulturist Richard H. Williams, Ph. D., ..... Animal Husbandman Walter S. Cunningham, B. S., . . Assistant Animal Husbandman John F. Nicholson, M. S., Agronomist Herman C. Heard, B. S. Agr Assistant Agronomist Austin W. Morrill, Ph. D., .... Consulting Entomologist EsTES P. Taylor, B. S. Agr., Director Extension Service George W. Barnes, B. S. Agr., Livestock Specialist, Extension Service L. S. Parke, B. S., Boys and Girls State Club Agent Edith C. Salisbury, B. D. S. . . . Home Economics Specialist Arthur L. Paschall, B. S. Agr., . . Countj^ Agent, Cochise County Charles R. FillERUp, D. B., . County Agent, Navajo-Apache Counties Alando B. BallanTyne, B. S., County Agent, Graham-Greenlee Counties John R. TowlES, Secretary, Extension Service Frances M. Wells, Secretary, Agricultural Experiment Station The Experiment Station offices and laboratories are located in the Univers'ty buildings at Tucson. The new Experiment Station Farm is situated two miles west of Mesa, Aiizona. The date palm orchards are three miles., south of Tetnpe ((cooperative, U. S. D. A.), and one mile southwest of Yuma, Arizona, respectively. The experimental dry-farms are near Cochise and Pres- cott, Arizona. Visitors are cordially invited, and correspondence receives careful attention The Bulletins, Timely Hints, and Reports of this Station will be sent free to all who apply. Kindly notify us of errors or changes in address, and send in the names of your neighbors, especially recent arrivals, who may find our publications useful. Address, THE EXPERIMENT STATION, Tucson, Arizona. CONTENTS Page Introduction 45 Effects of weather on different crops 46 Method of keeping weather records 46 Factors influencing results 47 General effects of temperature 47 General effects of direct sunshine 48 General effects of aridity and of rainfall 50 Varieties 51 A look into the future 51 The crops of Arizona 52 Alfalfa 52 Amount to sow 53 Varieties 54 Cutting and curing 55 Almonds 56 Apples 57 Apricots 57 Asparagus 58 Bananas 58 Barley 58 Beans, field ■ 59 Beans, snap 61 Beets 61 Sugar beets 62 Berseem 64 Blackberries 64 Broomcorn 65 Buckwheat 65 Cabbage 65 Canaigre 66 Carrots 67 Castor beans 67 Cauliflower 67 Celery 68 Cherries 68 Clover 69 Corn 69 Cotton 69 Cowpeas 70 Cucumbers 71 Currants 71 Dates 71 Eucalypts 72 Feterita 74 Figs 74 Gooseberries 75 Grains 75 Grain sorghums, — Kafir, milo, feterita, shallu, and kowliang 77 Grapes 79 Grasses, — Bermuda, blue, brome, Johnson, orchard, and rye 80 Page Guavas 82 Kafir and Egyptian corn 82 Kowliang 82 Lemons 82 Lettuce 83 Loquats 83 Millet 84 Milo maize 84 Mulberries 84 Muskmelons 85 Oats 85 Olives 85 Onions 86 Oranges 87 Peaches 87 Peanuts 88 Pears 88 Peas 89 Pecans 89 Persimmons , 90 Plums. 90 Pornegranates 91 Pomelos 91 Potatoes 92 Pumpkins and squash 94 Quinces 94 Radishes 95 Raspberries 95 Rhubarb 95 Shade and ornamental trees for planting in Arizona 96 Shallu 97 Sorghum 97 ' Spinach 98 Squashes 98 Strawberries 99 Sudan grass 102 Sweet clover 102 Sweet potatoes 103 Tobacco 103 Tomatoes 103 Tomato insects and diseases 106 Turnips 106 Velvet beans 106 Walnuts 107 Watermelons 107 Wheat 109 Recapitulation 109 What may be planted and what matures each month 110 When each crop may be planted and when it matures 112 i; ^ RELATION OF WEATHER TO CROPS AND VARIETIES ADAPTED TO ARIZONA CONDITIONS Being a Revision of Bulletin No. 61, by Alfred J. McClatchie and J . Eliot Coit. By the Staff of the Arizona Agricultural Experiment Station. INTRODUCTION In the following pages the aim is not only to record and discuss observations made during the past 18 years upon the relation of Arizona weather to crops, but to indicate as far as possible those varieties which by popular experience and Station tests have proved best adapted to the region. The large number of inquiries concern- ing crops adapted to different sections of the State indicates the need of keeping our printed information on this subject up to date. As new settlers are constantly coming into the country, and as the indications are that large numbers will continue to come in the future, a publication giving such general information will undoubt- edly be useful. This publication is a thorough revision of Bulletin 61, by J. Eliot Coit, which, in turn, was a revision of Part III of Bulletin 4», by Alfred J. McClatchie. The arrangement and much of the body of the publication are essentially the same, but considerable new matter has been added, and information concerning the various crops and their adaptability to different parts of the State has been revised in accordance wnth new developments and the added experi- ence of the past several years. This information has been secured from records which have been accumulating at the Experiment Station farms, and from personal visits and correspondence of the different members of the Station Staff throughout the State. The total agricultural products that Arizona will yield is limited principally by the quantity of water available. The area of arable land is far in excess of the acreage for which water can be supplied for irrigation. A large amount of this non-irrigable agricultural land lies in districts having enough rainfall to make dry farming prac- ticable. In the most favored of these regions the rainfall is insuf. 46 BuLi^ETiN 78 ficient to utilize to its fullest value the natural soil fertility. In these regions, therefore, those methods of farming must be adopted and those crops selected which best conserve and most efifectually use the limited water supply. The nature of these crops is deter- mined largely by the climate of the region. EFFECTS OF WEATHER ON DIFFERENT CROPS METHOD OF KEEPING WEATHER RECORDS For several years a record was kept at the Station Farm of the temperatures registered by maximum and minimum ther- mometers situated at various elevations from the ground. Besides the thermometers furnished by the Weather Bureau and kept in a regular instrument shelter, three sets of instruments of the same grade have been located on the south side of a post in the full sun- shine, and daily records made from them. One set was located within a few inches of the soil, the second five feet above the ground, and the third was situated 10 feet above. For a year and a half three self-registering thermometers have been located underground upon a movable frame standing in a small shaft, one instrument being located five feet below the surface, one 10 feet below, and one 15 feet below. Records have been made from these instruments once a week. Besides the above regular and continuous records, thermometers have been exposed among various growing crops, both above and under the ground, and records made therefrom. By these various methods an attempt has been made to ascertain and accurately register the actual temperatures to which crops have been exposed, both at various distances above the surface and at various depths underground. The records kept from the instruments located in the government shelter and from the set located on the post at 5 feet from the ground furnish a comparison between the temperatures "in the shade" and those in the full sunlight. And as the instruments at the Phoenix Weather Bureau office only two miles distant are located 50 feet above the ground, the record reported from them furnishes data for quite a fair comparison between temperatures at that elevation and those under similar conditions 5 feet from the ground. The work has also included keeping an evaporation record and carefully noting the effects of the weather on the various crops of the farm. Relation of Weather to Crops 47 factors influencing results In considering the effects of the weather on different crops some difficulty is experienced in distinguishing with certainty between the results caused by the different phases of the weather and those caused by soil conditions. Differences in the physical and chemical conditions of the soil, especially differences in the amount of alkali, cause more or less marked differences in the success with which crops resist unfavorable weather conditions. These facts have been given due consideration and an attempt has been made to discriminate as accurately as practicable between those results due to differing soil conditions and those due to the effect of the weather. In the study that has been made of the effects of the weather upon crops, five factors have been considered — temperature, direct sunshine, relative humidity, rainfall, and wind. Of these five the first has the greatest influence and the last the least influence. High temperatures limit crop production in southern Arizona con- siderably more than low temperatures. Relative humidity has a greater influence on crops than the local rainfall, the latter being too scanty most years to affect results very much. Most of the wind that occurs in the region affects vegetation principally by influencing the rate of evaporation of water from it, the velocity seldom being great enough to directly damage crops. General Effects of Temperature High and low temperatures affect crops in various ways, the principal ones being by preventing germination, by checking growth, by kilHng part or all of the vegetative parts, by injuring the blossoms, and by damaging the maturing product. The most pronounced effects are brought about in the first two ways and the least injury through the last. Crops affect considerably the tem- peratures about and among them. Through the cooling effects of evaporation and radiation combined, the temperature becomes lower among growing plants during cool nights than it is over bare ground, the difference varying from four to eight degrees. During the day also the rapid evaporation of moisture from vegetation causes the temperature to be a few degrees lower among plants than elsewhere. The temperatures to which crops are subjected are, therefore, more trying during frosty nights and less trying during 48 Bulletin 78 hot days than thermometers situated outside of their foilage would indicate. The seed of most crops will germinate only during one or more definite portions of the year while the temperature remains within certain limits. For the seed of some crops this period is during the cool part of the year and for the seed of others it is during the warmer part of the year. Seeds of the former class either decay or remain dormant through the portion of the year during which the temperature is too high for germination and seeds of the latter behave similarly during the cooler portion of the year. The seed of a very few crops germinates here promptly during all parts of the year if supplied with water and of a few others the seed germinates during all of the year, except the hottest weather of summer and the coldest weather of winter. Most crops make growth only during the portion of the year that the temperature remains within certain limits, maturing, dying, or becoming dormant when the temperature falls too low or rises too high. Most annuals grow continuously during a certain portion of the year and either die or mature w^hen the weather becomes too cold or too warm, as the case may be. A few become dormant as unfavorable weather comes, resuming and finishing growth when the weather again becomes favorable. Most deciduous perennials grow during one portion of the year only, while most evergreen perennials make fresh growth during two distinct periods of the year, remaining dcrm^ant or being killed back during other portions of the year. General Efccts of Direct Sunshine Direct sunshine has an effect upon plants different from the effect of diffuse sunlight at the same temperature. Any solid sub- stance that intercepts the sun's rays becomes heated thereby to a greater or less degree. A shaded object does not become as warm as one exposed to the direct rays of the sun in an atmosphere of the same temperature. This is due to the absorption of radiant heat from the sun by the exposed object, as previously explained, while the shaded object becomes heated only by contact with the warmer atmosphere. In the shade, therefore, not only is the temperature of the air lower, but absorption of heat from the direct rays of the sun does not occur. Hence, the difference between the temperatures of the soil and of objects in direct sunshine, and of the soil and of ob- jects in shade is considerably greater than the difference between the Relation of Weather to Crops 49 temperature of the atmosphere over or about the exposed objects, and that over or about the shaded objects. Shutting off or admit- ting sunlight, therefore, has a double effect upon plants. During weather too cool for the normal growth of a plant, direct sunshine promotes its activities and results in benefit, while shade has the opposite effect. The almost continuous bright sunshine of our winters is, therefore, a distinct advantage to vegetation and results in more rapid growth than could take place in a cloudy region where other conditions (both of soil and of weather) are the same. It has the effect, however, of unduly warming during the day decidu- ous trees in their leafless condition and causing some of them to bloom so early some years as to receive injury from frost. During the warm portion of the year, parts of many plants become overheated in direct sunshine and injury to tissue results. This is especially true of the trunks of fruit trees which are exposed to the sun on the southwest side. Sometimes fruits, such as oranges, for example, will become sunburned and stunted in growth by exposure to the direct rays of the sun. Occasional injury to the leave's may occur, but injury to the stem is far more serious. More- over, since the leaves are continually being cooled more or less by the evaporatiion of moisture from their tissues, they do not become as highly heated as do stems and tree trunks from which very little evaporation is taking place. Hence, plants with heavy foliage that shades the other parts have a distinct advantage, other things being equal, over ones with slight foliage, provided they are supplied with sufficient water. Not only does insufficient or improperly located foliage result in the overheating of exposed stems and other pjarts, but the soil immediately about the plants becomes so highly heated as not only to seriously injure shallow roots but to radiate heat so rapidly that the effect of the direct rays of the sun is thereby much augmented. For two reasons, therefore, it is important that varieties of fruits, vegetables, and other crops be selected having a heavy foliage not sensitive to heat and that trees and shrubs be headed low. Pro- tection to st^ms or trunks, to roots, and to the maturing crop of fruit or vegetables is thus secured. Similar results are also obtained by close planting of vegetables, one plant thus shading its neighbor and all shading the soil. The crops for which such precautions are important are such as peas, beans, tomatoes, squashes, melons, and strawlerries. 50 Bulletin 78 General Effects of Aridity and Rainfall Of all the crops discussed in this bulletin, not over half a dozen grow better (other conditions being equally favorable) in a climate having a very low relative humidity. All the others thrive best in an atmosphere having a somewhat higher relative humidity than prevails in southern Arizona, providing all other conditions are favorable, and the growth of many is seriously retarded by the aridity of the region. Several crops, though the temperature be favorable, and though supplied with plenty of water, do not grow well during those portions of the year when the relative humidity is very low. Very rarely indeed is the atmosphere of the region too damp for the proper development of any crop. As a water supply the direct effect of the local rainfall is not great, comparatively little benefit or injury to crops resulting from the small amount of water that falls. Indirectly, however, the local rains benefit many crops. The higher relative humidity that accompanies them is a benefit to most crops at any time of the year, and the lower tem.peratures that accompany the summer showers are a relief to most crops during that Reason. Local rains are ordinarily heartily welcomed, however, chiefly because as a rule rain falls at the same time in the region furnishing the supply of water for irrigation. Only occasionally is the local rainfall heavy enough to directly benefit the crops, and then only shallow-rooted ones are much benefited, since the soil is rarely wet to as great a depth as one foot during any one storm. When it is considered that the total annual rainfall of the region is only five to eight inches, much of which falls in such small amounts as to fail to reach the roots of plants, and that amounts ranging from 20 to 50 inches in depth are needed for the proper development of various crops, it will be evident that the effect of the local rainfall as a water supply is not great. The combined effects of the factors discussed above — temper- ature, direct sunshine, relative humidity, and rainfall — together with that of the wind, are taken into consideration in discussing the crops whose relation to the weather is given in the pages that follow. Upon some crops the effect of one of these factors is greatest, upon others the effect of another is greatest. Relation of Weather to Crops 51 VARIETIES A Look into the Future Varieties of crops originate in two chief ways. A new variety- is either the result of intentional breeding and improvement by selection which had been carried on for a number of years, or it comes into existence by chance — fortuitous variation, as the scientists would say. In any event it is obvious that the characters on whose account the variety is considered valuable to man are (in nearly every case) first noticed at the place where the variety originates. The new form is therefore preserved and propagated because it has developed and displays some new and valuable characteristics under the climatic and soil conditions existing at the place of its origin. The same variety, however, reacts very differently to the various stimuli produced by different environments. Hence we arrive at the commonly held and correct idea that each climatological area has its own peculiar set of varieties which succeed best under its own climatic and soil conditions. While these areas are only vaguely defined and overlap in many cases, we know of very many specific instances where differences in adaptation are unmistakable. As most of the climatic divisions of the continent have at least some factors in common, the interchange and adoption of varieties from one to the other have gone on simultaneously with the develop- ment of local varieties. This procgiss is of course taking place in the arid Southwest, of which Arizona and Sonora are a part, but with less satisfactory results, perhaps, than anywhere else. Of the seventy-two crops discussed in the succeeding pages, only about thirty-five have a variety which succeeds as well in the arid vSouth- west as elsewhere. Two reasons may be given to account for this state of affairs. In the first place, the qjimate has little in common with any other region, for here we find that lowest rainfall, lowest relative humidity, and greatest percentage of sunshine occur together; and this is true to the same extent of no other area of North America. In the second place the agricultural activities are so compaiatively new that local varieties have not had time to develop. These remarks lead us to the conclusion that the arid Southwest, of all the areas on the continent, is most in need of and will be most benefited by local varieties of crops which flike the Arizona Ever- bearing Strawberry) have been produced in the region'. Whether thev are intentionally produced or accidentally discovered, they 52 Bulletin 78 will be preserved and propagated for the sake of original values displayed under Arizona conditions and not because they may have a high color when grown in California or a fine flavor when grown in Michigan. THE CROPS OF ARIZONA (Arranged Alphabetically) ALFALFA As a commercial crop alfalfa has been grown in Arizona about forty-five years. It succeeds admirably in all parts of the State where suitable soil and sufficient water are available. It is little affected by altitudes encountered within the farming sections of the State. It succeeds in the Imperial Valley of California, below the sea level and on the farming lands around Prescott and Flagstaff at elevations of over 6,000 feet. When supplied with plenty of water it will make some growth in every month of the year in the lower valleys, but at the high elevations of northern and south- eastern Arizona it is completely dormant in winter. Seven cuttings are the rule in the vicinity of Yuma, six cuttings in the Salt Rivef Valley, five in the upper Gila Valley, and from three to four at high altitudes in the northern part of the State. Growth is most rapid in spring and early summer, and the second cutting is usually the heaviest. In midsummer, due to the intense heat and the attacks of leaf hoppers and the larvae of the alfalfa butterfly, the crop is usually light, but with the coming of the cooler weather of September, the growth is more vigorous. Varieties differ in this respect. The ordinary American and Turkestan types show most the fcflect of summer retardation of growth, whereas the Peruvian and Mediterranean alfalfas show least. Alfalfa can be sown with a good chance of success during any month from September to May. If planted during the warmer months, the ground loses moisture so fast that it will dry out deeper than one dares to plant the seed before it ha? time to germinate. When the seed is again irrigated before coming up, the ground bakes around the seedlings so tightly that they are unable to force their way to the surface. Stands may be secured in the hottest weather, but in order to do so the seed must be planted shallow and then watered every two or three days until the plants are up. Such a proceeding would be impracticable in large Relation of Weather to Crops 53 fields; alfalfa is, therefore, best planted during the cooler weather of fall, winter, or spring, when evaporation is not so great. The conditions are then usually such that the seed may be planted in a moist and well prepared seed bed that will retain its moisture long enough to bring up the plants without further irrigation. When, however, a second irrigation is necessary, the ground does not bake so quickly and the seedlings will, for the most part, get through the surface before a crust is formed. Good stands of alfalfa that were seeded in winter (late November to February 1) are common, but seeding during t^is season is risky on account of frost injury. If a hard freeze occurs soon after the alfalfa gets through the surface, when it has yet but two leaves, and especially when the soil is damp from recent irrigation or winter rains, a large proportion of the young plants may be killed. The writer knows of an instance where a beautiful stand of forty acres was destroyed in this way. After the young plants have three or more leaves, no degree of cold occurring in Arizona is likely to injure them. Good stands can be secured during February and March. Spring planting, however, is open to the disadvantage that the young plants go into the hottest and driest parts of the summer (May and June) with poorly developed root systems. Th- tap- roots have not yet penetrated deeply and if a shortage of water should occur, which is more liable at this season than any other, the plants suffer from drought and the stand is apt to be seriously depleted. Moreover, spring-planted alfalfa gives but slight yields the first season and requires more frequent irrigation and greater attention than that which is planted earlier. The best time to plant alfalfa is from September to November, inclusive, according to season and locality. Planted at this time, the young seedlings, favored by the mild temperatures of our autumn cHmate, get sufficient start not to be injured by the sharp frosts of December and January. The labor and expense of frequent irrigations are made unnecessary by low evaporation during the cool weather, and this is further reduced by the moisture obtained from whatever winter rains that may occur. While the tops grow but little during the cold season, the root systems are developing steadily. The alfalfa, therefore, goes into the hot, dry period of early summer with wide-spreading and deeply penetrating roots. This enables it to withstand heat and drought and return profitable yields even during the first year of its occupation of the soil. Amount to sow. — Plump, well matured alfalfa seed should number about 200,000 to the pound. Where 15 pounds are sown to the 54 BuLivETiN 78 acre we would obtain 3,000,000 plants if all germinated. Estimating that under field conditions only two-thirds of the seeds produce plants, we would have 2,000,000 seedlings, or about 45 plants to the square foot. This number would be considered a good stand. As the plants grow older they crowd each other and some die. With an original stand of 45 plants to the square foot, more than half usually succumb during the first year. At two years 11 plants to the square foot is an abundant stand, and this will be normally reduced to an average stand of 5 to 6 plants by the end of 4 or 5 years. In dr}' farming, the stand must necessarily be thinner on the ground (2 or 3 plants to the square foot) in order that each plant may secure an ample supply of water. For this reason many growers of alfalfa in f-^miarid sections find it best to sow not more than 8 to 10 pounds of seed to the acre. On the other hand, in humid sections where the danger of weeds is great, 20 pounds to the acre is not too much. When it is intended that the field be devoted largely to the production of seed, not more than 10 to 12 pounds should be sown. Varieties . — The natural adaptability of alfalfa and the wide range of soil and climatic conditions within which it has been grown, have resulted in many distinct types and races. Whenever alfalfa is grown for a long series of years in a given region from seed pro- duced locally, it slowly becomes acclimatized. Those mixtures or variations which are best suited to the conditions prevailing flourish and crowd out the less favored individuals. Strains acclimatized to a given regioti are called regional varieties. In transferring seed from one country to another the measure of its success is usually proportional to the degree of similarity between the climatic factors of its old and new homes. However, unless we have definite infor- mation as to the exact origin of an imported strain, the length of time that it had been planted in that given region, and the local conditions under which it was grown, we must be very uncertain as to the likelihood of its value in Arizona. Not all strains of alfalfa from Turkestan, for example, have an equal value or climatic adaptation. Local conditions and the number of years they had been grown in that region will largely govern their quality. As an example of an imported strain which has proven valuable, Peruvian alfalfa may be mentioned. The seed of this strain is now being produced in large quantities by the Yuma alfalfa seed growers. It is an upright, vigorous and very productive sort with narrow leaves and light purple flowers. Peruvian alfalfa is inclined Relation of Weather to Crops 55 to be a little stemmy, and the plants are somewhat hairy, but these difficulties are largely overcome when it is grown in a thick stand. Aside from the Peruvian, out of the 26 imported strains tested at this Station only four seem worthy of further trial. These include two from Europe and one each from South America and Turk- estan. The strains from Arabia and the Mediterranean region were very promising for the first year or two of their growth in the experimental plots at Phoenix, but they soon lost stand to such an extent that their yields dropped below the margin of profit. The same difficulty has been experienced in other parts of Arizona where these strains have been tested. The Mediterranean alfalfas are vigorous, among the first to start in the spring, and the last in autumn to cease growth. For these reasons they will generally yield one more cutting to the season than any other variety, with the exception of the Peruvian. Were it not, therefore, for their tendency to lose stand, or if hardy strains of them could be devel- oped, they would make a valuable introduction. Finally, with regard to varieties, it may be stated that with the exception of the Peruvian alfalfa already mentioned, and in the absence of selected, tested, and purified strains of other sorts, our home-grown seed is probably better than any regional strain which we would be able to import indiscriminitely at the present time. The fact that Arizona now is, and should .iitinue to be, an exporter of high-grade alfalfa seed rather than an importer, perhaps more than anything else emphasizes the necessity of carefully guarding the purity of our local type and standard of excellence. Cutting and curing. — The mowers should begin early in the morning, as soon as the dew is off, if such has fallen. As soon as the leaves are well withered, but before they become crisp, the hay should be raked into windrows. If the leaves are allowed to dry into a crisp before raking, many of them will shatter off and be lost in this operation and, moreover, the subsequent curing of the hay in the windrow or cock is not so satisfactory. The reason ascribed for this is that the evaporation from the withered leaves serves to extract water from the stems. If allowed to dry quickly into a crisp their condition is such that they are no longer able to do this. The stems therefore cure slowly and the haymaker must either allow the leaves to become so dry that they are for the most part lost by shattering, or else the stems must be put into the bale or stack with such high moisture content that injury by heating or moulding will occur. 56 Bulletin 78 From the windrow, alfalfa should be ready for stacking in two days and for baling in three days. The length of time required for curing will, of course, depend upon the temperature, the intensity of sunshine, and the amount of wind. A good rule is that hay is ready for stacking when water can no longer be twisted out of a wisp of stems held between the hands. It is not ready for baling, however, until such twisting will cause the stems to break. Many farmers prefer to cure alfalfa in the cock rather than in the windrow. This method is more suited to the intensive farmer and to situations or times when there is danger of showers during the haying season. Hay in the cock resists the effect of rain better than in the windrow and is, moreover, in position to be protected by canvas or paper caps. Where the price of hay is high and the curing must be made in a rainy season, hay caps are frequently used with much profit. Caps made of canvas are prefer- able since they are more durable and are not blown off so badly by strong winds. Such caps, 40 inches square, weighted at the corners, can be manufactured especially for this purpose and sold at about 12 cents each. The hay is usually allowed to remain in the windrow for one day, or until it is about half dry. It is then bunched with the rake or by hand, and thrown into cocks with the fork. Hay cocks are preferably as tall and narrow as possible to allow better cir- culation of air around and through them. Here the hay may remain three, four, or more days until it is thoroughly cured, where- upon it may be baled or stacked directly from the cock. ALMONDS Almonds have been grown with fair success and profit, especially when planted in large orchards where artificial protection of the bloom from spring frosts by smudging is practicable. Some varieties bloom during early February while others bloom several weeks later. The sharp frosts of midwinter and the warm, dry weather of spring and early summer, seem to supply just the climatic conditions needed by this nut. Of late years the prevalence of the disease known as crown gall (see Ariz. Sta. Timely Hint for Farmers No. 118) has caused the profit from almond culture to be very uncertain. Red spiders sometimes cause injury to the leaves, and birds often appropriate the nuts from isolated trees. The I. X. L. is, perhaps, the surest bearing variety, while the Nonpareil grows well and is Relation of Weather to Crops 73 injured, one to four inches of the tips being killed. December 14, 1901, slight injury vras done to the tips of E. rudis and E. leucoxylon, while } ear-old plants of E. rosiraia were nearly all frozen to the ground, the minimum therm.ometers registering 15° F. at the t> o round, 10° V. in tl:c gc\ernmcnt shelter, and 24^^ F. at the Weather Bureau. All arc more or less checked in their growth by the heat of midsuir.mcr, E. pulyaiilluijia being allected perhaps the least of any cf the species mentioned. Some species grow best in a moist atmosphere, but most of them prefer a dry atmosphere. With mod- erate irrigation, the Eucalypts noted above will endure well our hot, dry atmosphere. Eucalypts may be grown from seed in a frame lattice house, the sides of which should be more or less protected with vines. The seeds should be sow^n by the middle of April or early in May in flats containing about 3 inches of clean fine sand. They should be scattered on the surface and covered with a thin layer of sand. The water used in irrigating should be free from alkali and the fla\;s should be covered with one or two thicknesses of newspaper un.il the seedlings are mostly up. They must not be kept too wet, other- wise they will be attacked by a damping-off fungus. \Vhen th^ small plants have 4 or G leaves they may be transplanted in flats containing 5 or (3 inches of fine, sandy, loamy soil; and they should l;e watered regularly. About 100 plants m^ay be set in a flat 12 1// 20 inches in size. From July 1 to August 15 the flats of seedlings should be cov^ered with fine wire screen or mosquito netting to keep June and Goldsmith beetles from depositing their eggs in the moist soil. The larvae of these insects eat the rootlets cf young Eucalypts and may do a great amount of damage in a short time. The Eucal)'^pts may remain in the lattice house during the winter season and be set out the following spring. Eucalypts, like citrus trees, have two periods of thrifty growth, one from March to June, and the other from the latter part of August to the latter part of November. A little growth is made here by a few species during the hottest weather of summer, and a few make some growth during the coldest weather of winter. The most rapid growing Eucalypt (E. globulus) does not endure well our extremes of climate, but the growth of E. nidis, E. tereti- cornis, and E. rostrata is fairly rapid. Judging by their growth upon the Farm and elsewhere, they can be counted on to attain a height of 30 feet and a diameter of 6 inches in four or five years, and a height of 50 feet and a diameter of 1 foot in six or eight years. A five-vear-old E. riidis at the Farm measured 1 foot in diam- 74 • Bulletin 78 eter and 40 feet high; an E. iereticornis of the same age was 30 feet . high and 8 inches in diameter; and E. rostrata trees of this age were 35 feet high and 10 inches in diameter. In Phoenix, at the corner of Adams Street and Ninth Avenue, is an £. ro^/ra/a 16 years old, which is about 90 feet high and over 3 feet in diameter 5 feet from the ground. Eucalypt trees have been thorough!}^ tested at the Experiment Station Farm at Phoenix and have been planted to a considerable extent in the Salt River and Colorado River valleys. They are better adapted to conditions in the Colorado River Valley than to those of the Salt River Valley. Of the 50 or 60 species tested at the Station Farm only 4 or 5 have proven well adapted to our climatic conditions. Of these. Eucalyptus rudis, E. tereticornis, and E. rostrata are among the valuable ones of the genus. Euca- lyptus rudis was planted sparingly in the Upper Gila Valley and succeeded well during a few moderately favorable seasons. With rather cold weather the foliage was killed, and during a recent cold winter all the trees were killed to the ground. In the Santa Cruz Valley about Tucson, Eucalyptus rudis, E. rostrata, and E. polyanthema have made splendid growths and for a number of years were very promising for ornamental and economic purposes. Occasionally they were injured with the coldest weather, but this "was not regarded as serious. During the winter of 1912-1913 the Eucalypt trees about Tucson were killed back seriously by the severe freezes, the lowest temperatures being 6° F. above zero. Since then they have not been planted extensively. Eucalypt culture will probably never prove a success as a saw log industry in any part of Arizona. By planting the hardy spe- cies noted above, however, timber can be grown for fuel, fence posts, and, perhaps, for telegraph poles, railroad ties, and other purposes for which durable hardwood timber is used. In Arizona we must expect occasional severe winters which will materially damage Eucalyptus trees and result in the wood being harvested even in an immature condition, since fresh growth will begin from the base. FETERiTA {See under Grain Sorghums) FIGS Figs are a satisfactory home orchard fruit in all our south- ern valleys except where the altitude is over 3500 feet. Above i Relation of Weather to crops 75 2000 feet elevation it is desirable to protect the young trees by- banking them with soil until they become established. It is doubt- ful if the fig will ever become a commercial crop in Arizona, unless, perhaps, in the Yuma Valley, where the first crop of a variety of black fig, probably the Mission, makes a semi-candied fig on the tree. This fig commands a high price on the market. The Mission is the most valuable variety here because of its hardiness; because it does not need to be fertilized by the Blasto- phaga wasp, and because the first crop is important as well as the second. The Brown Turke}^ and White Adriatic are good varieties which do not require the Blastophaga wasp to fertilize them. Bulletin Smyrna and Lob Injir are Smyrna varieties which, with the Blasto- phaga wasp to pollinate them, have produced abundant crops at Phoenix. With this class of figs it is necessary to raise the Capri fig trees, in the fruit of which the Blastophaga wasp develops. This is the only insect that can pollinate figs and the Capri is the only plant upon which the insect can develop. Figs require a liberal supply of water and great care in trans- planting. Methods used to transplant most trees will kill fig trees. The slightest drying of the roots kills the tree. Figs grow readily from cuttings made from one-year-old wood. 9 to 12 inches long, planted to within one bud from the top. Cut- tings need frequent irrigation. gooseberries These humid climate loving plants succeed well in the moun- tains at high elevations. In the hot and dry southern valleys, however, their growth is attended with considerable difficulty and they have never been cultivated extensively with profit. The Houghton has been grown in an experimental way near Phoenix, but the prospects for a money profit in gooseberries are not encouraging. GRAINS Barley, wheat, and oats are not killed or seriously injured by the lowest temperatures that occur in southern Arizona. On the contrary, they continue to grow during most of the coolest weather of the year. Occasionally some injury is done to the bloom of grains during spring, but the loss from this cause is not great. It is the hot dry weather of summer that the small grains and most 76 Bulletin 78 of the perennial grasses can not endure, their growth being Hmited almost entirely by heat rather than by cold. The season during which seed of the above grains germinates begins during September, after the mercury ceases to rise above 110° F. in the shade during the day, and begins falling as low as 50^ to 60° at night, and continues until the next May when tempera- tures higher than the above occur. During the hot weather of June, July, and August the seed v.nll not start, even though supplied with plenty of water. Barley and early varieties of wheat sown and irrigated during September sometimes head out during December, especially if the autumn be warmer than usual; but ordinarily all grains head out by the end of April, regardless of the time of seeding. Fall-sown winter varieties of wheat do not usually begin stooling until after the coolest weather of winter is over, but most other grains begin stooling earlier, if sown during early fall. Grain sown during the latter part of Januar}^ and duri'ng February makes an uninter- rupted growth from the time of germination, and matures before the weather becomes extremely hot. Grain soAvn later then Feb- ruary does not have sufficient time for full growth before the hot weather of May and June. November is ordinarily the most fa\orable month for sowing grain. Evaporation being compara- tively slow during the weather that follows, grain sov;n in moist soil during this month usually needs no irrigation until February or March if there is an average amount of winter rainfall. All sowings of all varieties ordinarily ripen during May or the few days that precede or follow this month. At this time of year the w eather is usually very favorable for harvesting cf the crop. The principal grains sown are barley and wheat, though oats and rye are also successfully grown, but to a much smaller extent. The yield of grain is from 1500 to 3GC0 pounds per acre, depending upon the soil and M^ater supply. The white varieties such as Sonora, Early Eaart and White Australian are chiefly grown, although durum wheats produce well. Macaroni is probably the heaviest yielder, but is not used by the millers. Where grain is grown for poultry or stock feed, macaroni wheat is to be pre- ferred. Among the bread W'heats, Earty Eaart, a variety intro- duced by the Experiment Station about the year 1900, is now preferred by the millers on account of its high quality. It is now the most widely grown variety in the vState. Marquis and Turkey Red will do well at the higher altitudes. Relation of Weather to Crops 77 All varieties of barley do well. The variety of oats most widely grown is Texas Red. For winter pasturage and an early crop of hay, barley, wheat, and oats are grown instead of the grasses used in cooler regions. These grains are sown both upon the fields of alfalfa and in freshly plowed soil. In the former case the seed is covered with a disk harrow. In fresh soil the seed is either disked or harrowed in. When sown upon alfalfa fields, seeding is usually done during early fall. In fresh soil seeding is done throughout fall and early winter. The resulting growth is commonly pastured during winter, and then permitted to grow up for hay during spring, being cut in April and May, when the kernels are quite well formed. Oats make the best hay, and they are now sown for this purpose more gen- erally than formerly. The usual yield of grain hay is one and a half to three tons per acre. GRAIN SORGHUMS The sorghums are divided into two classes^ — the saccharine, used for syrup making or for forage, knd the non-saccharine or grain sorghums, used for grain and forage. The grain sorghums are of tropical origin, and flourish best in hot climates. They are very drought resistant, and well adapted to the semi-arid Southwest. They develop well with eight to ten inches of rainfall during the growing season. Grain sorghums are divided into three classes, according to the character of head: 1. Kafir, with compact, erect heads. 2. Durra, with compact, pendant heads. 3. Broom corn type, with loose spreading heads. The varieties of grain sorghums profitably grown in Arizona that belong to these classes are as follows: Black-hull white Kafirs, dwarf and standard. White milo or durra. \ ellow milo, usually called Milo Maize, dwarf and standard. Feterita, one of the Durras. • Shallu, a broom corn type, sometimes called Egyptian wheat. Kowliang, another broom corn type. Kafir The Kafirs, of which there are three varieties, the White, the Red, and the black hulled White, are very drought resistant. They 78 Bulletin 78 were introduced from South Africa and will endure for extended periods awaiting rainfall, without apparent injury to the plant. As soon as moisture is supplied Kafir will renew its growth and continue to mature its grain. The growing season for Kafir is about 120 days, or longer when growth is arrested by insufficient moisture. The date of planting in both irrigated and dry-farming sections should be as early as late spring frosts will permit. Under dry- farming conditions in the southern part of the State it is well to put the crop in as early as March 10 to 15 in order to take advantage of winter moisture. Black-hul) White Kafir is the most popular variety grown in Arizona both for grain and silage purposes. Milo Maize The term Durra is so little used that this group is considered as Milo Maize. The Durras include white, brown and yellow milos and are characterized by large flat seeds. Feterita, a more recent introduction, also belongs to the Durra group. This group of grain sorghums was introduced from North Africa. Like Kafir, Milo Maize flourishes in the hot dry climate of Arizona. The time required to produce a crop of yellow milo is about 100 days or nearly three weeks shorter then Kafir. The Milos are better grain producers than the Kafirs, but are not as good forage crops. Dwarf types of milo have been developed superior to the tall cr standard types for production of grain. Under dry-farming condi- tions the Milos should be planted in July in southern Arizona. The summer rains begin at this time and the season is long enough after that date to mature a crop. In the northern part of the State, w^here these crops are grown by dry-farming, planting should be made about May 1. In the irrigated sections the Milos should be planted in April. Two crops of milo can be harvested from the April planting. The first crop can be cut in early July and used for forage or silage, and from the stumps a second crop will be produced before the frosts in November. Feterita Feterita is a variety of Durra with erect heads, white seeds and black hulls. This variety is of recent introduction and shows super- iority over the Kafirs in drought resistance, and in shorter length Relation of Weather to Crops 79 of time required to produce a crop. Under favorable conditions and with an optimum water supply, a grain crop of feterita can be produced in 90 days. Under dry -farming Feterita is a very valuable crop for forage or grain, when necessaiy to plant as late as July. Early planting is not recommended for this crop under irrigation or dry-farming, unless two crops are desired in one ?eason. The Kafirs are superior for forage and where that is desired and planting car be done in March or April, they are to be preferred to Feterita. The greatest value of Feterita will come through its use as a dry- farming crop for summer planting. Shallu (Egyptian Wheat) Shallu is one of the broom corn sorghums. It is not extensively grown in Arizona. Some of it is grown under irrigation for chicken feed. As a forage plant it is not equal to the Kafirs or to the Milos. It was introduced from India. It is not recommended for dry land farming in this State. Under irrigation planting should be made in April and May. Kowliang Kowliang is another broom corn sorghum recently introduced from China and Manchuria. It will grow farther north than some other grain sorghums. Kowliang should be planted in April or INIay under irrigation, and as early as frost will permit under dry-farming. GRAPES The European, or vinifera, grape is admirably suited to the southern part of the State. Almost any of these vinifera varieties, including table, raisin, and wine grapes, will develop well, but in this State table grapes interest us more than the wine or raisin varieties. Our weather does not permit of raisin making in some seasons, and the law will not allow us to make wine. The char- acteristics of the European grape in our hot valleys are early ripen- ing and high sugar content. Our grapes become sweet before they are ripe, which results in too early picking by the grower. Successful European grape culture requires a long growing season, such as is generally found at elevations below 5000 feet in the southern half of the State, and under 4000 feet in the northern half of the State. Grapes will grow in a variety of soils and with moderate irrigation. An easily worked soil is preferred. Vines so Bulletin 78 should be set 6 by 8 or 8 by 8 feet apart. During the first two years the development of a single string trunk is desired, if the stump or self-supporting system of pruning is used. After the trunk is formed three or four arms are developed which carry the fruiting canes or spurs and the renewal spurs. vSubsequent pruning consists in thinning the canes to the required number and the shortening-in of these canes according to the variety; also the leaving of renewal spurs to form the fruiting wood for the next crop. The stump system has several disadvantages, but it is an easy one to establish and maintain and allows cultivation in tvvo direc- tions, which advantages make it the most popular system. It is better fitted to the varieties which bear well on spurs like the Mission, than to vaiieties like Thompson's Seedless, which need canes upon which to bear a full crop. A trellis is best for this and other long-pruned varieties. It has not as yet been necessary to graft vines in Arizona to resist the phylloxera. Insects are not very numerous, the Buffalo leaf hopper and the green beetles being the worst. Thompson's vSeedless is easily the most popular grape, because it ripens early enough to escape the green beetles and is seedless. Other popular varieties are Mission, Muscat, and Malaga. The Dattier de Eeyreuth, Almeria, Lady Finger, and Purple Damascus are also worthy of trial. In the cool sections of the State the American or American- European hybrid varieties of grapes can be grown. The best of these varieties for our conditions is Niagara. Other varieties are Aga- wam. Woodruff, and Concord. Although these varieties can be grown in ihe warm parts of the State, the vines aie not very healthy and the yield is low. GRASSES Brome grass, Kentucky blue grass, Australian rye grass, orchard grass, and other similar cultivated grasses so common in the Central and Eastern states are seriously injured or killed outright by our hot, dry summers at altitudes below 3000 feet. Tney make good growth, however, during nearly all of the fall, winter, and spring seasons. Seeds of such grasses should be sown in September jr early in October when the maximum temperatures are considerably lower than in summer. During June and July the seeds of these Relation of Weather to Crops 81 grasses will not germinate, ordinarily, even though given abundant irrigation. Johnson grass and Bermuda grass are considered by farmers to be the two chief weed pests of the region. Both are dormant in winter, but grow vigorously throughout the summer. Bermuda grass is a fair lawn grass and presents a good appearance during tlie heat of summer when blue grass is either dead or in very poor condition. A good combination for lawns for the warmer val- leys of the vState is Bermuda grass and Australian rye grass, the former for summer growing and the latter for winter and spring. Australian rye grass is an annual under our cliinatic conditions, and is sown thickly and raked into Bermuda grass sod in Sep- tember. With abundant irrigation it germinates readily and soon forms a velvety carpet which should be mowed during the winter and spring months. In early summer the rye grass dies out and is gradually replaced by Bermuda grass. White clover is used to some extent for lawn purposes. It endures a wide range of temperatures since it grows both in summer, when it requires abundant and heavy irrigation, and in winter. Like blue grass it grows best in partly shaded lawns at altitudes below 2500 feet. ^^bove altitudes of 3000 feet both these lawn plants grow well with most ordinary care. Lippia nodiflora, a member of the Verbena family, also grows well at lower altitudes for lawn purposes. • This is a low trailing plant with an abundance of small, whitish flowers resembling those of the whit-e clover. It will grow with less water than most other lawn plants and thrives in shallow soils that contain considerable broken caliche. It does best with moderate irrigation and should be cut with a lawn mower the same as lawn grasses. Rhodes grass and Sudan graSs have been introduced recently and are very promising as forage crops. Rhodes grass is believed to be native to southern Africa and is injured with winter tem- peratures of 5^ F. or lower. It spreads from its roots by means of stolons which grew above ground and in a single season it usually forms a continuous turf. There is no danger of its becoming a pest like Johnson grass since with one plowing it can be eradicated. It has not been grown in rich alluvial soils, but in ordinary mesa soil on the University grounds it has outyielded alfalfa several times, and with the most ordinary care makes a growth from early spring until late fall. Its heaviest growth appears to be made in July and August. 82 Bui.le;tin 78 Sudan grass very much resembles Johnson grass. It is an annual plant, however, and has no rootstocks or underground stems of any kind. Its yields are heavy and where it has been grown as a crop it has given satisfactory results. The forage is rather coarse though much relished by stock. It grows best during the hot summer weather and is quite drought resistant. During the summer of 1913, the yields of this plant at the Experiment Station Farm at Phoenix were at the rate of 8 tons per acre from two cut- tings. It also produces heavy crops of seed. This is desirable since the plant has to be sown annually. GUAVAS These tropical fruits are too sensitive to cold to be grown even in the warmest parts of the vState. The common guava requires some protection during our mildest winters. The strawberry guava is somewhat hardier, but even this can not be grown satis- factorily in the Salt and Lower Colorado River valleys. One should not plant out fruits as tender as the guava unless he is well prepared to care for them in winter. KAFIR AND EGYPTIAN CORN {See under Grain Sorghums) KOWLIANG (See under Grain Sorghums) LEMONS The cHmate of Arizona is not as well suited to the culture of lemons as to oranges. The lemon is more tender, and to produce continually, as a commercial crop should, requires an equable climate near the coast. In a very few places in the Salt River and Yuma valleys, where the mercury does not drop below 25° F., the lemon can be grown for local consumption. In these valleys it will not produce fruit in summer when the fruit is in greatest demand. Orchards should be heated when the temperature drops below 28° F. It is customary to start the heaters when the temperature gets a degree or two below freezing if it gets this cold before 12 or 1 o'clock a. m. The mercury generally falls until about 4 a. ni. on a still night. It is easier to keep the temperature of the trees at Relation of Weather to Crops 83 a given point by heating early than it is to raise the temperature after it has once fallen. Trees for home use should be planted in a protected place near buildings or other trees. The Eureka is the best market variety, but Villa Franca, Lisbon, and Sicily are good producers. LETTUCE Head lettuce is destined to become a commercial truck crop in Southern Arizona. It thrives in an arid climate if plenty of irrigating water is available. The quality of the crop can not bt surpassed when the right variety is grown. The growing conditions necessary for the production of lettuce are a cool growing season, ranging from not over 85° F. to not less than 20°; a rich, easily worked soil which will promote rapid growth: early thinning of the plants; frequent cultivation; and adequate irrigation, especially in warm weather. In the southern part of the State seed should be sow^n in plac^- any time from September to January. The plants should be thinned to 12 inches as soon as they have three or four leaves Delay in this checks the growth and increases the cost of the work. In cultivation, care should be exercised not to throw soil into the heads. A sandy soil is objectionable because the sand blows into the heads. Head lettuce can be had in the subtropical portions of the State from Thanksgiving until April. In cooler locations it is grown as an early spring crop. Hot weather causes lettuce to stop growing, become bitter, and send up a seed stalk. The varieties which succeed best are those with the crinkled leaves. New York or Los Angeles, Iceberg and Denver Market are of this type, named in the order of their popularity. The smooth-leaved lettuces, like Big Boston, Tennis Ball, Salamander. etc., are so much inferior in this climate to the other varieties named that it is not advisable to grow them. Cos or Romaine lettuce and varieties of loose-leaf lettuce also grow well, but are not to be compared with either New York or Iceberg. LOQUATS Loquats are easily grown in the valleys in the southern parts of the State, below altitudes of 2500 feet. They bloom from No- vember to January and, ordinarily, the flowers are killed by frost. 84 Bulletin 78 These trees are among the finest broad-leaf evergreens and are handsome ornamentals. When planted against a house or in protected situations the flowers and fruits are much less likely to be injured with frost, so that occasionally a good crop of fruit is produced. During the winter of 1912-1913 the foliage of loquats was not injured with a temperature of 6° F. Loquats are tolerant to our extreme heat and aridity, the foliage showing almost no bad effects in summer. MILLET Most varieties of millet can be grown readily, although the yield is not as great as in some cooler regions. The ordinary varieties are sown during August and harvested during the fall, as in other regions. German millet is most generally grown, being resistant to heat and drought. Pearl millet may be planted in the spring and will grow luxuriantly all summer, but does not seem as desirable for a forage crop as sorghum. MII.O ]MAiZE (See under Grain Sorghums) MULBERRIES Mulberries are easily grown here, nearly all varieties thriving under our conditions. Thev are amons: the earliest of our trees to leaf out and to ripen fruit. Mulberries would be very desir- able for shade trees were it not for the litter made by their fruit falling on the ground. This attracts flies and is annoying under- foot. Nurserymen are noM' propagating mulberries that are said to produce only staminate flowers. Such trees would be especially valuable for avenue pla-nting. The heavy fruiting mulberry trees are 'valuable for planting in poultry yards because of their densa shade and spreading branches among which poultry may roost. Hogs are also fond of mulberries. The most desirgble varieties for planting are the Downing Everbearing, New American White, Russian, and Persian or blatk mulberry. The Downing Ever bearing mulberr}^ has large long-pointed leaves that are dull green on the upper side. It is a form of Morns muUicaidis . The New American is a form of the white mulberry. Its leaves are glossy above, large, and short-pointed. The Russian mulberry is a ver}^ hardy form of the white mulberry, usually having deeply cut leaves. It does not grow as large as the white mulberry, but Relation of Weather to Crops 85 is hardy and is highly recommended ffc>r planting under dry farming conditions. The Persian mulberry branches from near the ground with stout, spreading limbs. The leaves are large and dull green. The fruits are broad and slightly hairy. When ripe they are black, juicy and tart, and are excellent for table use. MUSKMEIvONS (cANTALOUP'ES) The two terms are often used interchangeably, since there is no real distinction between them. In the West it is customary to call the small, round, netted melon the cantaloupe, and the large, oblong or flattened, netted or smooth melons, muskmelons. Both types are grow'n in the same way, the cantaloupe being far more popular than the muskmelon. The cantaloupe or muskmelon requires a rich loam soil, prefer- ably a sod soil, for its best development, a warm growing season, plenty of water, dr}^ air, and plenty of sunshine during the ripening period. The seed is planted as soon as danger of frost is over, the hills being placed about 4 to 6 feet apart with 8 to 12 seed placed in a hill along the water line of furrows to insure prompt germination. As soon as danger of insect damage to the seedlings is past, the plants are thinned to 2 or 3 in a hill. If the ground is foul with weeds or Bermuda grass the hills should be checked and cultivated in both directions. As the vines begin to run, the irrigation furrows should be moved away from the rows. The crop reaches maturity in from 80 to 120 days, depending on the weather and the variety. Plantings of cantaloupes made in July in the southern part of the State are profitable if the aphids or plant lice do not take the crop. These lice are very difficult to control and are nearly always present. Tobacco spray, if thoroughly applied every week before the lice appear, will generally keep them in subjection. The most popular varieties are Rockyford, Burrell's Gem, Nutmeg, Earty Waters and Early Hackensack. OATS {See under Grains) OLIVES Olives are peculiarly well adapted to southern Arizona con- ditions. They are never injured by our summer heat and very 86 Bulletin 78 rarely is the fruit injured by cold. On account of the bright sun- light and dryness of the atmosphere, the trees are free from the Scale insects which cause so much damage in moister climates. The trees grow vigorously, bear heavily, the fruit is large and the con- tent of oil is high. Some varieties mature their fruit in October and November, while others will hold their fruit in gojd condition for oil making until June of the following year. Olive culture, both for pickles and oil, promises to be one of the standard and profitable industries of the region. The varieties best suited for pickles are Mission, Manzanillo, and Sevillano. The varieties best suited for oil making are Mission, Correggiola, Nevadillo, Pendulina, and others. ONIONS This crop is easily gfown in southern Arizona as a winter crop, and in northern Arizona as a spring and summer crop. It is a profitable truck crop in most sections of the State, although prices may drop below the cost of production in June when growers are endeavoring to dispose of their entire crop at once. Bermuda, the type of onion best suited to this region, is not a good keeper, although when carefully handled and cured on racks in a house where sulphur may be burned, it will usually keep until fall. The cool valleys in the northern part of the State should produce onions for southern markets from fall until June. The supply at present comes from California. The method of growing generally employed in the southern part of the State, is to sow the seed in seed-beds between August and October, and when the plants are the size of a lead pencil transplant into narrow borders which can be flooded. They are set 2 to 4 inches apart in rows 12 to 14 inches apart. With efficient management the cost of growing the plants and trans- planting them need not exceed $35 per acre. Some growers prefer to sow the seed in place, planting two rows on a ridge. To avoid thinning with this method, an accurate knowledge of the viability of the seed and a careful adjustment of the seeder is necessary. Growers in the northern valleys who wish to raise onions by the transplanting method, should arrange with a gardener in the Salt River Valley to grow their plants out of doors. Otherwise they should be grown in hotbeds, which is a more expensive method. A good loam st)il, preferably enriched with rotted manure, well leveled, cultivated with a wheel hoe at frequent intervals, and irrigated as required, are essential to a successful crop. Relation of Weather to Crops 87 Crystal Wax, WhiteBermuda, Yellow and Red Bermuda, and Aus- tralian Brown are the most popular varieties. Australian Brown is the best keeper, but it is not a sure crop in the warmest valleys. Yellow Danvers is successfully grown in the cool sections. oranges While oranges are being grown to an increasing extent on the upper slopes of the Salt River Valley, on the mesa near Yuma, and in some other localities, the area in Arizona where their culture may be profitably engaged in is quite Hmited when compared with the total of cultivated land. Orange trees being semitropical ever- greens are severely injured when the mercury falls to 20'', and 16° ' will often kill the trees to the ground. The intense heat of summer is also very apt to injure the trunks unless the trees are headed low and properly pruned. For these reascis orange culture re- quires more skill and is attended with somewhat greater expense than in other orange growing localities. The incentive to grow oranges in a commercial way under these conditions is the high price received in the eastern markets for the Washington Navel variety, which ripens its fruit somewhat in advance of the California crop. Partly on account of the hot dry climate citrus trees are not at present infested with scale insetts. The chief insect enemies of the orange are several species of thrips of which EiUhrips tritici is by far the most common. They distort the foliage and scar the fruit with considerable detriment to its selling value. Washington Navel is perhaps the most profitable vaiiety. Valencia, Ruby, St. Michaels, Jaffa, and Alediterranean Sweet are also grown. peaches The different varieties of peaches differ considerably in their relation to the climatic conditions of the region. vSome varieties escape injury from frosts most seasons and endure well the heat of summer. These varieties belong mostly to the Chinese type of peaches, blooming so early during the winter that the young fruit has attained sufficient size to endure quite low temperatures. As a result they set full of fruit every year. Other varieties not only receive considerable injury from spring frosts, but do not endure well the heat of summer. Peach trees are longer lived than apple •or plum trees, but not so long-lived as either apricots or almonds 88 Bulletin 78 usually remaining productive ten or twelve years from time of setting. On account of the prevalence of spring frosts peaches are a ver^- uncertain crop in exposed situations in the mountains. vSome varieties of peaches are seriously injured by thrips which attack the winter buds just as they are unfolding in the spring. Those varieties which ripen their crop in the middle of the heated season suffer seriously from the Allorhina beetle. Ripe peaches are also very difficult to handle and market during very hot weather. The chief disease of the peach in Arizona is the crown gall of the roots which often does very serious damage (See Ariz. Sta. Bull. 33). Very few peaches are dried in the region for the same reason as given under "Figs." A very large list of peaches does well in the southern, valleys, among which the following have been found to be especially desirable: Admiral Dewey, Alexander, Briggs May, Late Crawford, Elberta, vSalway, Wheatland, Sylphide Cling, Krummel, vSt. John and Belle of Georgia. PEANUTS Peanuts ma}- be grown in the lower irrigated valleys. They should be planted as soon as danger of frost is over; and mature five or six months after planting. They do best in sandy soils, recjuire frequent irrigation and should be harvested as soon as yellow vines indicate maturity, to avoid sprouting the crop. The Spanish variety yields a heavy crop of small nuts. Virginia Red produces well if sufficiently irrigated. Indian Runner yields under less favorable conditions than Virginia Red. In addition to their uses as human food, peanuts make excellent hay. Being leguminous in character, the crop is beneficial to the soils upon which it is grown. PEARS Pears are well suited to all parts of Arizona, except in the very frosty mountain sections. They thrive in a heavy soil, bloom late com- pared with the stone fruits, and so usually escape damage by frost. On account of late bloomiftg the pear can be planted in valleys where other fruits are less certain, and where the pear finds soil conditions better than on uplands where the soil is lighter. The fire blight, which is so destructive in practically all pear- growing sections, is not so severe in our arid climate as it is in humid sections. Nevertheless, it can do very severe damage in this State, Relation of Weathkr to Crops 73 injured, one to four inches of the tips being killed. December 14, 1901, slight injury was done to the tips of E. rudis and E. leucoxylon, while vear old plants of E. rostrata were nearly all frozen to the ground, the minimum thermometers registering 15° F. at the ground, 20° F. in tl:-.- go\ernn-cnt shelter, and 24' F. at the Weather Bureau. All are n ore or less checked in their growth by the heat of midsummer, E. pilyanihcjiia being affected perhaps the least of any cf the speci^-S mentioned. vSome species grow best in a moist atmosphere, but m-ost of them prefer a dry atm-osphere. With mod- erate irrigation, the Eucalypts noted above will endure well our hot, dry atmosphere. Eucalypts may be grown from seed in a frame lattice house, the sides of which should be more or less protected with vines. The seeds should be sown by the middle of April or early in May in flats containing about 3 inches of clean fine sand. They should be scattered on the surface and covered with a thin layer of sand. The water used in irrigating should be free from alkali and the flats should be covered with one or two thicknesses of newspaper uniil the seedlings are mostly up. They must not be kept too wet, other- wise they will be attacked by a damping-ofi fungus. When th^ small plants have 4 or 0 leaves they may be transplanted in flats containing 5 or 6 inches cf fine, sandy, loamy soil; and they should l;e watered regularly. About 100 plants may be set in a flat 12 by 20 inches in size. From July 1 to August 15 the flats of seedlings should be covered with fine wire screen or mosquito netting to keep June and GoldsmJth beetles from depositing their eggs in the moist soil. The larvae of these insects eat the rootlets cf young Eucalypts and may do a great amount of damage in a short time. The Eucalypts may remain in the lattice house during the winter season and be set out the following spring. Eucalypts, like citrus trees, have two periods of thrifty growth, one from March to June, and the other from the latter part of August to the latter part of November. A little growth is made here by a few species during the hottest weather of summer, and a few make some growth during the coldest weather of winter. The most rapid growing Eucalypt {E. globulus) does not endure well our extremes of climate, but the growth of E. rudis, E. tereti- corniSy and E. rostrata is fairly rapid. Judging by their growth upon the Farm and elsewhere, they can be counted on to attain a height of 30 feet and a diameter of 6 inches in four or five years, and a height of 50 feet and a diameter of 1 foot in six or eight years. A five-vear-old E. rudis at the Farm measured 1 foot in diam- 74 Bulletin 78 t weather of winter is over, but most other grains begin stooling earlier, if sown during early fall. Grain sown during the latter part of January and during February makes an uninter- rupted growth from the time of germination, and matures before the weather becomes extremely hot. Grain sown later then Feb- ruary does not have sufficient timxe'for full growth before the hot weather of May and June. November is ordinarily the most fa\orable month for sowing grain. Evaporation being compara- tively slow during the weather that follows, grain sown in moist soil during this month usually needs no irrigation until February or March if there is an average amount of winter rainfall. All sowings of all varieties ordinarily ripen during May or the ie\x days that precede or follow this month. At this time of year the Meather is usually very fa\orable for harvesting of the crop. The principal grains sown are barley and wheat, though oats and rye are also successfully grown, but to a much smaller extent. The yield of grain is from 1500 to 3000 pounds per acre, depending upon the soil and water supply. The white varieties such as Sonora, Early Eaart and White Australian are chiefly grown, although durum wheats produce well. Macaroni is probably th^.^ heaviest yielder, but is not used by the millers. Where grain is grown for poultry or stock feed, macaroni wheat is to be pre- ferred. Among the bread wheats, Early Baart, a variety intro- duced by the Experiment Station about the year 1900, is now preferred by the millers on account of its high quality. It is now the most widely grown variety in the State. Marquis and Turkey Red will do well at the higher altitudes. Relation of Weather to Crops 77 All varieties of barley do well. The variety of oats most widely grown is Texas Red. For winter pasturage and an early crop of hay, barley, wheat, and oats are grown instead of the grasses used in cooler regions. These grains are sown both upon the fields of alfalfa and in freshly plowed soil. In the former case the seed is covered with a disk harrow. In fresh soil the seed is either disked or harrowed in. When sown upon alfalfa fields, seeding is usually done during early fall. In fresh soil seeding is done throughout fall and early winter. The resulting growth is commonly pastured during winter, and then permitted to grow up for hay during spring, being cut in April and May, when the kernels are quite well formed. Oats make the best hay, and they are now sown for this purpose more gen- erally than formerly. The usual yield of grain hay is one and a half to three tons per acre. GRAIN SORGHUMS The sorghums are divided into two classes — the saccharine, used for syriip making or for forage, knd the non-saccharine or grain sorghums, used for grain and forage. The grain sorghums are of tropical origin, and flourish best in hot climates. They are very drought resistant, and well adapted to the semi-arid Southwest. They develop well with eight to ten inches of rainfall during the growing season. Grain sorghums are divided into three classes, according to the character of head: 1. Kafir, with compact, erect heads. 2. Durra, with compact, pendant heads. 3. Broom corn type, with loose spreading heads. The varieties of grain sorghums profitably grown in Arizona that belong to these classes are as follows: Black-hull white Kafirs, dw^arf and standard. White milo or durra. \ ellow milo, usually called Milo Maize, dwarf and standard. Feterita, one of the Durras. . Shallu, a broom corn type, sometimes called Egyptian wheat. Kowliang, another broom corn type. Kafir The Kafirs, of which there are three varieties, the White, the Red, and the black hulled White, are very drought resistant. They 78 Bulletin 78 were introduced from South Africa and will endure for extended periods awaiting rainfall, without apparent injury to the plant. As soon as moisture is supplied Kafir will renew its growth and continue to mature its grain. The growing season for Kafir is about 120 days, or longer when growth is arrested by insufficient moisture. The date of planting in both irrigated and dry-farming sections should be as early as late spring frosts will permit. Under dry- farming conditions in the southern part of the State it is well to put the crop in as early as March 10 to 15 in order to take advantage of winter moisture. Black-hull White Kafir is the most popular variety grown in Arizona both for grain and silage purposes. Milo Maize The term Durra is so little used that this group is considered as Milo Maize. The Durras include white, brown and yellow miles and are characterized by large flat seeds. Feterita, a more recent introduction, also belongs to the Durra group. This group of grain sorghums was introduced from North Africa. Like Kafir, Milo Maize flourishes in the hot dry climate of Arizona. The time required to produce a crop of yellow milo is about 100 days or nearly three weeks shorter then Kafir. The Milos are better grain producers than the Kafirs, but are not as good forage crops. Dwarf types of milo have been developed superior to the tall cr standard types for production of grain. Under dry-farming condi- tions the Milos should be planted in July in southern Arizona. The summer rains begin at this time and the season is long enough after that date to mature a crop. In the northern part of the State, where these crops are grown by dry-farming, planting should be made about May 1. In the irrigated sections the Milos should be planted in April. Two crops of milo can be harvested from the April planting. The first crop can be cut in early July and used for forage or silage, and from the stumps a second crop will be produced before the frosts in November. Feterita Feterita is a variet}' of Durra with erect heads, white seeds and black hulls. This variety is of recent introduction and shows super- iority over the Kafirs in drought resistance, and in shorter length Relation of Weather to Crops 79 of time required to produce a crop. Under favorable conditions and with an optimum water supply, a grain crop of feterita can be produced in 90 days. Under dry-farming Feterita is a very valuable crop for forage or grain, when necessaiy to plant as late as July. Early planting is not recommended for this crop under irrigation or dry-farming, unless two crops are desired in one reason. The Kafirs are superior for forage and where that is desired and planting car be done in March or April, they are to be preferred to Feterita. The greatest value of Feterita will come through its use as a dry- farming crop for summer planting. Shallu (Egyptian Wheat) Shallu is one of the broom corn sorghums. It is not extensively grown in Arizona. Some of it is grown under irrigation for chicken feed. As a forage plant it is not equal to the Kafirs or to the Milos. It was introduced from India. It is not recommended for dry land farming in this State. Under irrigation planting should be made in April and May. Kowliang Kowliang is another broom corn sorghum recently introduced from China and Manchuria. It will grow farther north than some other grain sorghums. Kowliang should be planted in April or May under irrigation, and as early as frost will permit under dry-farming- GRAPES The European, or vinifera, grape is admirably suited to the southern part of the State. Almost any of these vinifera varieties, including table, raisin, and wine grapes, will develop well, but in this State table grapes interest us more than the wine or raisin varieties. Our weather does not permit of raisin making in some seasons, and the law will not allow us to make wine. The char- acteristics of the European grape in our hot valleys are early ripen- ing and high sugar content. Our grapes become sweet before they are ripe, which results in too early picking by the grower. Successful European grape culture requires a long growing season, such as is generally found at elevations below 5000 feet in the southern half of the State, and under 4000 feet in the northern half of the State. Grapes will grow in a variety of soils and with moderate irrigation. An easily worked soil is preferred. Vines 80 Bulletin 78 should be set 6 by 8 or 8 by 8 feet apart. During the first two years the development of a single string trunk is desired, if the stump or self-supporting system of pruning is used. After the trunk is formed three or four arms are developed which carry the fruiting canes or spurs and the renewal spurs. Subsequent pruning consists in thinning the canes to the required number and the shortening-in of these canes according to the variety; also the leaving of renewal spurs to form the fruiting wood for the next crop. The stump system has several disadvantages, but it is an easy one to establish and maintain and allows cultivation in two direc- tions, which advantages make it the most popular system. It is better fitted to the varieties which bear well on spurs like the Mission, than to vaiieties like Thompson's Seedless, which need canes upon which to bear a full crop. A trellis is best for this and other long-pruned varieties. ft has not as yet been necessary to graft vines in Arizona to resist the phylloxera. Insects are not very numerous, the Buffalo leaf hopper and the green beetles being the worst. Thompson's Seedless is easily the most popular grape, because it ripens early enough to esoape the green beetles and is seedless. Other popular varieties are Mission, Muscat, and Malaga. The Dattier de Beyreuth, Almeria, Lady Finger, and Purple Damascus are also worthy of trial. In the cool sections of the vState the American or American- European hybrid varieties of grapes can be grown. The best of these varieties for cur conditions is Niagara. Other varieties are Aga- wam. Woodruff, and Concord. Although these varieties can be grown in the warm parts of the State, the vines aie not very health}^ and the yield is low. GRASSES Brome grass, Kentucky blue grass, Australian rye grass, orchard grass, and other similar cultivated grasses so common in the Central and Eastern states are seriously injured or killed outright by our hot, dry summers at altitudes below 3000 feet. Tney make good growth, however, during nearly all of the fall, winter, and spring seasons. Seeds of such grasses should be sown in September or early in October when the maximum temperatures are considerably lower than in summer. During June and July the seeds of these Relation of Weather to Crops 81 grasses will not germinate, ordinarily, even though given abundant irrigation. Johnson grass and Bermuda grass are considered by farmers to be the two chief weed pests of the region. Both are dormant in winter, but grow vigorously throughout the summer. Bermuda grass is a fair lawn grass and presents a good appearance during t!ie heat of summer when blue grass is either dead or in verv poor condition. A good combination for lawns for the warmer val- leys of the vState is Bermuda grass and Australian rye grass, the former for summer growing and the latter for winter and spring. Australian rye grass is an annual under our climatic conditions, and is sown thickly and raked into Bermuda grass sod in Sep- tember. With abundant irrigation it germinates readily and soon forms a velvety carpet which should be mowed during the winter and spring months. In early summer the rye grass dies out and is gradually replaced by Bermuda grass. White clover is used to some extent for lawn purposes. It endures a wide range of temperatures since it grows both in summer, when it requires abundant and heavy irrigation, and in winter. Like blue grass it grows best in partly shaded lawns at altitudes below 2500 feet. Above al-^ltudes of 3000 feet both these lawn plants grow well with most ordinary care. Lippia nodiflora, a member cf the V^erbena family, also grows well at lower altitudes for lawn purposes. This is a low trailing plant with an abundance of small, whitish flowers resembling those of the white clover. It will grow with less water than most other lawn plants and thrives in shallow soils that contain considerable broken caliche. It does best with moderate irrigation and should be cut with a lawn mower the same as lawn grasses. Rhodes grass and Sudan graSs have been introduced recently and are very premising as forage crops. Rhodes grass is believed to be native to southern Africa and is injured with winter tem- peratures of 5^ F. or lower. It spreads from its roots by means of stolons which grow above ground and in a single season it usually forms a continuous luif. There is no danger of its becoming a pest like Johnson grass since with one plowing it can be eradicated. It has not been grown in rich alluvial soils, but in ordinary mesa soil on the University grounds it has outyielded alfalfa several times, and with the most ordinary care makes a growth from early spring until late fall. Its heaviest growth appears to be made in July and August. 82 Bulletin 78 Sudan grass very much resembles Johnson grass. It is an annual plant, however, and has no rootstocks or underground stems of any kind. Its yields are heavy and where it has been grown as a crop it has given satisfactory results. The forage is rather coarse though much relished by stock. It grows best during the hot summer weather and is quite drought resistant. During the summer of 1913, the yields of this plant at the Experiment vStation Farm at Phoenix were at the rate of 8 tons per acre from two cut- tings. It also produces heavy crops of seed. This is desirable since the plant has to be sown annually. GUAVAS These tropical fruits are too sensitive to cold to be grown even in the warmest parts of the vState. The common guava requires some protection during our mildest winters. The strawberry guava is somewhat hardier, but even this can not be grown satis- factorily in the Salt and Lower Colorado River valleys. One should not plant out fruits as tender as the guava unless he is well prepared to care for them in winter. KAFIR AND EGYPTIAN CORN {See under Grain Sorghums) KOWLIANG {See under Grain Sorghums) LEMONS The climate of Arizona is not as well suited to the culture of lemons as to oranges. The lemon is more tender, and to produce continually, as a commercial crop should, requires an equable climate near the coast. In a very few places in the Salt River and Yuma valleys, where the mercury does not drop below 25° F., the lemon can be grown for local consumption. In these valleys it will not produce fruit in summer when the fruit is in greatest demand. Orchards should be heated when the temperature drops below 28° F. It is customary to start the heaters when the temperature gets a degree or two below freezing if it gets this cold before 12 or 1 o'clock a. m. The mercury generally falls until about 4 a. ra. on a still night. It is easier to keep the temperature of the trees at RbivATion of Weather to Crops 83 a given point by heating early than it is to raise the temperature after it has once fallen. Trees for home use should be planted in a protected place near buildings or other trees. The Eureka is the best market variety, but Villa Franca, Lisbon, and vSicily are good producers. EETTucE Head lettuce is destined to become a commercial truck crop in Southern Arizona. It thrives in an arid climate if plenty of irrigating water is available. The quality of the crop can not be surpassed when the right variety is grown. The growing conditions necessary for the production of lettuce are a cool growing season, ranging from not over 85° F. to not less than 20°; a rich, easily worked soil which will promote rapid growth; early thinning of the^ plants; frequent cultivation; and adequate irrigation, especially in warm weather. In the southern part of the State seed should be sown in plad^ any time from September to January. The plants should be thinned to 12 inches as soon as they have three or four leaves Delay in this checks the growth and increases the cost of the work. In cultivation, care should be exercised not to throw soil into the heads. A sandy soil is objectionable because the sand blows into the heads Head lettuce can be had in the subtropical portions of the State from Thanksgiving until April. In cooler locations it is grown as an early spring crop. Hot weather causes lettuce to stop growing, become bitter, and send up a seed stalk. The varieties which succeed best are those with the crinkled leaves. New York or Los Angeles, Iceberg and Denver Market are of this type, named in the order of their popularity. The smooth-leaved lettuces, Hke Big Boston, Tennis Ball, Salamander, etc., are so much inferior in this climate to the other varieties named that it is not advisable to grow them. Cos or Romaine lettuce and varieties of loose-leaf lettuce also grow well, but are not to be compared with either New York or Iceberg. I.OQUATS Loquats are easily grown in the valleys in the southern parts of the State, below altitudes of 2500 feet. They bloom from No- vember to January and, ordinarily, the flowers are killed by frost. 84 Bulletin 78 These trees are among the finest broad-leaf evergreens and are handsome ornamentals. When planted against a house or in protected situations the flowers and fruits are much less likely to be injured with frost, so that occasionally a good crop of fruit is produced. During the winter of 1912-1913 the foliage of loquats was not injured with a temperature of 6° F. Loquats are tolerant to our extreme heat and aridity, the foliage showing almost no bad effects in summer. MILLET Most varieties of millet can be grown readily, although the yield is not as great as in some cooler regions. The ordinary varieties are sown during August and harvested during the fall, as in other regions. German millet is most generally grown, being resistant to heat and drought. Pearl millet may be planted in the spring and will grow luxuriantly all summer, but does not seem as desirable for a forage crop as sorghum. MILO MAi/E (See under Grain Sorghums) MULBERRIES Mulberries are easily grown here, nearly all varieties thriving under our conditions. They are among the earliest of our trees to leaf out and to ripen fruit. Mulberries w^ould be very desir- able for shade trees were it not for the litter made by their fruit falling on the ground. This attracts flies and is annoying under- foot. Nurserymen are now propagating mulberries that are said to produce only staminate flowers. Such trees would be especially valuable for avenue planting. The heavy fruiting mulberry trees are valuable for planting in poultry 3^ards because of their dense shade and spreading branches among which poultry ma^^ roost. Hogs are also fond of mulberries. The most desirable varieties for planting are the Downing Everbearing, New Am.erican White, Russian, and Persian or blatk mulberry. The Downing Ever bearing mulberry has large long-pointed leaves that are dull green on the upper side. It is a form of Moms multicaulis . The New American is a form of the white mulberry. Its leaves are gloss}' above, large, and short-pointed. The Russian mulberry is a ver}' hardy form cf the white mulberry, usually having deeply cut leaves. It does not grow as large as the white mulberry, but Relation of Weather to Crops 85 is hardy and is highly recommended for planting under dry farming conditions. The Persian mulberry branches from near the ground with stout, spreading limbs. The leaves are large and dull green. The fruits are broad and slightly hairy. When ripe they are black, juicy and tart, and are excellent for table use. MUSKMELONS (cANTALOUP'ES) The two terms are often used interchangeably, since there is no real distinction between them. In the West it is customary to call the small, round, netted melon the cantaloupe, and the large, oblong or flattened, netted or smooth melons, muskmelons. Both types are grown in the same way, the cantaloupe being far more popular than the muskmelon. The cantaloupe or muskmelon recjuires a rich loam soil, prefer- ably a sod soil, for its best development, a warm growing season, plenty of water, dry air, and plenty of sunshine during the ripening period. The seed is planted as soon as danger of frost is over, the hills being placed about 4 to 6 feet apart with 8 to 12 seed placed in a hill along the water Hne of furrows to insure prompt germination. As soon as danger of insect dam.age to the seedlings is past, the plants are thinned to 2 or 3 in a hill. If the ground is foul with weeds or Bermuda grass the hills should be checked and cultivated in both directions. As the vines begin to run, the irrigation furrows should be moved away from the rows. The crop reaches maturity in from SO to 120 days, depending on the weather and the variety. Plantings of cantaloupes made in July in the southern part of the State are profitable if the aphids or plant lice do not take the crop. These lice are very difficult to control and are nearly always present. Tobacco spray, if thoroughly applied every week before the lice appear, will generally keep them in subjection. The most popular varieties are Rockyford, Burrell's Gem, Nutmeg, Early Waters and Early Hackensack. OATS {See under Grains) OLIVES Olives are peculiarly well adapted to southern Arizona con- ditions. They are never injured by our summer heat and very 86 Bulletin 78 Tarely is the fruit injured by cold. On account of the bright sun- light and dryness of the atmosphere, the trees are free from the Scale insects which cause so much damage in moister climates. The trees grow vigorously, bear heavily, the fruit is large and the con- tent of oil is high. Some varieties mature their fruit in October and November, while others will hold their fruit in good condition for oil making until June of the following year. Olive culture, both for pickles and oil, promises to be one of the standard and profitable industries of the region. The varieties best suited for pickles are Mission, Manzanillo, and vSevillano. The varieties best suited for oil making are Mission, Correggiola, Nevadillo, Pendulina, and others. ONIONS This crop is easily grown in southern Arizona as a winter crop, and in northern Arizona as a spring and summer crop. It is a profitable truck crop in most sections of the State, although prices may drop below the cost of production in June when growers are endeavoring to dispose of their entire crop at once. Bermuda, the type of onion best suited to this region, is not a good keeper, although when carefully handled and cured on racks in a house where sulphur may be burned, it will usually keep until fall. The cool vallej-s in the northern part of the State should produce onions for southern markets from fall until June. The supply at present comes from California. The method of growing generally employed in the southern part of the State, is to sow the seed in seed-beds between August and October, and when the plants are the size of a lead pencil transplant into narrow borders which can be flooded. They are set 2 to 4 inches apart in rows 12 to 14 inches apart. With efficient management the cost of growing the plants and trans- planting them need not exceed $35 per acre. Some growers prefer to sow the seed in place, planting two rows on a ridge. To avoid thinning with this method, an accurate knowledge of the viability of the seed and a careful adjustment of the seeder is necessary. Growers in the northern valleys who wish to raise onions by the transplanting method, should arrange with a gardener in the Salt River Valley to grow their plants out of doors. Otherwise they should be grown in hotbeds, which is a more expensive method. A good loam st)il, preferably enriched with rotted manure, well leveled, cultivated with a wheel hoe at frequent intervals, and irrigated as required, are essential to a successful crop. Relation of Weather to Crops 87 Crystal Wax, WhiteBermuda, Yellow and Red Bermuda, and Aus- tralian Brown are the most popular varieties. Australian Brown is the best keeper, but it is not a sure crop in the warmest valleys. Yellow Danvers is successfully grown in the cool sections. oranges While oranges are being grown to an increasing extent on the ■upper slopes of the Salt River Valley, on the mesa near Yuma, and in some other localities, the area in Arizona where their culture may be profitably engaged in is quite limited when compared with the total of cultivated land. Orange trees being semitropical ever- greens are severely injured when the mercury falls to 20', and 16" will often kill the trees to the ground. The intense heat of summer is also very apt to injure the trunks unless the trees are headed low and properly pruned. For these reasciis orange culture re- quires more skill and is attended with somewhat greater expense than in other orange growing localities. The incentive to grow oranges in a commercial way under these conditions is the high price received in the eastern markets for the Washington Navel variety, which ripens its fruit somewhat in advance of the California crop. Partly on account of the hot dry climate citrus trees are not at present infested with scale insetts. The chief insect enemies of the orange are several species of thrips of which Euthrips tritici is b}^ far the most common. They distort the foliage and scar the fruit with considerable detriment to its selling value. Washington Navel is perhaps the most profitable vaiiety. Valencia, Ruby, St. Michaels, Jaffa, and Mediterranean Sweet are also grown. PEACHES The different varieties of peaches differ considerably in their relation to the climatic conditions of the region. vSome varieties escape injury from frosts most seasons and endure well the heat of summer. These varieties belong mostly to the Chinese type of peaches, blooming so early during the winter that the young fruit has attained sufficient size to endure quite low temperatures. As a result they set full of fruit every year. Other varieties not only receive considerable injury from spring frosts, but do not endure well the heat of summer. Peach trees are longer lived than apple or plum trees, but not so long-lived as either apricots or almonds^ 88 Bulletin 78 usually remaining productive ten or twelve years from time of setting. On account of the prevalence of spring frosts peaches are a ver}- uncertain crop in exposed situations in the mountains. vSome varieties of peaches are seriously injured by thrips which attack the winter buds just as they are unfolding in the spring. Those varieties which ripen their crop in the middle of the heated season suffer seriously from the AUorhina beetle. Ripe peaches are 'also very difficult to handle and market during very hot weather. The chief disease of the peach in Arizona is the crown gall of the roots which often does very serious damage (See Ariz. Sta. Bull. 33). Very few peaches are dried in the region for the same reason as given under "Figs." A very large list of peaches does well in the southern, valleys, among which the following have been found to be especially desirable: Admiral Dewey, Alexander, Briggs May, lyate Crawford, Elberta, Salwa}', Wheatland, Sylphide Cling, Krummel, St. John and Belle of Georgia. PEANUTS Peanuts may be grown in the lower irrigated valleys. They should be planted as soon as danger of frost is over; and mature five or six months after planting. They do best in sandy soils, require frequent irrigation and should be harvested as soon as yellow vines indicate maturity, to avoid sprouting the crop. The Spanish variety yields a heavy crop of small nuts. Virginia Red produces well if sufficiently irrigated. Indian Runner yields under less favorable conditions than Virginia Red. In addition to their uses as human food, peanuts make excellent hay. Being leguminous in character, the crop is beneficial to the soils upon which it is grown. PEARS Pears are well suited to all parts of Arizona, except in the very frosty mountain sections. They thrive in a heavy soil, bloom late com- pared with the stone fruits, and so usually escape damage by frost. On account of late bloomifig the pear can be planted in valleys where other fruits are less certain, and where the pear finds soil conditions better than on uplands where the soil is lighter. The fire blight, which is so destructive in practically all pear- growing sections, is not so severe in our arid climate as it is in humid sections. Nevertheless, it can do very severe damage in this State, Relation of Weather to Crops 89 especially in overfertilized or overirrigated soil. The blight attacks new, fast-growing tissue, and works down into the tree, causing cankers. No spray will check it. Every eflfort should be made to induce a stocky, conservative growth. The pruning out of infected parts below the infection is of very doubtful benefit, unless a section is in a position to enforce a rigid inspection of every pear tree in the agricultural district. There are few examples where this has been done with success. There is only one pear in Arizona that will not blight. That is the Prickly Pear. Kieffer and Garber are less susceptible than varieties of French origin, but the quality of these Chinese pears is so poor that they are not grown unless the blight is very bad. The Bartlett is the most popular commercial variety. Other good varieties are jNIadeleine, Clapp's Favorite, I^e Conte, Winter Nelis, and Patrick Barry. PEAS Peas are produced in abundance in the gardens of Arizona during the cool part of the year. They will stand temperatures of 22° to 25"^ without serious injury if they are not growing very rapidly. Heavy frost will kill the blossoms of most varieties. In the Yuma Valley it is warm enough for peas to bear most of the winter, but in most parts of the State they can be grown either as a fall or as a spring crop. Some of the hardier smooth peas may be carried over winter without being damaged. The best time to grow peas in any part of the vState is as a very early spring crop, planting being done between January 1 (or earlier) and April 15, according to locality. Deep planting, 3 to 5 inches, is advisable, especially in the early fall, when peas rot badly if near the surface. Planting of dwarf varieties in double rows 10 to 12 inches apart, or in broad rows of 8 to 10 inches, allows the vines to support themselves, making cultivation and picking easier. The standard varieties are little grown because of the trouble and expense of supporting the vines. PECANS A few pecan trees are being cultivated in the Verde, Salt River, and Lower Colorado valleys. They thrive best in deep, rich soils with an abundance of irrigation. With proper culture they should grow successfully at altitudes of 5000 to GOOO feet. They seem to 90 Bulletin 78 endure well the summer heat in the lower valleys. The culture of pecans will probably never be successful commercially in Arizona, but it will be possible to grow them as ornamental and shade trees and to produce nuts of good quality for family use. The most suit- able varieties of pecans for our conditions are Texas Prolific or Sovereign, San Saba, Colorado, and Frotscher. p'ersimmons The common American persimmon (Diospyros virginiana) occa- sionally may be found under cultivation in the southern parts of the State. It withstands our summer heat very well if planted in deep alluvial soil and given moderate irrigation. It should thrive even better in the northern parts of Arizona where conditions of tempera- ture are more nearly like those of its native habitat. The culture of Japanese persimmons has not yet gone far enough to justify planting them on an extensive scale. The individual trees scattered about the vState seem to succeed well, but as yet they have not borne fruits. PLUMS At a very few situations in the mountains of Arizona nearly all varieties of plums succeed. In the hot southern valleys only certain kinds are profitable. These embrace certain varieties of the Ameri- can and Japanese classes. A few of the European varieties will endure the summers for a few years and produce a fairly good quality of fruit, but most of them are short-lived. While prunes may be grown, they are not profitable on a commercial scale in the southern valleys. Plums are injured much more by the heat of summer than by the spring frosts, the buds, blossoms, or young fruit rarely being injured seriously by frost. The only season during the past ten years when much injury was done was March 13, 1901, when the mercury fell to 32° in the government shelter, and 37'^ at the Weather Bureau. The various varieties of plums endure the summer con- ditions quite differently, the European varieties being most sensitive to heat. Those enduring heat best belong to the Japanese group, and most of those belonging to the Americ^an group endure summer fairly well. Unless the trees are headed low, the trunks are apt to be injured on the south and southwest sides, the trees dying later. The life of plum trees varies with the variety, that of desirable ones ranging from eight to twelve years. Plums are also subject to the Relation of Weather to Crops 91 crown gall disease, though to a less extent than almonds and peaches. Some varieties, especially the American, are greatly injured by thrips which damage the winter buds to such an extent that the trees leaf out late and many of the branches die. Varieties especially suited to the hot valleys are Red June, Doris, Mariana (for jelly), Burbankz Chalco, Climax, and W'ickson. POMEGRANATES All varieties of pomegranates are especially suited to the hot dry cHmate of the southern valleys. They are not injured either by the cold of winter or the heat of summer. Although they require irrigating water to enable them to bear profitable crops, well- established plants will remain alive and make some growth for many years with no other water than the natural rainfall. They are especi- ally resistant to alkali and, all things taken into consideration, pome- granates are one of the surest crops of the region. The pomegranate is subject to but two serious troubles — a core rot and a splitting of the fruit, neither of which is at present well understood. On account of the fact that this fruit is but little known in northern markets, the demand is at present small, only a few orchards being in existence. Pomegranates are grown commonly throughout the southern part of the State as hedges, and shrubs for garden and lawn. Considerable fruit gathered from hedges is utilized by the Mexican portion of the local population. While all the varieties succeed admirably, the Wonderful excels all that have been so far tested, in size, beauty, and quality. POMELOS (grape fruit) Districts which can produce oranges can produce pomelos. There is no radical difference between the culture of these two trees. The quarantine in Arizona and California on all citrus fruits from the Gulf States should give an impetus to pomelo culture in Arizona, since the quality of the Arizona fruit is superior to that of California. In fact, the best fruit produced at Yuma is little, if any, lower in qual- ity than the Florida product. The training and pruning of the pomelo consists in retaining only the strong branches of young trees which have been "headed" at approximately 3 feet when set out. Interfering and dead branches are removed and the growth of watersprouts is discouraged. 92 Bulletin 78 The best variety at present grown is the Marsh or Marsh's Seedless. It is probable that the poor quality of much of the western fruit is due, in a large measure, to the necessity of growing varieties poorly adapted to our conditions. Arantium, Duncan, and Triumph are sometimes grown. POTATOES But a very small proportion of the Irish potatoes consumed in Arizona is produced within the State. This is due to the fact that except at a few specially favored localities in the mountains, where irrigating water is available, potatoes are grown with con- siderable difficulty. While not easily grown in the hot southern valleys, they do moderately well when the methods that it is essen- tial to follow for their successful culture are understood. Being sensitive both to the frosts of winter and the heat of summer, they can be grown only during late winter and early spring, and during the fall. For the spring crop they are planted during the latter part of January or the early part of February, and mature about the first of June. For a fall crop they are planted during the latter part of August or the first few days of September. The fall crop does not always fully mature before the frosts of November, but usually furnishes a limited supply of young potatoes for the table. The following additional remarks apply especially to the Salt River and Colorado River valleys. With the exception of possibly a month in summer and al)out two months during winter, potatoes will germinate with more or less promptness after being planted in fairly moist soil. The usual planting season here is from the middle of January to the middle of February. Tubers planted during January send up sprouts nearly as rapidly as those planted later, but the young plants are apt to be injured by frosts. Potatoes planted December 23, 1899, and January 17, 1900, came up during February and were slightly injured by frost that occurred February 24, when the mercury fell to 26° at the ground, 29° in the government shelter, and 37° at the Weather Bureau, no injurious frosts occurring during March of that year. Potatoes planted January 9 and February 1, 1901, were slightly injured March 13, when the minimum temperatures were 27 at the ground, 32° in the government shelter, and 37 at the Weather Bureau. They continued growing until March 25, when those planted in January had reached a height of six to eight inches and those planted February 1, a height of two to four inches. Upon Relation of Weather to Crops 93 the above date the larger ones were nearly all killed to the ground, and the smaller ones considerably injured, the mercury falling to 26° at the ground, 30° in the government shelter, and 35° at the Weather B ureau. Potatoes that were planted February 22, and were just coming up, were very slightly injured. During five years' observations potatoes planted during Febru- ary have received no serious injury from frost, although some plants have been slightly injured each year. During April, potatoes that started in February or early March grow rapidly and early varieties begin forming tubers. Thrifty growth continues throughout most of May, if no unusually warm weather occurs. In 1902 an unsea- sonably warm period occurred between May 6 and 10, the maximum temperatures being 108° to 110° at the soil each day, and 99° in the government shelter, and the mean relative humidity but 20. Pota- toes planted January 20 and February 4 that were blossoming were considerably injured, and the crop was much lighter that year than usual. vSome injury was also done May 12 and 13, 1903, when the maximum temperatures in the government shelter were 102° and 106°, respectively. The increasing heat and aridity of June hasten the maturity or death of all potato tops, regardless of when they were planted or what the variety may be. Only early varieties have sufficient time to come to maturity before being overcome by the heat. The varieties that are grown most successfully in the region are Early Rose, Triumph, and Burpee's Extra Early. These varieties usually mature about the middle of June, although a large share of the ■crop is often dug and marketed considerably earlier than this. On account of the weather, the tubers deteriorate rapidly after ripening, whether dug or left in the ground. For this reason, by July 4 all the crop of the season is ordinarily consumed, except a small amount that a few growers save as best they can for summer planting. From seed saved from the spring crop, a few potatoes are grown during autumn. They are planted during August or early Septem- ber, and as a precaution against decay, are not cut. The sprouts sent up are usually distinctly slender and the subsequent growth is of the same character. As the cooler weather of autumn comes, they grow somewhat more rapidly, and produce a small crop of tubers. They do not usually have time for full maturity before the frosts of late autumn. In 1899 they were partly killed December 2, when the ground minimum temperature was 26°, in the government shelter 32°, and at the weather Bureau 38°, and were entirely killed 94 Bulletin 78 December 10, the minimum temperatures being 22° at the ground, 29° in the government shelter, and 34° at the Weather Bureau. During 1903, they were killed December 4, when the minimum tem- peratures were respectively, 25°, 34°, and 40^^ at the above points. As the heat causes the keeping of potatoes through the summer to be very difficult, the saving of a portion of the spring crop for seed for planting the next winter is not attempted; and as the fall crop is both very light and insufficiently matured, none of it is ordinarily used for seed about Phoenix. Nearly all the seed used for winter planting comes from the Pacific coast. Attempts have been made at the farm to preserve seed from season to season, but without satisfactory results. Attempts have also been made to interest growers in neighboring mountain valleys to produce seed for the warmer valleys, but the local demand near the former is so great that these attempts have met with no better success. The impracticability of preserving seed for succeeding plantings inter- feres materially with experiments with this crop, and renders the planting of varieties not grown near the region expensive. PUMPKINS AND SQUASH There is very little difference between the squash and the pumpkin. Pumpkin is the name given to the golden-yellow, flat- tened, ribbed types of the same species to which the summer squash belongs. The stem of the pumpkin has no enlargement where it joins the fruit, but many types of squash have. The bush squashes do well in the southern districts planted in the spring after danger of killing frosts. To take the place of the Hubbard squash, which does not thrive in the warm districts, the Cashaw should be grown, June or July being the best time for planting. In cool sections the Hubbard squash can and should be grown to a greater extent, as there is good demand for it in our markets. Pike's Peak is a good squash of the Hubbard type. Squash can be grown as a farming crop. QUINCES Quinces succeed in all parts of the State when provided with sufficient water. They are never injured by the cold of winter and it is very rare that their blossoms are killed by spring frosts. They withstand admirably the heat of summer in the southern valleys provided they are headed low and so pruned as to provide shade Relation of Weather to Crops 95 for the trunk. Quinces are especially resistant to alkali, but are susceptible to codling moth to the same degree as pears and apples. Were a market available, such as a jelly factory, large areas of quinces might be grown at a good profit. While all varie- ties do well, those which have done especially well at the Station Farm are Champion, Orange, Smyrna, Rea's Mammoth, and Meech's Prolific. RADISHES Radishes are easily grown during our cool season. The plant will stand considerable frost. The red, turnip-shaped varieties grow quickly but do not stay in good condition as long as the long white radishes. If people "would accept white radishes they would find them of much better quality than the short, red kinds, and there is more quantity to them. White Icicle is probably the best quality of radish that grows. White Strausburg is another good long white variety, which stands the heat better than most radishes. Early scarlet Turnip is a good red variety. Winter radishes are grown and stored like turnips. RASPBERRIES Raspberries produce well only in the cool moimtain valleys. The red varieties are propagated by suckers, while the blacks are propagated by tip layers. When the canes get "snaky" the tips are inserted in moist soil, where they root by fall. With the red varieties it is a problem to keep the canes from becoming too numer- ous, and with both varieties the old canes should be removed after fruiting, since a cane bears only once. The loganberry, Vvhich resembles the raspberry and the black- berry, succeeds a little better in the warm parts of the State, but is not a good yielder. Cuthbert is the most popular red raspberry, and Gregg is the most popular black. RHUBARB Rhubarb is a perennial plant which survives our hot summers in the southern part of the State with great difficulty; but at the higher elevations, especialty in the northern sections, it thrives and makes an excellent spring vegetable. The culture of rhubarb is similar to that of asparagus. Either seeds or plants are set out 4 by 4 feet, in very rich soil, fertilized with generous amounts of stable manure. The first year or two is used to develop a good, strong, vigorous plant, which can stand having its leaves removed. There is little choice in the few varieties offered. 96 Bulletin 78 I SHADE AND ORNAMENTAL TREES EOR PLANTING IN ARIZONA Deciduous and evergreen trees listed below will succeed ordi- narily in those sections of the State which fall within the altitude limits given, the (X) indicating successful growth. These altitude limits are necessarily arbitrary and have been chosen for con- venience. A few of the tender evergreen species will be injured with extraordinary freezes at the uppermost limits named, and a few of the high mountaia evergreen species may be found to grow with cultivation at altitudes lower than those suggseted. For further information concerning resistance of our cultivated trees to frost and for detailed information relative to the cultivation of these trees, see Timely Hints for Farmers, Nos. 62, 68, 79, 83, and 91. DECIDUOUS SPECIES Altitude limits 160- 2500- 5000- 2500 ft. 5000 ft. 7000 ft. Tree of heaven {Ailanthus glandulosa) White mulberry [Morns alba) Russian mulberry {Morus alba tarlarica) Teas' weeping mulberry (Morus alba var.) Honey locust [Cleditscia triacanthos) Arizona walnut {Juglans major) Osage orange; Bois d'arc {Toxylon pomifera) Weeping willow (Salix babylonica) Arizona ash (Fraxinus attenuata) Umbrella tree (Melia azedarach) Valley cottonwood {Populus MacDougali) Arizona mesquite (Prosopis velutina) Soapberry; Wild China berry {Sapiudns Druninwndii) Plumose tamarisk (Tarnarix juniperina) Native box elder {Acer interior) Western hackberry (Celtis occideri talis) Arizona sycamore {Platantis Wrightii) Black locust {Robinia Pseudacacia) American elm ( Ulmns americana) English elm ( Ulmns campestris) Russian oleaster [Elaeagmis angustijolia var. ) Lombardy poplar {Populus nigra italica) Carolina poplar {Populus deltoidea) Western cottonwood {Populus occidentalis) White or silver poplar [Populus alba) Bolley's poplar {Populus alba var. Bolleyana) Black cottonwood {Populus acuminata) American persimmon {Diospyros virginiana) Kentucky coffee tree {Gymnocladiis dioica) Native canyon ash {Fraxinus velutina) X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Relation of Weather to Crops 97 EVERGREEN SPECIES Italian cypress {Cupressus sempervirens) Arizona cypress {Cupressus arizonica) Oriental arbor vitae {Thuja orientalis) Blue elderberry tree {Sambucus caerulea) Indian cedar {Cedrus deodara) Nut pine {Pinus edulis) Mexican nut pine {Pinus cemhroides) One-seeded juniper {Juniperus monosperma) Alligator-bark juniper {Juniperus pachyphlaea) Rocky Mountain cedar {Juniperus scopulorum) Western arbor vitae {Thuja occidentalis) Silver fir {Abies concolor) Cork bark fir {Abies arizonica) Douglas spruce {Pseudotsuga niucronata) Western yellow pine {Pinus scopulorum) Arizonayellow pine {Pinus arizonica) Colorado blue spruce {Picea pungens) Engelmann spruce {Picea Engelmanni) Australian beef wood {Casuarina Cunninghamiana) . Bitter or Seville orange {Citrus aurantium vulgaris) . Guadalupe cypress {Cupressus guadalupensis) Monterey cypress {Cupressus macrocarpa) Desert gum {Eucalyptus rudis) Red gum {Eucalyptus rostrata) Gray gum {Eucalyptus tereticornis) Red box {Eucalyptus polyanthema) Narrow leaf iron bark {Eucalyptus crebra) California fan palm {Neowashingtonia filijera) Common olive {Olea Europea) Bagote {Parkinsonia aculeata) Canary palm {Phoenix canariensis) Date palm {Phoenix dactylifera) Japanese loquat {Eriobotrys japonica) Carolina palmetto {Sabal palmetto) Ironwood {Olneya tesota) Blue palo verde{Cercidium Torreyana) Chinese windmill palm {Chamaerops excelsa) Pepper tree {Schinus molle) ■Australian bottle tree {Sterculia diverstfoha) Altitude limits 150- 2400 ft X X X 4.500 ft X X X X X X X X X' X X X X X X X X X X X X X X X X X X X X X X X 5000- 7000 ft . X X X X X X X X X X X X X X X SHALLU (Sec tinder Grain Sorglmms) SORGHUM Sown at any time from April to the end of July, Club-head and Amber sorghums usually give a heavy yield of fodder. The sac- 98 Bulletin 78 charine sorghurrfs, also, vrhen planted in rows and cultivated pro- duce a fair quality of syrup. Forage sorghums are quite easily cured in this climate, but are often fed as they stand in the field. The season during which their seed will germinate begins during March, and continues until November. Seed does not germinate promptly but the young plants grow thriftily until April of most years. Little is gained by planting before the daily maximum temperatures rise to 85° or 90° F., and the minimum temperatures are over 45"^. They are uninjured by the warmest summer weather, when they ordinarily make their best growth. They are all killed when the mercury falls below 30° F., this usually occurring during November. A good crop may be secured ordinarily by planting any time from April to July. If the moisture supply is sufficient under dry farming, the earlier planting is best; if it is not present sufficiently to bring the crops up, the later planting is to be recom- mended, for the summer rains usually begin then and will carry the crop to maturity. SPINACH Spinach is the most popular plant grown for greens. It grows with ease during the cool season if given enough water and a rich soil. Mr. James Phillips, a market gardener at Globe, reports that the best way to grow spinach under irrigation is to sow it broad- cast in level borders and irrigate by flooding. The crowding causes the plants to grow upright, which makes bunching much easier. The soil must be very rich and free from weeds if this method is successful. Prickly, Winter and Bloomsdale are the popular varieties. SQUASHES Squashes can be grown quite readily in Arizona if suitable varieties are used and they are planted at the right time of the year. Squashes are less sensitive to cold than melons and will germinate earlier in the spring. The bush varieties will start during February, and the remaining varieties will start nearty as early. As soon as the frosts that usually occur in JNIarch cease, growth becomes more rapid and continues until the hot weather of June. The bush varieties come to maturity at this time and cease producing squashes. The running varieties continue growing some longer, but growth iS seriously interfered with if not stopped entirely, by the heat of mid- summer. The bush varieties have ample time to produce a fairly Relation of Weather to Crops 99 heavy crop, but few of the standard running kinds produce suffi- ciently well to justify their culture. These running varieties do best if planted during June or early July. The plants start well during the weather of these months, continue growing through summer, and produce a crop during autumn. The bush varieties will start during July and August and produce squashes during autumn, but do not grow as thriftily as during spring. STRAWBERRIES The strawberry is native to many of the high mountain regions of Arizona. While improved varieties may be grown in such locali- ties with comparative ease, their culture becomes more and more difficult with decrease in altitude, and in the hot dry valleys in the southern part of the State it requires considerable skill to manage the crop successfully. Consequently those who have this skill usually secure a high percentage of profit from strawberry culture, due to the very high prices obtainable. The greatest difficulty is carrying the newly set plants through the first summer. After becoming thoroughly established they do fairly well. The first good crop that can be counted on if the plants survive the first summer is during the spring of the second year after planting. Like alfalfa, strawberries, being perennials, are exposed to the climatic conditions throughout the year. Unlike alfalfa, however, they are very shallow-rooted, resembling in this respect the peren- nial grasses. Strawberries are less sensitive to cold than alfalfa, but are more sensitive to heat, resembling in this respect also the peren- nial grasses. The vegetative parts of none of the varieties of straw- berries are entirely killed by any low temperatures that occur in the region, and some of them produce some fruit throughout the coldest weather. On the other hand, all varieties are more or less injured by the heat of summer, only a few varieties withstanding the summer conditions, and a large percentage of- the varieties suc- cumbing entirely to the heat of midsummer. The varieties that have been experimented with most exten- sively and which seem the most promising ones for the region, are Arizona Everbearing, Michel's Early, Excelsior, Texas, and Lady Thompson.- The first variety mentioned has been grown in the region for many years, and is claimed to have originated near Phoenix. The second variety named has been grown here nearly as long, and is now more extensively planted than any other. The 100 Bulletin 78 last three named are newer varieties, and have been tested only a few years in the valley, mostly at the Station Farm. The period during which strawberry plants will grow if trans- planted extends from the latter part of October to the first of April, the month of February being the one during which they are trans- planted with the best success. During the fall months, while it is possi- ble to get most varieties to make a start, in many cases they die during the latter part of fall or early winter. If transplanted during the cold weather of December and early January, while they will not start to grow for some time, the most of them will eventually make a good growth. Those set during the latter part of January and during February usually start to grow promptly, and their growth is continuous until the hottest weather of summer. Those set after February start to grow promptly, but usually do not get sufficiently established before the hot weather of summer. Of the varieties mentioned, Michel's Early makes the poorest growth if transplanted during the fall, and Excelsior usually the best. Texas and Ever- bearing also make a fairly satisfactory start if transplanted during the fall. Michel's Early, set November 2, 1901, and supplied with plenty of water, died within two weeks, and most of those set December 6 of the same year died within a month. Michel's Early set November 24, 1902, made a much better start and grew fairly well the next spring. Plants of this variety set November 6, 1903, made a very poor start and have not since grown satisfactorily, while plants set December 2 became better established. Arizona Everbearing, set March 12, 1900, started well, and grew continuously until the hot weather of summer. Those not mulched with straw all succumbed to the heat, while three-fourths of those mulched with straw survived. Those set February 16, 1901, grew well until the hot weather of summer, but few plants survived the trying conditions of July and August. Plants of this variety set October 27, 1901, did not make a good start; those set November 24 of that year started better, but a large percentage died before the end of winter. Those set February 12, 1902, started well and grew continuously until injured by the heat of August, only a small percentage surviving the summer. Excelsior plants set December 2, 1901, started well, grew through most of the winter, and made excellent growth until the hottest M^eather of the following summer, when a large percentage of them succumbed to the heat. Only a small percentage of the plants of this variety set October 27, 1902, made a good start, and some of Relation of Weather to Crops 101 those set November 24 of that year failed to start. Those that became estabHshed lived through the winter, grew well the following spring, and survived the heat of summer well. Excelsior plants set February 15, 1903, started promptly, grew vigorously throughout the spring, few of them dying until the early part of August. During this month about 75 per cent of them succumbed to the heat. Plants of this variety set upon several dates during October of the season of 1903, started quite well and made a fairly good growth during the fall. Plants set November 6 and December 1 started and became quite well established. Lady Thompson plants set December 2, 1901, started fairly well, but did not become established and survive the winter well. The majority of the plants of this variety set October 27, 1902, failed to start, but the majority of those set November 27 of that year became well established, made a good growth the following spring, and survived the following summer quite well. Only a small percentage of Texas plants set October 27, 1902, started and became estabHshed, but nearly all those set November 24 of that year became well estabHshed, made good growth the following spring, and survived well the heat of the summer of 1903. Plants of this variety set February 16, 1903, started weH, became well estabHshed, and made exceHent growth until the hot weather of August. During the latter month a few of them succumbed to the heat, but most of them resumed growth when the cooler weather of September came. The plants of the dififerent varieties mentioned produce fruit at quite different times of the year in this region. The fruiting period of the Arizona Everbearing is usually during April, May, and June. While a few berries may be produced later in the summer than mentioned, and a few are sometimes produced during autumn, the amount is not sufficiently large to be marketed. The fruiting period of the Michel is of about the same length, but begins some earlier in the spring, extending from about the middle of March to the first of June. The Excelsior begins blooming during Oct ober ripens some fruit early in November, produces a considerable quantity by the end of November, and, if the weather is not too cold, produces a fair crop during December. Some fruit continues to ripen throughout the cpldest weather of winter, during March begins ripening in greater abundance, and continues to ripen through- out spring until about the first of June. The Texas behaves simi- larlv in this climate. It does not produce as much fruit during the winter but produces more during spring, the season during which 102 Bulletin 78 it produces most abundantly extending from the first of April to the first of June. The fruiting season of the Lady Thompson is a little earlier than the Everbearing and not quite so early as that of Michel or Excelsior, being much the same as that of Texas. The blossoms are injured by temperatures below 30° at the ground, but the young fruit endures temperatures as low as 24°at the ground and 28° in the government shelter without injury; and green fruit protected by the fohage endures temperatures sev- eral degrees below this. The ripening fruit endures less cold, being injured by temperatures below 25° at the ground. A good picking was taken from Excelsior plants December 24, 1903, although the mercury had fallen at the ground to from 22°to 26°dur- ing ten nights of the month. Some green fruits well protected with fohage survived January, 1904, the mercury falling to 14° at the ground one night, 16° one night, 17° two nights, 18° one night, and 19° three nights; and a few berries ripened during the early part of the month. SUDAN GRASS Sudan grass belongs to the nonsaccharine sorghums and is well adapted to Arizona conditions. It is very resistant to drought and makes a very valuable forage crop for dry-farming. It responds to moisture and can be groVn luxuriantly in the irrigated valleys of the State. Sudan grass is closely related to Johnson grass. In fact, it is difficult to distinguish one from the other without examining the root system. Sudan has no underground stems and is an annual. It will not become a weed pest as Johnson grass does in the irrigated sections. Sudan grass seed should be sown in the spring, as early as frost will allow. Under dry farming, if the moisture is insufficient for spring planting, planting should be done in July after the summer rains begin. Sudan can be planted in rows and cultivated like other grain sorghums, or sown broadcast. When planted in rows, under dry farming, seeding should be at the rate of 4 to 6 pounds per acre. Broadcasted or drilled seed under irrigation should be at the rate of 16 to 25 pounds per acre. It is best to plant in rows under dry- farming conditions. Sudan grass is limited in its growth by cold weather. Hot weather is favorable to its best development. SWEET CLOVER Sweet clover can be grown in all parts of the State, but will be a better economic crop for the dry-farming districts. Where irrigation water is abundant alfalfa will prove far more profitable. Relation of Weather to Crops 103 The variety best adapted to forage production is the yellow- sweet clover. This is a biennial and should not be confused with the annual, Melilotus indica, a common variety growing in many parts of the State as a weed pest under the name of "sour clover." Sweet clover should be sown in October or November on a well prepared seed bed. It may be sown, like alfalfa, from September to May. The best results, howcA^er, will be obtained by the fall sowing. Especially is this true in the dry-farming sections, where moisture conditions are more favorable at that time. Sweet clover, being a biennial, can be cut for hay the first season, and harvested for the seed crop the second, after which it dies. Sweet clover should be cut higher than alfalfa, as the new g rowth comes from the axils of the lower branches, and not from a surface crown. SWEET POTATOES Sweet potatoes may be grown in southern Arizona at altitudes of less than 4500 feet, where water is available. They should be started in a hotbed in February, and the slips transplanted to the field as soon as danger of frost is over. Sweet potatoes do best in well fertilized sandy soils, and should be frequently irrigated. They require a long growing season and the yield steadily increases until frost. No serious pests have been observed, and experience has shown the crop to be sure and profitable. The Large White and the Georgia Yam are juicy sweet varieties producing heavily. The White Vinelefes is an excellent market variety. Yellow Jersey, South- ern Queen, Shanghai, and Nansemond have also produced satis- factorily. TOBACCO This crop has not been tested thoroughly at the Station Farm, or elsewhere in the region, but the indications are that it may be grown successfully. A fair crop was secured the one season it was tested, and a fairly good product obtained. It can only be grown where irrigation is ample. The seed should be sown early in a good cold frame where the little plants maybe tended carefully. As soon as all danger of frost is past the plants may be transplanted to the field. TOMATOES Like potatoes, tomatoes are sensitive to both heat and cold' though not quite as sensitive to either. Tomatoes differ from pota- 104 Bulletin 78 toes in living through the summer and producing two crops on the same vines instead of requiring replanting. Tomatoes are propagated in two ways in this region: (1) By- planting the seed in the usual way in protected seed-boxes and either transplanting directly from these to the field or first transplanting to other boxes or to pots, and (2) by planting the seed in hills where the plants are to remain. As the latter method is the one that has proven preferable at the Farm, and as it is in following this method only that the seed and plants are exposed to outdoor con- ditions from the first, it is the one that will be discussed most fully. The principal advantages of planting the seed in hills outdoors are that this method involves less labor, and usually results in the pro- duction of an earlier and heavier crop. Though the seed may be sown much earlier in protected seed-boxes than outdoors, the trans- planting of the plants under our climatic conditions usually so checks their growth and renders them susceptible to disease that they are surpassed in growth and production by those planted in the field. Tomato seed will germinate outdoors and the young plants start and make continuous growth during most years from the middle of Februarv to the first of May. In 1899, seed planted in January did not send up many plants until the end of February, but they grew continuously thereafter, tomatoes maturing earlier than on plants grown from seed planted in boxes January 3 and transplanted April 10. vSome seasons the young plants receive some injury from frosts, l3ut as a rule few young plants are killed, enduring a surprising amount of cold if planted in the field. During the spring of 1900 the young plants from seed planted out February 10 were not injured by cold. In 1901, about a fourth of the young plants from seed planted Februar)- 14 were killed March 25, the minimum tem- perature being 26° at the ground, 30° in the government shelter, and 35° at the Weather Bureau. They had been uninjured by a previous frost March 13 when the minimum temperatures were 27° at the ground, 32° in the government shelter, and 37° at the Weather Bureau. In the spring of 1902, tomatoes growing from seed that had lain in the ground over winter were uninjured March 4, when the minimum temperatures were, respectively, 27°, 33°, and 38° at the above points; but were slightly injured March 26 when the minimum temperatures were 30°, 33°, and 36°, respectively, at the same points. During the spring of 1903 tomatoes were uninjured outdoors, though March 19 the mercury fell to 27° at the ground, 13° in the government shelter, and 36° at the Weather Bureau. Relation of Weather to Crops 105 After the early part of April the weather is sufficiently warm for tomatoes to begin making more rapid growth, and until the first of June most varieties grow with increasing rapidity. As the weather grows warmer, only the varieties with heavy foliage con- tinue thrifty. All varieties with finely divided or thin foliage are seriously injured by heat during June, and none of them produce much fruit. Only the Dwarf Champion, and a few related varieties with heavy foliage, can be counted on to produce a crop regularly. Fruit begins ripening during the latter part of June and increases in quantity until the middle of July. The vines continue to make some growth and to ripen fruit until about the middle of August. While they continue blossoming some through the summer, no fruit is ordinarily set after the middle part of July. Hence,, none ordinarily ripens during the latter part of August, or during Sep- tember. As the weather becomes cooler during the latter month, fruit again begins to set. It begins ripening during the latter part of October, the total amount of the crop depending upon the earli- ness of the fall frosts. The vines are usually killed during the latter part of November or the early part of December. In 1899, they were killed December 10, and in 1900 not until December 27. In 1901 they were slightly injured December 8, when the minimum temperatures were 27° at the ground, 81° in the government shelter, and 36° at the Weather Bureau, and were nearly killed the next morning, when the minimum temperatures were, respectivelyt 25°, 28°, and 33° at these points. In 1902, they were slightly injured November 16, when the minimum temperatures were 31° at the ground, 35° in the government shelter, and 43° at the Weather Bureau, were considerably injured November 26, when the minmium temperatures were, respectively, 29°, 32°, and 34° at these points; were partially killed November 28, when the minimum temperatures were 27°, 30°, and 34°; and were killed December 3, when the mer- cury fell to 24°, 28°, and 33° at the above points. During 1903 they were killed December 5, when the record showed minimum tem- peratures of 25° at the ground, 30° in the government shelter, and ?5^ at the Weather Bureau.' By comparing the records of spring and fall frosts it will be seen that young tomato plants endure quite as low temperatures as mature ones, and in some cases were uninjured by lower tem- peratures than seriously injured full-grown vines. In the fall, fresh growth is usually injured less than older growth, indicating that more vigorous action on the part of the plant renders it less suscepti- ble to the effects of frost. 106 Bulletin 78 Tomato Insects and Diseases. — The most serious disease which affects the tomato in this country is a wilt which may attack the plant in almost any stage. The sapwood of the plant is clogged near the ground, this being indicated by a tan colored area in the sapwood. The plant shows slight indications of disease until it wilts and dies. Little is known of this disease. Transplanted plants seem to be affected more than plants grown in place. The late- planted plants seem to be attacked less than early planted ones. Rotation may do some good, but there is no remedy known. Blight may attack the vines. This can be controlled by spraying the vines with Bordeaux mixture, made at the rate of 4 pounds of bluestone, 4 pounds of lime, and 50 gallons of water. This is a preventive, and not a cure for diseased vines. Blossom end rot seems to be caused by an irregular water supply, but this is not proven. Few insects trouble tomatoes. Cut worms may kill a good many young plants, but poison bran mash will control these. The "tomato worm," which attacks corn and cotton is widely distrib- uted and may do damage. There is no satisfactory remedy. TURNIPS Turnips of all varieties are easily grown in almost any part of Arizona. In the mountains they are grown in the summer and in the hot southern valleys in the fall, winter and spring. The seed will germinate in the southern valleys at any time from August to the succeeding May, in most cases germinating quickly during the warmest weather of this period and slowly during the coolest. During both the warmest and the coldest weather also, the young plants are apt to be injured, though injury by cold is less frequent and less severe than injury by heat. Well established plants are not severely injured by cold. All varieties do very well, including the rutabagas, which require a lower temperature for germination than turnips. VELVET BEANS Velvet beans, which are reported to grow so luxuriantly and to be so valuable as a forage and. green-manuring crop in some portions of the South, have not thus far proved valuable for this region, the aridity of the atmosphere probably being too great tor their suc- cessful culture. Relation of Weather to Crops 107 WALNUTS The Arizona walnut (yMg/aw5 wa/or), native in canyons and river valleys in parts of Arizona, is grown tD some extent as a shade and ornamental tree. It appears one of the hardiest and best adapted of all our deciduous trees. The Persian, or so-called English walnut, which is grown quite extensively in parts of California, succeeds well in valley soils in Arizona with abundant irrigation, when grafted on the native walnut stock. On its own roots, however, and usual- ly on the roots of the California black walnut, the English walnut has not been a success. There is a number of fine large English walnut trees grafted on Arizona walnut stock in the Upper Gila Valley, some of which have borne regularly for 15 years or more. A few thrifty English walnut trees also are growing about Tucson. Mr. C. R. Biederman's work in grafting and growing French, German, and English walnuts has so much of promise for the future of the walnut industry in the Southwest that the Experiment Station was led to issue Bulletin No. 76, "Walnut Growing in Arizona." This describes in full Mr. Biederman's methods of graft- ing and discusses the possibilities of commercial walnut growing in Arizona. By virtue of their late blooming habits and dense foliage, French walnuts appear best adapted to our climatic con- ditions. Some of the more promising of these are the Franquette and the Marquette. WATERMELONS Watermelons of prime quality are easily grown at the lower altitudes and in the valleys throughout central and southern Ari- zona. The period during which melon seed germinates extends from March (the time in the month depending on the season) until October. Most of the early varieties germinate earlier in March than the later ones, the Augusta starting the earliest of any tested at the Farm, but no varieties make much growth until the mercury ceases to fall below freezing at the ground. Seed planted before the latter part of March germinates very slowly and during the early stages the young plants are sometimes injured by frost and usually show little promise of giving better results than those planted later; but the first planted are ordinarily the first to produce ripe melons. Those planted during the early part of April ordinarily grow without interruption by cold, but usually ripen their melons a week or so later than those planted in March. During the warm weather of May and June, while the maximum 108 Bulletin 78 temperatures range from 90° to 105°, growth is rapid, the first melons ripening usually at the P^arm during the last week of the latter month, but occasionally as early as June 20. If the vines are supplied with sufficient water, the melons pro- duced are of prime quality until about the last of Jul}^ but from then on are apt to deteriorate, the early varieties first, and the later varieties later. By the middle of August the intense heat causes such early varieties as Augusta to be unfit for market, and a little later the Florida Favorite becomes affected by the heat. During the warm weather of August only the latest varieties or late- planted earlier \ arieties produce melons of good quality. If sup- plied with plenty of water the vines continue growth throughout the summ.er, and will produce melons of good quality during Sep- tember and October, especially if they are cut back and the soil between the rows cultivated and refurrowed. As seed germinates promptly, and young plants grow thriftily throughout the sum.mer, plantings for the production of fall melons may be made during June and early July. The vines from seed planted at this time grow rapidly through August and vSeptember, producing ripe melons in abundance during the latter month. As the cooler weather of October comes, growth and ripening are very slow, and during November or the early part of December the vines are killed by frosts. In 1899 they were killed December 1, the minimum temperatures at the ground being 28°, in the gov- ernment shelter 32°, and on the building of the Phoenix Weather Bureau, 39°. In 1900, with the occurrence of the above temper- atures October 28, they were only partially killed, not being en- tirely killed until December 3, when the mercury fell to 28° at the ground, to 32° in the government shelter, and to 35° at the Weather Bureau. In 1901, they were not injured by frost until December 8 and 9, the mercury falling to 25° at the ground upon the latter date. In 1902, they were killed November 26 and 27, the minimum temperature the latter night being 27° at the ground. In 1903, they were not killed until December 4, the minimum temperature being 25° at the ground, 34° in the government shelter, and 40° at the Weather Bureau This last record furnishes an illustration of the fact that plants may be injured or killed when the thermometer in the government Jihrlter, 5 feet from the ground, does not register a freezing temperature, and when the minimum temperature re- corded at the Weatbier Bureau is many degrees above freezing. The varieties h^f-> adapted to the southern valleys, as deter- mined by extensive tests at the Station Farm are Augusta, Florida Relation of Weathejr to Crops 109 Favorite, Sweetheart, Rattlesnake, Fordhook First, Blue Gem, and Kleckley Sweets. The Chilean is an excellent late variety. WHEAT {See under Grains) " RECAPITULATION From the foregoing discussion of the leading crops of the region and the effects of the weather on them, it will be seen that a larger number endure the low^ temperatures that occur than endure well the high ones, a condition the opposite of that existing in the north- ern portion of the country. Instead of crops being grown between two winters, as is the case in the North, the most of them are grown between two summers, the number that grow through the summer here being about the same as live through the winter in the North. Wheat, barley, oats, rye, peas, flax, canaigre, beets, alfalfa, clovers, lupins, vetches, cabbage, cauliflower, lettuce, spinach, carrots, turnips, radishes, onions, strawberries, olives, dates, oranges, lemons, pomelos, tangerines, loquats, and Eucalypts remain green throughout the winter, and make more or less growth. Of these the small grains, flax, canaigre, beets, clovers, cabbage, cauliflower, lettuce, spinach, carrots, turnips, radishes, onions, olives, and some species of Eucalypts are injured by the lower temperatures of winter. Besides those that grow through winter, beans, Indian corn, potatoes, and bush squashes grow only between the coolest weather of winter and the hot weather of summer, these being, like those Hsted above, sensitive to heat, but also sensitive to extreme cold. The crops keeping green through summer are the grain and forage sorghums, millet, cowpeas, peanuts, broom-corn, tobacco, cotton, alfalfa, tomatoes, melons, pumpkins, squashes, some varieties of beans, celery, strawberries, mulberries, persimmons, grapes, figs, plums, nectarines, peaches, apricots, almonds, apples, pears, quinces, walnuts, olives, dates, oranges, lemons, pomelos, pomegranates, loquats, cottonwoods, ashes, and Eucalypts. Of the above, the following grow thriftily throughout the hot weather of midsummer: Grain and forage sorghums, cowpeas, tobacco, cotton, olives, dates, and some species of Eucalypts. Of these the date is the one th^t seems to enjoy the summer condi- tions best. The crops liable to be injured by spring frosts are corn, potatoes, tomatoes, beans, grapes, peaches, apricots, almonds. The crops that 110 Bulletin 78 are usually injured by autumn frosts are corn, sorghums, beans, cow- peas, cotton, potatoes, and tomatoes. Those liable to injury by the low temperatures of winter are peas, alfalfa, lettuce, strawberries, dates, oranges, lemons, pomelos, and Eucalypts. The crops that are killejd or brought to maturity by the heat of summer are small grains, clovers, Indian corn, flax, bush beans, potatoes, summer squashes, cabbage, cauliflower, lettuce, spinach turnips, radishes, onions, rhubarb, raspberries, currants, and goose berries. In addition to the above the following are checked in their growth by the summer heat: Beets, alfalfa, tomatoes, melons, cucumbers, squashes, pumpkins, asparagus, strawberries, black- berries, deciduous fruits, citrus fruits, and Eucalypts. WHAT MAY BE PLANTED AND WHAT MATURES EACH MONTH Believing that information as to what may be planted each month with hope of success and what commonly matures each month in the Salt River Valley, will be of value, especially to new settlers, the following classified statement is inserted. In parts of southern Arizona having a cooler climate, planting is done later in the spring and earlier in the summer; and in the vicinity of the Colorado, planting takes place earlier in the winter and somewhat later in summer. In the first paragraph under each month is given the list of the crops that may be planted, and in the second paragraph those that mature or reach a stage suitable for use. It will be seen from what follows that the time for planting the largest number of drops is during January, February, and Sep- tember, and that the greatest number of crops mature during May, June, October, and November. During May and December com- paratively few crops are planted, and January and February are the months during which comparatively few crops mature. January Planted: Wheat, barley, oats, alfalfa, peas, beets, potatoes, cabbage plants, carrots, lettuce, spinach, turnips, radishes, aspar- agus seed and roots, onion sets, strawberries, blackberries, grape cuttings and plants, deciduous fruit trees, date seed. Mature: Cauliflower, lettucei, spinach, table beets, turnips, radishes, oranges, and pomelos. FEBRUARY Planted: Wheat, barley, alfalfa, Indian corn, peas, beets, to- bacco, potatoes, tomato seed, bush squashes, lettuce, spinach, tur- Relation of Weather to Crops 111 nips, radishes, onion sets, celery seed, asparagus plants, cabbage plants, strawberries, blackberries, deciduous fruit trees, citrus fruits, olives, date seed. Mature: Cauliflower, cabbage, lettuce, spinach, table beets, tur- nips, radishes. MARCH Planted: Indian corn, grass seed, cotton, beans, peanuts, melons, cucumbers, squashes, pumpkins, citrus fruits, olives, Eucalypts. Mature: Cauliflower, cabbage, lettuce, spinach, beets, turnips radishes, carrots, green onions, asparagus, strawberries. APRIL Planted: Grain sorghums and broom corn, grass seeds, cowpeas, peanuts, cotton, date plants, Eucalypts. Mature: Grain hay, alfalfa, green peas, cabbage, lettuce, spinach, table beets, carrots, turnips, radishes, green onions, asparagus, strawberries, mulberries. MAY Planted: Grain sorghums and broom corn, cowpeas, date plants. Mature: Wheat, barley, oats, alfalfa, table corn, peas, potatoes, bush squashes, string beans, cabbage, lettuce, table beets, carrots, turnips, asparagus, strawberries, blackberries, plums, apricots, peaches. JUNE Planted: Grain sorghums and broom corn, cowpeas, melons, squashes, pumpkins, date plants. Mature: Alfalfa, Indian corn, potatoes, tomatoes, melons, cu- cumbers, bush squashes, beans, beets, carrots, onions, strawberries, blackberries, figs, plums, peaches, apricots, apples. JULY Planted: Indian corn and grain sorghums, millet, cowpeas, mel- ons, squashes, pumpkins, date plants. Mature: Cowpeas, sugar beets, alfalfa, tomatoes, melons, cu- cumbers, grapes, figs, plums, peaches, apples, pears. AUGUST Planted: Peas, beets, beans, cowpeas, millet, potatoes, cabbage and cauliflower seed, carrots, celery plants, cucumbers, lettuce Eucalypts. 112 Bulletin 78 Mature: Grain and forage sorghums, sugar beets, cowpeas, to- matoes, melons, grapes, figs, plums, peaches, apples, pears, almonds. SEPTEMBER Planted: Wheat, barley, oats, grass seeds, peas, beans, potatoes, beets, cabbage and cauliflower seed and plants, celery plants, let- tuce, spinach, radishes, beets, carrots, turnips, onion seed. Mature: Grain and forage sorghums and broom corn, cowpeas, peanuts, cotton, melons, grapes, plums, peaches, apples, pears, dates, pomegranates. OCTOBER Planted: Small grains, grass seeds, alfalfa, clovers, peas, beets, cabbage seed and plants, cauliflower plants, onion seed, carrots, radishes, turnips, lettuce, spinach. Mature: Cowpeas, cotton, grain and forage sorghums and broom corn, millet, alfalfa, tomatoes, melons, cucumbers, squashes, pumpkins, string beans, peanutfe, grapes, plums, peaches, apples, quinces, pears, dates, pomegranates. NOVEMBER Planted: Small grains, alfalfa, clovers, peas, cabbage plants, rad- ishes, beets, turnips, lettuce, spinac'h, strawberries, date seed. Mature: Grain and forage sorghums, cowpeas, alfalfa, potatoes, tomiatoes, pumpkins, squashes, peas, beans, lettuce, spinach, table, beets, turnips, radishes, celery, strawberries, grapes, peaches, apples, pears, quinces, olives, dates, oranges, pomelos, pomegranates. DECEMBER Planted: Small grains, peas, radishes, strawberries, date seed. Mature: Lettuce, spinach, table beets, turnips, radishes, celery, strawberries, apples, pears, olives, dates, oranges, pomelos. WHEN EACH CROP MAY BE PLANTED AND WHEN IT MATURES For the further convenience of those desiring information con- cerning the planting of crops, the proper time for planting each and the time when each usually matures in the vicinity of Phoenix, are given. Our seasons are so different from those in most portions Relation of Weather to Crops 113 of the country that those unfamiliar with the region are naturally apt to become somewhat confused as to the proper time for planting the great variety of crops that can be grown in the region. The times given are those when experience has shown that each crop should be planted in order to secure the best results. The time of maturity given is that when each crop reaches the stage when it is most suitable for the use for which it was planted. In the case of many vegetables this is while the plant is still in a green immature state; and in the case of such a fruit as pears it is some time after, not only the cessation of gtowth on the part of the tree, but of the removal of the fruit itself. ALFALFA Planted: September 20 to November 10; January and February. Mature: April 15 to August 15; October 15 to November 15. ALMONDS Planted: January and February. Mature: July and August. APPLES Planted: January and February. Mature: June 15 to December. APRICOTS Planted: January and February. Mature: May 10 to June 20. ASPARAGUS Planted: January to March; October and November. Mature: March and April of third year, and after. BARLEY Planted: September to March 1. Mature: April and May. BEANS Planted: March and first half of April; August 15 to Septem- ber 15. Mature: May 15 to June 15; October 20 to November 15. 114 Bulletin 78 beets, table Planted: January to March 15; September and October. Mature: January to July; October to December. BEETS, SUGAR Planted: January 15 to end of February; September 20 to Octo- ber 10. Mature: July and August; March. BLACKBERRIES Planted: January and February. Mature: May and June of second year. BROOM CORN Planted: April to July. Mature: September to November. CABBAGE Seed planted: August 15 to November. Plants set: January and February; September 15 to October 20. Mature: February to June. CARROTS Planted: January and February; August 20 to October 15. Mature: January to July; November and December. CAULIFLOWER Seed planted: August and September. Plants set: September and October. Mature: January to April. CELERY Seeds planted: January to March. Plants set: August 15 to October 15. Mature: November and December. CLOVER, "sour" Planted: October 15 to November 20. Mature: March. CORN, EGYPTIAN Planted: April 15 to July 15. Mature: September and October. Relation of Weather to Crops 115 corn, indian Planted: February 20 to March 15; July 10 to August 5. Mature: May 15 to June 15; October and November. CORN, KAFIR Planted: April, May, and June. Mattire: September and October. COTTON Planted: March and April. Mature: September to December. COWPEAS Planted: April to August. Mature: August to November. CUCUMBERS Planted: March and April; June and July. Mature: June and July; September and October. DATES Seed planted: All seasons. Plants set: April to August. Fruit Mature: September to January. EUCALYPTS Seed planted: August to January. Plants set: March, April, and August. FETERITA Planted: April to July. Mature: July to October. FIGS Planted: January and February. Mature: June and July. GRAPES Planted: January and February. Mature: July 10 to December. GRASSES Brome, blue, and orchard grasses. 116 Bulletin 78 Planted: September to May. Bermuda and Johnson gjasses. Planted: April to October. LETTUCE Planted: January, February, September, and October. Mature: January to May. MELONS Planted: March and June. Mature: June 20 to November. MILLET Planted: August. Mature: October. MILO MAIZE Planted: April to July. Mature: July to October. OATS Planted: October to December. Mature: April and May. OLIVES Planted: February and March. Mature: October to January. ONIONS Seed planted: September 15 to October 15. Sets planted: November to February. Green onions: February to April. Mature: June and July. ORANGES Planted: February and March. Mature: November to January. PEACHES Planted: January and February. Mature: May 25 to November. PEANUTS Planted: March. Mature: September and October. Relation of Weather to Crops 117 PEARS Planted: January and February. Mature: July to January. PEAS Planted: January and February; August 20 to November 20. Mature: April, May, and November. PLUMS Planted: January and February. Mature: May 10 to October. POMEGRANATES Planted: January and February. Mature: October and November. POMELOS Planted: February and March. Mature: November to January. POTATOES Planted: January 15 to February 15; and August 20 to Septem- ber 10. Mature: May 20 to June 15; November. PUMPKINS Planted: March and June. Mature: July and October. QUINCES Planted: January and February. Mature: October. RADISHES Planted: January to March; August to October. Mature: January to August; October to December. SHALLU Planted: April, May, June. Maitire. August to October. SORGHUM Planted: May and June. Mature: September to November. 118 Bulletin 78 SPINACH Planted: January, September, and October. Mature: November to May. SQUASHES Planted: March, June, and August. Mature: May, June, and October. STRAWBERRIES Planted: November 20 tp February 20. Mature: March to July; December. SWEET POTATOES Planted: March to May. Mature: September to November. TOMATOES Planted: February and March. Mature: June 20 to August, and October 20 to December. TURNIPS Planted: January, February, August, September, and October. Mature: October to May. WHEAT Planted: September to March. Mature: April to June. In using the above tables due allowance in time should be made for other parts of the State than Salt River Valley, to which they particularly apply. In the Colorado Valley, near sea level, for instance, limiting temperatures both of heat and frost are two to four weeks earlier in the spring and about two weeks later in the fall. At higher elevations limiting temperatures occur correspondingly later in the spring and earlier in the fall. University of Arizona Agricultural Experiment Station Bulletin No. 79 Plant of Opuntia /icw tnrfj'ca in the introduction garden, University Farm, badly injured with a temperature of 21 degrees F. The illustration shows 6 months growth since the freeze. Cold-Resistance in Spineless Cacti By J. C. Th. Uphof INTRODUCTION By J. J. Thornber Tucson, Arizona, December 1, 1916 University of Arizona Agricultural Experiment Station Bulletin No. 79 t.. Plant of Opunlia ^c«s tnrfica in the introduction t^rden, University Farm . badly injured with a temperatur eof 21 degrees F. The illustration shows 6 months growth since the freeze. Cold-Resistance in Spineless Cacti By J. C. Th. Uphof INTRODUCTION By J. J. Thornber Tucson, Arizona, December 1, 1916 UNIVERSITY OF ARIZONA AGRICULTURAL EXPERIMENT STATION GOVERNING BOARD (Regents of the University) Ex-Officio Hon. George W. P. Hunt, Governor of the Stats Hon. Charles O. Case, Supt. Pub. Instruction Appointed by the Governor of the State Frank H. Hereford, Chancellor William V. Whitmore, A. M., M. D., Treasurer William J. Bryan, Jr., A. B., Secretary Lewis D. Ricketts, Ph. D., Regent William Scarlett, A. B., B. D., Regent Roderick D. Kennedy, M. D., Regent Rudolph Rasmessen, Regent Frank J. Duffy, Regent RuFUS B. von KleinSmid, A. M., Sc. D., , President of the University AGRICULTURAL STAFF Robert H. Forbes, M. S., Ph. D., Director John J. Thornber, A. M., Botanist Albert E. Vinson, Ph. D., Biochemist Clifford N. Catlin, A. M., Assistant Chemist George E. P. -Smith, C. E., Irrigation Engineer Arthur L. Enger, C. E., Assistant Engineer George F. Freeman, B. S., , Plant Breedei Walker E. Bryan, M. S., . . . . . Assistant Plant Breeder Stephen B. Johnson, B. S., Assistant Horticulturist Richard H. Williams, Ph. D., Animal Husbandman Walter S. Cunningham, B. S., Assistant Animal Husbandman John F. Nicholson, M. S., Agronomist Herman C. Heard, B. S. Agr.. .... Assistant Agronomist Austin W. Morrill, Ph. D., . . . . Consulting Entomologist ^STES P. Taylor, B. S. Agr., Director Extension Service George W. Barnes, B. S. Agr., Livestock SpeciaHst, Extension Service L. S. Parke, E. S Boys and Girls State Club Agent Edith C. Salisbury, B. D. S Home Economics Specialist Arthur L. Paschall, B. S. Agr., . . County Agent, Cochise County Charles R. FillERUP, D. B., . County Agent, Navajo-Apache Counties Alando B. BallanTyne, B. S., County Agent, Graham -Greenlee Counnes John R. TowlES, Secretary, Extension Service Frances M. Wells, Secretary, Agricultural Experiment Station The Experiment Station offices and laboratories are located in the University buildings at Tucson. The new Experiment Station Farm is situated two miles west of Mesa, Aiizona. The date palm orchards are three miles, south of Tempe (cooperative, U. S. D. A.), and one mile southwest of Ymna, Arizona, respectively. The experimental dry-farms are near Cochise and Pres- cott, Arizona. Visitors are cordially invited, and correspondence receives careful attention. The Bulletins, Timely Hints, and Reports of this Station will be sent free to all who apply. Kindly notify us of errors or changes in address, and send in the names of your neighbors, especially recent arrivals, who may find our publications useful. ^ ^ „«.«,^., Address, THE EXPERIMENT STATION, Tucson, Ariiona. CONTENTS 1 1Q Introduction '■^^ Histological Studies 123 General structure of the outer, thickened part or integument of a cactus stem ^■'"^ Study of relative thickness of cuticle, crystal-bearing cell layer, and thick-walled cells of different spineless opuntias 126 Relation of penetration of temperature to thickness of integument of cacti 128 Physiological Studies 1^^ Effects of temperature at the melting point of ice on the tissues 130 Protoplasmic movements *-^'- Determination of cooling and freezing points in cacti 131 Comparison of cooling points, freezing points, and duration of freez- ing points in different spineless cacti 132 Summary of results of ten experiments with each of six species and varieties of Opuntia l*** Results of other workers • l^* Comparison of results 1^^ Effects of freezing the tissues 138 Effects of cold on the protoplasm 140 Table showing temperatures at which pieces of cactus stems were damaged and also killed outright, with differences in temperature.... 141 Behavior of plants of spineless cacti growing in the introduction gar- den at the University Farm, during the winter of 1915-1916 142 Summary 1*3 ILLUSTRATIONS PLATES Plate I. Plant of Opuntia Castillae in the cactus garden. University grounds, uninjured with a temperature of 12 degrees F., but seriously frozen with a temperature of 6 degrees F ..Frontispiece Plate II. Plant of Opuntia sp. Burbank Special in the introduction garden, University Farm, injured with temperatures of 20 degrees F. Plant of rather rapid growth Frontispiece FIGURES Fig. 1 .-Cross-section of a piece of joint of Opuntia castillae about two weeks old, showing regular character of cells 125 Fig. 2.-Cross-section of a piece of joint of Opuntia castillae about two years old 126 Fig. 3.- Cross-section of a piece of joint of Opuntia sp. Burbank Special about two years old 127 Fig. 4.-Cross-section of a piece of joint of Opuntia Ellisiana about two 3'ears old 127 Fig. 5.-Apparatus used for determining the rate of penetration of temper- ature through the integuments of various spineless cacti; and also for making a. comparative study of the cooling points, freez- ing points and duration of freezing points of difTerent spineless cacti 129 Fig^ 6.-Curve showing cooling point, freezing point and duratiori of freez- ing point of Opuntia castillae 132 Fig. 7.-Curve showing cooling point, freezing point and duration of freez- ing point of Opuntia Ellisiana , 133 Fig. 8.-Curve showing cooling point, freezing point and duration of freez- ing point of Opuntia sp. Burbank Special 133 Fig. 9.-Curves showing the freezing of dead tissues of spineless cacti, in- cluding Opuntia sp. Burbank Special, Opuntia fusicaulis, and 0. ficus indica 137 Fig. lO.-Apparatus used for studying the effects of low temperatures and of freezing on the protoplasm of cacti 139 Plate I. Plant of Ojnimid L dslilldf in tilt; cactus Karden, University groLuidb, uninjured with a temperature of 12 degrees F., but seriously frozen with a temperature of 6 de- grees F. Plate II, PlaTit of Onnnlia ^\) . Hiirbank Special in the iiiLroductioii garden, University Farm, injured with temperature of 2U degrees F. Plant of rather rapid growth. Cold Resistance in Spineless Cacti INTRODUCTION The differences in the frost resistance of cacti, the importance of these plants in parts of Arizona as emergency and supplemental stock feed, and the perennial interest in spineless cacti as possible forage plants, led to the outhning of this Adams fund project. This study has for its object the determination of the causes of hardi- ness in cacti and is designed to throw light on the question as to whether resistance to cold in these plants lies in the character and structure of the plant body or in the character of the cell sap and the protoplasm. An attempt has been made to determine the limits of resistance in several species and varieties of spineless cacti. These plants have been studied both in the field and in the laboratory with reference to the relation between their morphology and physi- ology and cold resistance. The behavior of their protoplasm at low temperatures has been carefully noted. No attempt has been made to determine the critical temperature which the plant can endure without injury to its tissues, but the minimum freezing tem- perature which has been found to damage the plant has been noted, also the temperature at which the plant is killed quickly. The results obtained in this study by Mr. Uphof check closely with field observations made by the writer on Opuntia castillae over a period of fifteen years. This experiment was also suggested partly through the failure of Burbank spineless cacti to grow successfully under Arizona con- ditions and to endure our winters, as noted by the writer in Bulletin 67 of this Station. This observation, together with the fact that our State has a rich and varied cactus flora, led to numerous speculations concerning the factors of hardiness in cacti. Though this study has been outlined for some time, the lal^oratory work was begun by Mr. Uphof, in cooperation with the writer, only last summer. Recent studies in the native cacti of our State have led to the observation that the various species almost invariably have a limited altitudinal distribution. This means, in brief, that the different species are confined to areas similar in temperature and rainfall conditions. In a few instances low winter temperatures are known to be the chief factor in limiting the distribution of certain species, as, for example, Cereus Thiirheri, the organ-pipe cactus, Cereus giganieus, the giant cactus, and Cereus Schottii. The explana- 120 Bulletin 79 tion underlying the distribution of the great number of our cacti, however, has not been made, although in the light of Mr. Uphof 's experiments minimum winter temperatures are a factor. In this connection it will be interesting to observe that during the very- cold winter of 1912-13 thousands of small giant cactus plants growing near their greatest altitudinal limits were killed outright. Many other species also suffered great damage. For this study in hardiness, plants of spineless cacti — spineless platopuntias — were secured from various sources, and, together with those already growing on the University grounds, were set in the introduction garden at the University Farm, in the spring of 1914. The writer is under obligation to Fraser Bros., Wellton, Arizona, for a number of varieties of spineless cacti, including Opuntia ficus indica, from Sicily and Malta, and Opuntia sp. Burbank Special. The latter was thought to be a very hardy variety. Mr. B. R. Russell, San Saba, Texas, kindly furnished plants of Opuntia Ellis- tana, which he calls the San Saba spineless pear. This latter species is entirely spineless and has shown itself hardier than any other variety of spineless cactus growing in the introduction garden. It is, however, slower growing than some other species. Other species represented were Opuntia fusicaulis, a slender jointed spineless pear, which the writer found in cultivation in Tucson gardens, and Opuntia castillae. These were recently described by Dr. Griffiths and are native to Mexico. Opuntia castillae is known to have been growing in Tucson in the gardens of various vSpanish and Mexican residents for as long as thirty years and is commonly known as "nopal de castilla." Forms of it are entirely spineless, though the younger joints have a few fine spicules which sooner or later disappear. It is often seen in cultivation in parts oi south- ern California, where it is occasionally used as a hedge plant. Under the most ordinary conditions it grows to a height of 6 to 10 feet, the trunks and older branches becoming quite stout with age. It is not injured by our highest summer temperatures, even with rather arid culture, though for good growth it should have a rea- sonable amount of soil moisture. It is well adapted for growing in southern Arizona, where the lowest winter temperatures do not fall below— 12.2° or —11.1° C.(10° or 12° F.). In December,1901, it was not injured with a tempeiature of —12.2° C. (10°F.), extending over a few hours. In January, 1913, it was frozen back one-half, or more, on the University grounds, and also in Tucson with a temperature of — 14.4° C. (6° F.). This latter temperature extended over a considerable portion of the night and was preceded by nearly Coi^d-Resistance in vSpineivEss Cacti 121 24 hours of almost continuous freezing weather. This is said to be the lowest temperature ever recorded for Tucson. At Phoenix, Arizona, this species was killed back about one-fourth to one-fifth during this same cold spell. The soil in the introduction garden is deep and alluvial in character. Ic is a fine, sandy loam and has good drainage. Some black alkali is present, though apparently this has not injured the growth of these cactus plants in the least. The cuttings were planted on low ridges and cultivated and irrigated between the rows, all the plants being given the same care. The soil has been kept in good condition during the growing season of the plants. The various plants have made at best but a moderate growth, par- ticularly when the favorable growing conditions are considered. Opuntia castillae, Opuntia ficus indica, Opuntia fusicaulis, and Opuntia sp. Burbank Special grew to heights of 14 to 24 inches during the first year with 4 to 8 joints each. Plants of Opuntia Ellis- iana made growths of 10 to 12 inches with 2 to 5 joints each. As already noted, this is a slower growing species than the others, but very hardy. The winter of 1914-15 was milder than usual and little damage from frost was done to the matured growth of any but the tenderest species, viz., Opuntia ficus indica, 0. fusicaulis, and Opuntia sp. Burbank Special. The lowest temperatures at the Uni- versity grounds for the winter season were — 4.4° C. (24° F.) on December 9, and —5.6° C. (22' F.) on the nights of December 15, 1914, and January 8, 1915, respectively. These temperatures were of short duration. Opuntia Ellisiana and 0. castillae were not injured in the least, while Opuntia fusicaulis, 0. ficus indica, and Opuntia sp. Burbank vSpecial were only slightly injured. The greatest injury was done by the freeze of December 8, since up to that time the weather had been mild, and some of the plants were making considerable growth. Naturally, the tender immature joints were easily killed. Altogether, the plants came through the winter season in good shape and began a healthy growth in the spring of 1915. It is interesting to observe that Opuntia castillae and 0. Ellisiana ceased their growth by the middle of October, or the first of Novem- ber at latest, even with favorable growing conditions. Opuntia ficus indica, 0. fusicaulis and Opuntia sp. Burbank Special, on the other hand, continued growth ordinarily until freezing weather began in December. There may be some relation between hardiness in Opuntia castillae and O Ellisiana and their better adaptability to our climatic conditions. This, however, might account for hardiness 122 Bulletin 79 in these plants only so far as the first severe cold spell is concerned. The immature joints of these species which continue growth until a severe freeze, are naturally killed with the first heavy frost. How- ever, the matured growth of Opuntia ficus indica and Opuntia sp. Burbank Special, which ceased their growth before freezing weather, showed no greater resistance to cold than the matured growth of plants that had made active growth until frost. In concluding this statement it should be said that the laboratory work has been done entirely by Mr. Uphof, who is a Hollander by birth and training, and has resided in this country for but a few years. While he took very careful notes on his experiments, it was not possible for him, without help, to write up his results for publication. This fell to the lot of the undersigned, who has en- deavored to state the results as Mr. Uphof understands them. Mr. Uphof has gone over this paper several times with the writer's help, and has made numerous suggestions to state more fully his ideas. With this brief statement, the writer asks that this work be regarded as Mr. Uphof's. J J Thornber. Cold-Resistance; in Spineless Cacti 123 HISTOLOGICAIv STUDIEvS GENERAL STRUCTURE OP THE OUTER, THICKENED PART OR INTEGUMENT OE A CACTUS STEM It is quite difficult to make thin hand sections of living cacti and similar succulent plants, as the tissue is soft and often slimy and does not section readily. It was found that sections could be made for ordinary study with a hand microtome. In order to study the tissues from a histological or cytological standpoint, however, it was necessary to embed small pieces of the cactus in paraffin and make sections with a rotary microtome. A histological study of certain parts of the cactus plant is- very essential, as it is one of the means which may determine- whether a certain species is hardy or not. The difference between: the outer tissue layers of different species of cacti, especially those which are resistant to certain low temperatures, and those which are not, is very remarkable. In order to show these differences, joints oi several species of Opuntia of different ages were selected. I first made a study of the layers of tissue outside the woody bundles of a well developed two-year-old joint of Opuntia castillae. In studying a section of this under the microscope, the thick-mem- braned cells at the periphery, or outside, and the large thin-walled cells toward the center of the stem, or joint, were observed. The first layer encountered is the epidermis; it can still be detected easily in stems which are three and even four years old. The epidermal cells of two-year-old stems sometimes contain protoplasm; however, this seems to be an exception in the plants which were worked with. The epidermis soon secretes a cuticle or secondary membrane, which after a few months becomes quite thick. When young this is stained light yellow with a concentrated solution of potassium hydroxid; older cuticles stain darker yellow, which sug- gests that the outside membrane of the epidermis is heavily satur- ated with suberin, the same substance which forms in cork. The stomata, or breathing pores, are small but numerous and are embedded in the cuticle. Immediately below the epidermis follows a layer which we will call the "crystal-bearing layer," since its cells always bear crystals. Its outer and lateral membranes are thin, but the ones toward the 124 Bulletin 79 center of the plant are thick. Its cells are characterized by the presence of crystals of calcium oxalate; when young these are star- shaped, but with age they lose their beautiful stellar appearance and come to occupy practically the entire space in the cell. Later crystallization of these bodies through lack of space is very irregular. The calcium oxalate everywhere lies closely next the inner membrane of the cell and forms, with similar material of the neighboring cells of the same layer, a continuous crystaUized wall under the epidermis. The next layer of tissue is usually three to five cells thick and with age has very thick membranes, which also are suberized, though not so heavily as the cuticle. This layer is everywhere furnished with plasmodesmi fi. e., connections of protoplasm between different cells through the cell walls,) which are rather difficult to detect but which are shown beautifully under the microscope when the sHdes are immersed for a few minutes in each of the following solutions, in the order named: 1. 1 per cent osmic acid. 2. Potassium iodid in iodine. 3. 25 per cent sulphuric acid. The sulphuric acid swells the membranes and shows the plas- modesmi clearly. The writer observed that tissues afterwards put for a moment in Delafield's haematoxyUn until the membranes become light red sometimes show good results. The tissue lying between the thick-celled layers, already described, and the woody part of the joint, is a large-celled parenchyma, or soft tissue. In comparison with the others its membranes are thin, and often show plasmodesmi, which can only be detected, however, with the already noted precautions. These cells are mucilaginous and contain several large chloroplasts or green bodies. Kach of these chloroplasts contains, during sunny days, from 4 to 12 small starch grains. The cells toward the central part of the joint contain fewer chloroplasts and less of the mucilaginous matter, but, on the other hand, more water. Some cells of this parenchyma show star- shaped crystals of calcium oxalate somewhat similar to those already noted. The origin of the different layers and cells of a stem, or joint, may be studied to best advantage in young joints. Here the epidermis appears as a tissue formed by the dermatogen,* while the cells of the crystal-bearing layer, the thick-celled layer, and adjacent large-celled parenchyma (all together forming the cortex) • Dermatogen and periblem belong to the primary tisiuea of a growing stem. Cold-Reststance in Spineless Cacti 125 lie, in an early stage, in a straight radial direction and take their ori- gin from the periblem, which direction may be observed here and there in Fig. 1. At a later age it is impossible to find out how the tissues were formed, as the cells of the green parenchyma sometimes divide longitudinally, and the thick- walled cells are so crowded that they no longer lie inradial rows. Fig. 1. — Cross-section of a piece of joint of Opuntia castillae about two weeks old, showing regular character of cells. (Highly magnified). It is hardly necessary to mention that the thick cuticle, the crystal-bearing layer, and its adherent thick-celled tissues, together with the slimy contents of the green parenchyma, are of great importance to the plant, as these protect the stem against a high transpiration rate, which would be disastrous for the species in a dry and hot climate. It would not be worth while to describe the thickness of the layers of that part which forms the integument of the stem (i. e., cuticle, epidermis, crystal-bearing layer, and thick- celled layer) if it were not observed that this integument is thickest in those species which are resistant to cold. More than this, physiological experiments demonstrated that the time of penetra- tion of a certain temperature varies greatly when integuments of different species of cacti are used. 126 BULLE^TIN 79 It will be interesting, therefore, to describe the outside layers of each of the six species of cacti with which the writer worked. STUDY OF RELATIVE THICKNESS OF CUTICLE, CRYSTAL-BEARING CELL LAYER AND THICK-WALLED CELLS OF DIFFERENT SPINELESS OPUN- TIAS 1. Opuntia castillae has a cuticle 15 to 20 \k thick, the cells of the crystal-bearing layer are from 30 to 42 [x thick, and the following thick-celled layer islOO to 120 [x thick. Individuals from the Uni- versity Farm, from the cactus garden on the campus of the University of Arizona, and from a garden in the vicinity of Tucson were obtained. These plants all showed the same general structure. In the writer's experiments, plants from the University Farm were used, as the other species which follow were also grown in the introduction gar- den at the University Farm under similar conditions. This species was damaged at a temperature of — 14° C. (6.8° F.). 2. 0. ficus indica, from Malta. This species shows, in compari- son with the former, a cuticle 5 to 10 [x thick; the crystal-bearing layer is 30 to 38 [jl thick, and the thick-celled layer is 55 to 75 {i,. in thickness. This species is not hardy in the field and was injured at temperatures below — 6° C. (21.2° F.) in the laboratory. Fig. 2. — Cross-section of a piece of joint of Opuntia casliUa* about two years old. The integument is thick. (Highly magnified) CoIvD-Resistance in Spineless Cacti 127 Fig. 3. — Cross-section of a piece of joint of Opunlia sp. Burbank Special, about two years old. Note the relatively thin integument. (Highly magnified). Fig. 4. — Cross-section of a piece of joint of Opun- tia Ellisiana about two years old. Note the thick integument. (Highly magnified). 3. Opuntia sp. Burbank Special. The integument of this species is thin. The cuticle is 5 to 8 ji. thick, the crystal-bearing layer 30 to 38 [K, and the thick-celled layer 70 to 87 [i. This species is not hardy and was killed at a temperature of — 8° C. (17.6° F.). 4. 0. Ellisiana has, Uke 0. castillae, a thick cuticle of 12 to 15 [x, a crystal-bearing layer of 25 to 35 [x, and the next layer of 75 to 130 [I. This species is quite hardy; it is said to be resistant to tern- 128 Bulletin 79 peratures of — 17'' C. (1.4° F.). No direct observations, however^ have been made in the field at this low temperature. 5. O.fusicaulis has a cuticle 10 to 12 (jl thick, a crystal-bearing layer of 20 to 30 tx, and a thick-celled layer 87 to 98[x.in thickness This species is not hardy. It is injured at a temperature of — 6° C. (21° F.). 6. O. ficus indica, from Sicily, has a cuticle 12 to 15 \i. thick, a crystal-bearing layer 30 to 40 [x, and a thick-celled layer 62 to 74tx.in depth This species is not hardy; it is injured at tem- peratures below —5° C. (23° F.). It will be observed that the cuticle and the thick-celled layer show great differences in thickness, while the crystal-bearing layer is more nearly of the same thickness throughout. The table below gives a summary of the thickness of the various layers noted above. ^ SUMMARY OF THICKNESS OF CELL LAYERS IN CACTi Name of plant Opuntia castillae O. sp. Burbank Special. . . . O. ficus indica, from Malta O. Ellisiana 0. fusicaulis O. ficus indica, from Sicily. Thickness of cuticle Thickness of crystal- bearing layer 15-20 (A 5- 8 iJL 5-10 IX 12-15 (X 10-12 (x 12-15 tx 30-42 (X 30-38 [X 30-38 [X 25-35 IX 20-30 (X 30-40 (X Thickness of thick-celled layer 100-120 lA 70- 87 n 55- 75 n 75-130 I* 87- 98 {1 62- 74 (fc RELATION OF PENETRATION OF TEMPERATURE TO THICKNESS OF INTEGUMENT OF CACTi To determine whether the length of time of penetration of tem- perature is influenced by the thickness of the integument or not the following experiment was performed. Pieces of the integu- ment about 5 by 5 cm. in extent were dissected from the joints of all of the above Opuntias. The integument of each species was wrapped carefully around the bulb of a thermometer and tied with a thin wire. Such prepared thermometers were put quickly in large test tubes the openings of which were closed with plugs of cotton. The test tubes had been in an ice box at a temperature of 4° C. (39.2° F.) several hours before the thermometers were placed in them. Aft^r the thermometers were inserted in the test tubes and the openings closed with cotton, the Cold-Resistance; in Smneless Cacti 129 latter were placed in a glass cylinder filled with crushed ice and salt. In this way a temperature of 0° C. (32° F.) was reached easily. This experiment was repeated three times, and each time gave results showing that the rapidity of penetration of the cold is dependent upon the thickness of the integument. Fig. 5.— Apparatus used for determining the rate of psnetration of temperature through the integuments of various spineless cacti; and, also for making a comparative study of the cooling points, freezing points, and duration of freezing points of different spineless cacti. On an average it took G3.3 minutes for the temperature to penetrate Opiintia castillae and 79.3 minutes for it to penetrate 0. Ellisiana, both species of which have thick integuments. The length of time required for the other species was much shorter. The following table gives a summary of the experiment, the num- ber of minutes indicating the time required for the temperature to reach 0° C. (32° F.). 130 ^Bulletin 79 SUMMARY SHOWING TIME REQUIRED FOR A TEMPERATURE OE 0° C, TO PENETRATE DIFFERENT CACTI Name of plant Opuntia castillae 0. ficus indica, from Malta. . O. Etlisiana Opuntia sp. Burbank Special. 0. fusicaulis O. ficus indica, from Sicily I 32 First Second Third reading reading reading Mins. Mins. Mins. 73 52 65 31 39 35 79 77 82 37 33 28 35 40 41 32 48 48 Average Mins. 63.3 35.0 79.3 32.6 38.6 40.6 PHYSIOLOGICAL STUDIES In order to ascertain why these plants were injured by cold it was necessary to consider four main problems: 1. Are the plants killed at a temperature a little above the freezing point of water, as is often the case with tender greenhouse plants? 2. Is the injury caused by the freezing of water in tissues of the plant body? 3. May the plant tissues be killed by poisoning caused by the cell sap becoming more and more concentrated, as its wa- ter gradually changes into ice? 4. May the protoplasm withstand only certain temperatures below 0° C. ^32° F.) without injury, and after having exceeded that degree of cold, be killed? EFFECTS OF TEMPERATURE AT THE MELTING POINT OF ICE ON TH^ ^ . TISSUES Beginning with the first problem — stems and parts of stems of Opuntia castillae, 0. fusicaulis, 0. Ellisiana, Opuntia sp. Burbank Special, O. ficus indica from Malta and from Sicily were put in crushed ice in an ice box, where they remained for two days at a temperature of 0° C. (32° F.). After six hours the material was exam- ined, but was not at all injurjed. After 48 hours the material was again examined, but none of the stems were killed or apparently injured. Parts of these cactus joints were then placed in a constant temperature oven at a temperature of 60° C. (140° F.) for six hours, at the end of which time they showed no apparent injury. It is evident, therefore, that these plants can endure a considerable range of temperature without injury. It is quite possible, how- ever, that they might have been injured by this latter temperature had it been continued for a longer time. Cold-Resistance in Spineless Cacti 131 Slides of tissue of cactus plants were put for different periods on ice, but the cells were not damaged. This suggests that the cells are not injured with the temperature of melting ice. The first problem is, therefore, disposed of. Protoplasmic Movements It is interesting to observe the movements of the protoplasm of the living cdls of cactus stems under different temperatures. In studying a tissue at room temperature, which was about 29° C, (84.2° F.), the streaming of the protoplasm is noticeable through the rapid movements of the microsomes and physodes; th^^ large chloroplasts also, and not infrequently the nucleus, are often seen to move for a short time. When the temperature is gradually lowered by putting ice arDund the slide, the protoplasmic movement becomes slower and slower until it finally stops. The location of the different protoplasmic structures and the size of the cells, how- ever,remain the same ; and the cells have not lost their turgor. After the ice has melted, the water around the slide soon takes the tem- perature of the surrounding air and the protoplasm in the cells again begins its movements. determination of the cooling and the freezing points in cacti The second problem is very interesting and raises several addi- tional questions. It takes into consideration the behavior of the plant at temperatures below the freezing point. The following experi- ment was performed in this connection. Pieces about 10 by 10 by 25 millimeters in size were cut from the stems of cactus plants. In the middle of these the bulb of a thermometer was inserted. The thermometer, with the piece of cactus in position, was next placed in a large test tube and the opening closed with a plug of cotton batting. This test tube was next placed in a mixture of ice and salt so that a temperature of —20° C. (—4° F.) was reached. The thermometer soon dropped from the temperature of the cactus to —1° or —0.75° C. (30.2 or 30.6° F.) the cooling point, and then rose quickly to 0.25° to 0.50° C. (32.45° to 32.9° F.). After this the temperature remained for a considerable time at 0.50° to — 1.50° C. (32.9° to 29.3° F.). This latter temperature is known as the freezing point and has a remarkably small variation with the different species of cacti that were studied. The length of time, however, during which this temperature is maintained by the different species of cacti varies considerably. After the temperature remains 132 BuivLETiN 79 at this freezing point for some time, as will be noted late r, it drops fairly regularly to the temperature of the air in the test tube, which was kept usually at —20° C. (—4° F.). COMPARISON OF COOLING POINTS, FREEZING POINTS, AND DURATION or FREEZING POINTS IN DIFFERENT SPINELESS CACTI 1. Opuntia castillae. — The cooling point was reached at — 1° C. (30.2° F.) and rose to —0.50° C. (31.1° F.), the so-called freezing point, where it remained from 35 to 44 minutes, when the temperature dropped for a while slowly, and afterwards rapidly, until ■ — 20°C. ( — 4° F.) was reached. 2. 0. ficus indica from Malta.- — The cooling point was reached at - — ^.75° C. (30.65° F.). The temperature rose now quickly to — 0.25° C. (31.55° F), the freezing point, where it remained from 12 to 18 minutes, then the temperature dropped quickly to ■ — 20° C (—4° F.). 3. 0. Ellisiana reached its cooling point at ■ — 0.75° C. (30.65° F.) and then went up to — 0.50° C. (31.1° F.). Afterward it remained at a temperature between —0.50° and —0.20° C . (31.1° and 31 .64° F.) for about 20 to 28 minutes, when it began to drop rapidly. /■ .u ,,.; -fr . , ill Sb rf Is t g j li| \ 1 X ! ' '" " ■~ 1 s 1 ■ \ jL lit m 1 r ; fffi! 1 ::!;';:l!!!tlltfflff fflffl It ^;|!F?!Hiliiti»tt j !.,:Kr[ Jit It' j a ifflili F ig. 6. — C-irvi showing cooling point, freezing point an;l duration of freezing point of Opuntia castillae. Cold-Resistance in Spineless Cacti 133 SmmSm««^«»^ Fig. 1 . — Curve showing cooling point, freezing point and'duration of freezing point of Opuntia Ellisiana. /'♦ *' ♦o *•' r ^ J ■' Fig. 8. — Curve showing cooling point, freezing point, and duration of freezing point of Opuntia sp. Burbank Special. 134 Bulletin 79 4. Opuntia sp. Burbank Special has a cooling point of — 1° C. (30.2° F.) and a freezing point of —0.20° C. (31.64° F.),where it remained from 22 to 30 minutes and dropped afterwards rapidly. 5. 0. JusicauUs has a cooling point of — 1° C. (30.2° F.) and a freezing point of — 0.50° C. (31.1° F.), where it remained from 45 to 64 minutes, and then dropped rapidly. 6. O.ficus indica from Sicily reached its cooling point at — 0.75°C„ (30.65° F.) and its freezing point at —0.50° C. (31.1° F.), where it remained from 30 to 38 minutes and dropped afterwards until the temperature of the test tube was reached, which was — 20° C. (—4° F.). SUMMARY OF RESULTS OF TEN EXPERIMENTS WITH EACH OF SIX SPECIES AND VARIETIES OF OPUNTIA Name of plant 0. castillae 0. ficus indica, Malta. O. Ellisiana Opuntia sp. Burbank Special O. fusicaidis O. ficus indica, Sicily. Cooling point -l.UO -0.75 -0 . 75 -1.00 -1.00 -0.75 °F. 30.20 30.65 30.65 30.20 30.20 30.65 p'reezing point " c. -0 50 -0.25 -0.50 -0 . 20 -0.50 -0.50 " F. 31.10 31.55 31.10 31.64 31.10 31.10 Time of freezing Mins. 35-44 12-18 20-28 22-30 45-64 30-38 Temp, of the air °c. —20 —20 —20 —20 —20 —20 ° F. —4 —4 —4 —4 —4 —4 Results of other workers It is interesting to compare the above study with the results of other experimenters with cacti and also with different plants. The different species show a considerable range of temperature for the freezing point and also for the duration of the freezing point. The limited work that has been done on the species of cacti by other investigators gives practically the same freezing point as found in the writer's experiments. This would indicate that cacti have their own biophysical peculiarities. Muller-Thurgau* in experiments with Phajus grandifoUus , a tropical orchid, shows that the temperature of the plant in an environment of —7.5° C. (18.5° F.) drops regularly from 15° C. (59° F.) to— 2.5° C. (27.5° F.); after this it drops slowly until —6° C.^21.2° F.) is reached. The temperature then rises to —0.5*' C. *Ueber das Gefrieren und Erfrieren dcr Pflanzfen, Landw. Jahrb. ISSO. Cold-Resistance; in Spineless Cacti 135 <^31.1° F.), where it remains for about 4 minutes, after which it drops regularly and gradually to — ^6.75'^ C. (19.85° F.) in 41 minutes. In his experiment with potatoes, MuUer-Thurgau found that the temperature dropped regularly from 15° C. (59° F.) to 2° C. (35.6° F.) From the latter to —3.3° C. (26° F.) it dropped more slowly ; after that the temperature rose rapidly to 2° C. (35.6° F.) and remained there for 70 minutes. With this the air in the experiment was changed to 15° C. (59° F.) so the freezing experiment could be carried no further. MuUer-Thurgau gives a long list of freezing points of different plants, from which several well-known species have been selected for comparison with the freezing points of cacti. TABLE OF FREEZING POINTS OF DIFFERENT PLANTS. Cooling point Freezing point Temp, of air Remarks °c. ° F. °c. ° F. °c. ° F. Opuntia maxima. . —1.16 29.91 —0.15 31.73 —4.50 23 . 90 Stem. Cineraria jiybrida —2.40 27.68 —2.00 28.40 —7.50 18.50 Very young leaf. Datura arhorescens —4.30 24.26 —1.25 29.75 —5 . 50 22.10 Old leaf. Ficus repens —7.10 19.22 —4.05 24.71 —14.5 5.90 Young leaf. Ficus repens —8.00 17.60 —8.00 17.60 —11.0 12.20 Old leaf. Fuchsia fulgens. . . —2.35 27.77 1.75 28.85 —8.5 16.70 Young leaf. Hedera helix —3.45 25.79 —2.18 28.07 —4.2 24.44 Old leaf. Bean —6.30 —6.48 20.66 20.33 —1.10 —0.55 30.02 31.01 —8.0 —7.50 17.60 18.50 Leaf. Sempervivum tabu- Fresh leaf. laeforme. Thuyopsis dolo- —6.20 20.84 —0.57 30.97 —16.0 3.20 Twig. brata. Corn —7.35 18.77 —2.60 27.32 Fruits of: Grape (Riesling) —7.85 17.87 —3.10 26.42 —12.0 10,40 Apple (Canada —2.10 28.22 —1.40 29.48 —14.0 6.80 Reinnette) Potato, contain- —4.30 24.26 —1.40 29.48 —9.00 15. 8o ing sugar. Comparison of results The results of the writer's work with cacti closely resemble those which MuUer-Thurgau obtained with Opuntia maxima. He obtained a relatively high cooling point, and a freezing point a little below the temperature at which water freezes, while with other plants he obtained both a lower cooling point and a 136 BuLi^ETiN 79 relatively lower freezing point. Corn, with a cooling point of — -7.35°C. (18.77° F.) and a freezing point of —2.60° C. (27.3° F.), and fruits of grapes, with a cooling point of — 7.85° C. (17.87° F.) and a freezing point of — 3.10° C. (26.4° F.), may be cited as examples. The above data follow very distinctly the laws of the freezing of solutions, as stated by Raoult, who says: "If one dissolves in any selected solvent equimolecular quantities of different sub- stances, the freezing point is lowered the same amount in all cases." Also, " the lowering of the freezing point is proportional to the size of the molecule of the dissolved substance."* The different temperatures at which cell-sap freezes is here very apparent. Corn and grapes contain a high percentage of organic and inorganic matter in the water of the vacuoles. It is the great amount of sugar in the grape which gives to the fruit so low a freezing point. , Opuntia maxima, with which Muller-Thurgau worked, and the spineless cacti, with which the writer worked, on the other hand, have freezing points very little below that of pure water. It follows, therefore, that the dissolved matter in the large amount of water in the cacti is very small. This is not surprising when we consider that the water in these plants is principally storage water, which has been gathered by the plants during the rainy seasons and which enables the plant to carry itself through long droughty periods such as are characteristic of the arid plains of the southwestern parts of the United States and of adjacent Mexico. On the other hand, the water of corn, grape, and similar plants, is imbibition water which serves to carry the inorganic solu- tions from the roots to the young cells, and also assists in distrib- uting different organic soluble substances from one part of the plant to another. It also takes part in the synthesis of carbohydrates. In other words, it is water that is used for the time being and must be replaced regularly. This constitutes the important difference. Another factor worth noting is the length of time required to convert all the water of the plant into ice, as is shown in the table and in Figs. 6, 7, and 8. It is not the same with all species of cacti. Opuntia fusicaulis took 45 minutes or more, and in one case 64 minutes, while 0. ficus indica, which was introduced from the island of Sicily, required only 12 to 18 minutes. *See also W. Nernst, Theoretical Chemistry. 1899, pp. 116 and SOO. Cold-Resistance in vSpineless Cacti 137 The above facts, however, are entirely independent of both cooling point and actual freezing point, and, as we will see later, are also independent of the degree of cold required to kill the plants. Without doubt the duration of the freezing point is related directly to respiration, which the plant is able to perform at low temperatures until the water is entirely frozen, at which time the protoplasm probably becomes dormant. This freezing of the water takes place at the end or about the end of the nearly straight line in the diagrams. As already noted, this line is shorter in some species of cacti than in others. The curve is quite constant for the same species, but there appears to be no relation be- tween the length of this line and the, cold resistance of a species. 1£. Fig. 9. — Curves showing the freezing of dead tissues of spineless cacti, including Opuntia sp.Burbank Special, O. fusicaulis and O. ficus indica. Compare with curves of living tissues. It is interesting to observe the character of the curve when pieces of recently killed cactus stems are substituted for the living ones. These show a very much shorter line, which soon becomes strongly curved downward, as shown in Figure 9. This line is practically the same for Opuntia ficus indica, Opuntia sp. Bur- bank Special, and 0. fusicaulis after the freezing point is reached. Similar results were obtained with other species. 138 Bulletin 79 The similarity of the curves of freezing in the dead tissues of the cacti is due purely to a physical condition, while the differences in the curves of the living tissues is due t^ a biophysical condition. The absence of living protoplasm in the cells appears to be respon- sible for the differences observed in the curves. EFFECTS OF FREEZING THE TISSUES Taking up the third problem, it is well known that in freezing plants ice generally appears first in the intercellular spaces of the tis- sues. Since these intercellular spaces normally contain air and not water, the presence of crystals of ice in them suggests that previous to freezing the water must have been secreted from neighboring cells with the lowering of the temperature. This low temperature causes the water to separate from the .cell solutions and freeze. This leaves the remaining cell-sap solution stronger in soluble substances, and consequently a lower temperature is required to cause more of the water to separate and freeze. It is easily under- stood that the cell contains a stronger sap solution after a part of the water has frozen. In some plants this solution may become strong enough to kill the protoplasm of the cells affected. The small amount of material which is dissolved in the storage water in cacti is so unimportant that it can do little or no harm to the protoplasm of the cells, even when relatively low temperatures have caused a large amount of the water of the cell-sap solution to be secreted and frozen. With certain precautions the behavior of the frozen plant tissues may be studied easily under the microscope. A Ganong tempera- ture stage which serves as well for studying the behavior of the protoplasm under low as under high temperatures was used. F'or this study the stage was fixed in the usual way to the microscope, and the triangular copper basin was filled with a mixture of cru.shed ice and salt. To lower the temperature further, a vessel was filled with the same freezing mixture, in which the triangular copper basin of the temperature stage was partly embedded. In this way the metallic part of the temperature stage, which is protected by a thick felt covering to prevent radiation, and which is located directly above the stage of the microscope, could be kept easily at a temperature of — 5° C. (23° F.). The temperature, however, could not be reduced below this point. The holes in the sides of the temperature stage where the glass slide is inserted were filled with cotton batting to assist in maintaining a uniformly low tern- Cold-Resistance in Spineless Cacti 139 perature. With this it was easily possible to study the changes taking place in the protoplasmic cells at the low temperature noted. Ice, in the form of both needle and disk-shaped crystals, was first observed to form on the walls in the intercellular spaces between the cells and above them. When the freezing mixture was removed and also the small pieces of cotton from the openings, the ice that had formed in the intercellular spaces melted gradually, and prac- tically all the water resulting was absorbed again by the cells. With the low temperatures no movement of the protoplasm could be seen, but with the gradual rise of temperature following the removal of the bits of cotton and the freezing mixture, a slow movement of the protoplasm was observed, which became faster with the rise of temperature of the slide. This experiment was repeated several times with the same section of tissue without killing the protoplasm. •»>«»l>f*w--: ■'• Fig. 10.- "Apparatus uted fcr studying the effects of low temperatures and of freezing on the Drotoplasm of cacti. The same results were obtained by putting parts stems in test tubes at temperatures slightly below point of water. This was repeated several times, sections in each instance to come to the temperature without injuring the protoplasm. These experiments the protoplasm in the cells of the cacti was not injured (1 result of the separation of at least a large part of the of the cactus the freezing allowing the of the room, proved that ) either as a water from 140 Bulletin 79 the cell sap, and its freezing in the intercellular spaces, or (2) by the condensation of the cell sap as a result of the water being removed. The second and third problems, are, therefore, answered. EFFECTS OF COLD ON THE PROTOPLASM The only other cause that might result in the death of the plant or parts of the plant is the inability of the protoplasm to withstand temperatures below a certain point. It is not to be presumed that the protoplasm would be killed as a result of the destruction of the enzymes of the cell, since these are able to with- stand low temperatures uninjured. To determine this, pieces of stems of the various species and varieties of spineless cacti were subjected to a killing temperature of — 20° C. ( — 4° F.). To do this, a large-sized ice-cream freezer containing the ordinary freezing mixture of ice and salt was used. This gave a temperature of — 20°C.( — 4°F.). The cactus stems were allowed to remain at this temperature for 48 hours, and the ice and salt mixture was replenished from time to time. When removed from the freezer the stems were frozen hard, and upon thawing gradu- ally it was evident that they had been killed, since they had lost their turgor, and the water in the stems was not absorbed by the protoplasm. Other tests also indicated that the protoplasm was dead. Along with this experiment small pieces of the cactus stems were fitted carefully about bulbs of thermometers which were inserted in large test tubes, the ends of which were closed with cotton bat- ting. These test tubes were placed in a mixture of ice and salt and allowed to remain until the temperature reached ^20° C. (—4° F.). This length of time, as before noted, varied with different species. When this temperature had been reached, the thermometers with the pieces of cacti attached were removed, and the protoplasm was studied. The pieces of cacti were frozen hard. After thawing gradually there was every indication that the protoplasm was dead. The cells had lost their turgor, and the protoplasm did not absorb water. Microscopic study showed that the cells were plasmolyzed and the protoplasm had collected toward the centers of the cells in shapeless masses. The nuclei were shrunken, and the chloroplasts had lost, in part, their roundish shape. This p'" '■"iplasm stained immedi- ately with a solution of eosin in water, which condition, will not obtain with living protoplasm. The cells had lost their former outline and the intercellular spaces were greatly enlarged. This latter. COLD-RESIStANCE; IN SPINELESS CaCTI 141 however, would not result in the death of the cells, as plant tissues which have been frozen but not killed often show more or less en- largement of the intercellular spaces. This was true with all spe- cies of cacti studied. It is clear, therefore, that the protoplasm was killed by certain low temperatures which it could not withstand. With our present knowledge of chemical and physical phenomena of life, it is not possible to study the internal behavior of the pro- toplasm at the time when the temperature is fatal. It is of both scientific and economic importance to determine at just what temperatures these different species are injured and killed by the cold, since some are able to withstand lower tempera- tures than others. When a cactus plant is injured somewhat — i. e., only parts of the joints are killed, the plant may recover and make good growth the following season. In the numerous experiments performed in this part of the work, the results of which are sum- marized in the table below, it was found that the same low tem- perature which would injure a piece of cactus stem would kill it if continued for some time, or if repeated five to eight times. Such a temperature, therefore, must be regarded as the killing tempera- ture. The less hardy varieties, like Opuntia ficus indica and Opuntia sp. Burbank Special, were injured with temperatures between —5° and — 6° C. (23° and 21.2° F.) and were killed when subjected to these temperatures several times. On the other hand, Opuntia castillae and 0. Ellisiana were injured at temperatures of — -14° and —16° C. (6.8° and 3.2° F.), respectively. It is interesting to observe that there is no great difference between the temperature which will injure a plant and the temperature which is fatal to the plant in a short time. TABLE SHOWING TEMPERATURES AT WHICH PIECES OF CACTUS STEMS WERE DAMAGED AND ALSO KILLED OUTRIGHT, WITH DIFFERENCES IN TEMPERATURE Name of plant Plant damaged Plant killed outright Differ- ence in t.emp. Temp, of sur- rounding air Opuntia castillae Opuntia sp. Burbank Special 0. ficus indica, Malta. 0. Ellisiana 0. fusicaulis 0. ficus md'ca, Sicily . °c. —14 — 6 — 5 —16 — 8 — 5 ° F. 6.8 21.2 23.0 3.2 17.6 23.0 °c. —17 — 8 — 6 —18 —10 — 8 ° F. 1.4 17.6 21.2 —0.4 14.0 17.6 ° C. 3 2 1 2 2 3 °c. —20 20 —20 —20 —20 —20 °7^. —4 —4 —4 —4 — 4 —4 142 Bulletin 79 From the above table it is observed that Opuntia castillae and O. Ellisiana are resistant to lower temperatures than any of the other species experimented with, being injured at -14° and -16° C. (6.8° and 3.2° F.), respectively, and that Opuntia ficus indica from both Malta and Sicily and Opuntia sp. Burbank Special are least resistant to cold. These species show injury at temperatures of —5° and— 6° C. (23° and 21.2° F.), respectively. Another species, Opuntia fusicatilis, was injured at a temperature of — 8° C. (17.6° F.). As will be shown later, these results coincide with observations made under field conditions during the winter of 1915-16. In this work it must be remembered that only pieces of cactus stems were used and that for the most part these were protected by the thick integument of the cactus on but two sides, above and below, while the cut surfaces were naturally without the protection of the integument. Since experiments, the results of which are given on page 10, indicate that a considerable length of time is required for the low temperatures to penetrate the integument, it is to be inferred that uncut joints would resist the same low temperature for a greater length of time. This, however, represents only difference in the length of time required for the penetration of the low temperature. It would not enable the protoplasm to endure a greater degree of cold. BEHAVIOR OF PLANTS OF SPINELESS CACTI GROWING IN THE INTRO- DUCTION GARDEN AT THE UNIVERSITY FARM DURING THE WINTER OF 1915-1916 The first frost of any note during the winter of 1915-16 occurred on the night of December 16-17, when the temperature dropped to —1.50 C. (29.3 F.). None of the species of cacti was injured. A little later there were several cold nights when the temperature dropped as low as —4° and —6° C. (24.8° and 21.2° F.). With these temperatures some injury was don^ to plants of Opuntia ficus indica and Opuntia sp. Burbank Special. This was particularly true of the younger and partly immature joints, which lost their color and turgor and began to shrink. On December 28, the temperature dropped to — 7.20° C. (19.04° F.) on the University grounds, the corresponding tempera- ture at the University Farm being one or two degrees lower. With this, considerable damage was done to plants oi Opuntia fi,cus indica and Opuntia sp. Burbank Special growing at the University Farm. The ends, also, of the less mature joints of Opuntia fusicaulis Cold Resistance in vSpineless Cacti 143 were injured. No damage was done to plants of Opuntia castillae or O. Ellisiana, which remained in excellent condition throughout the winter. Plants of Opuntia castillae growing on the University grounds and also in several parts of Tucson showed no injury from cold. The lowest temperatures recorded on the University grounds during the months of January and February, 1916, were — -5° C. (23° F.) on the night of January 11-12, and —5.6° C. (21.9° F.) on the night of February 1-2. There are no temperature records at the University Farm for these dates, but it is safe to assume that the minimum temperatures there were one or two degrees lower than those given above. During these cold nights plants of Opuntia ficus indica and Opuntia sp. Burbank Special were slightly injured. SUMMARY 1. In this study it has been found that the species of spineless cacti having relatively thick integuments are more resistant to low temperatures than those having somewhat thinner integuments, as the penetration of low temperatures through a thick integument is slower than through a thinner one. The term integument is used here to include the cuticle, epidermis, crystal-bearing layer, and several layers of thick-walled cells lying immediately below. The thick integument may be an accidental rather than a developed character. Since our lowest winter temperatures are often of short duration, a cactus plant having a thick integument may pass through such a period practically uninjured, even though the tem- perature may be low enough to be fatal to the protoplasm. A thick integument protects a cactus plant against sudden and severe temperature changes at any season. 2. The freezing point of the cell-sap of the cactus plant is very little below 0° C. (32° F.), the freezing point of pure water. This suggests that the soluble substances in the cell-sap of cacti are Tery diffuse. The ordinary cactus contains as much as 90 per cent water. 3. The collecting and freezing in the intercellular spaces of the water from the cells is not in itself particularly harmful to the plant. Neither is the protoplasm poisoned with the. concentration of the cell-sap solution as a result of at least a part of the water being withdrawn and frozen. 4. The protoplasm of these plants can withstand without injury a certain low critical temperature, but a temperature below this 144 Bulletin 79 is fatal. Injury b)^ frost of a normal cactus plant — i. e., one healthy and of mature growth, is due to the temperature faUing below the point which the protoplasm can endure. 5. This study indicates that Opuniia castillae and 0. EUisiana are resistant to lower temperatures than the other species of spine- less cacti studied, being injured at temperatures of — 14° and — IG' C. (6.8° and 3.2° F.), respectively, while Opuntia ficus indica and Opuniia sp. Burbank Special were injured with temperatures of —5° and 6° C. (23° and 21.2° F.), respectively. These results agree in general with observations made on these same species under field conditions. 6. The temperature which damages a plant to any extent will kill the plant if continued long enough or if repeated several times. This may be regarded as the "killing" temperature. 7. The reason that one species of cactus endures more cold than another is because of a difference in the character of the protoplasm, due allowance being made for the thickness of the integument when the cold extends over only a short period. University of Arizona Agricultural Experiment Station Bulletin No. 80 Reprinted from University of California Publications in Agricultural Sciences, Vol. 1, No. 12, being No. 4, co-operative, between other institutions and the University of Arizona Agricultural Experiment Station Root tip of corn grown in water culture and poisoned by l:200fl',000 of Cu in OuSO^ solution. Copper colored red by means of potassium ferrocyanide. • Red shows black in photomicrograph. X 53 diam. CERTAIN EFFECTS UNDER IRRIGATION OF COPPER COMPOUNDS UPON CROPS By R. H. Forbes Tucson, Arizona, December 15, 1916 UNIVERSITY OF ARIZONA AGRICULTURAL EXPERIMENT STATION Bulletin No. 80 Reprinted from I'liiversity of California Publications in Agrioultural Sciences. "\'ol. 1. Xo. 12, being No. 4, co-operative, between other institutions and tlie University of Arizona Agricultural Experiment Station CERTAIN EFFECTS UNDER IRRIGATION OF COPPER COMPOUNDS UPON CROPS BY R. H. Forbes TUCSON, ARIZONA, DECEMBER 15, 1916 LIBRARY NEW YORK OARDSiV UNIVERSITY OF CALIFORNIA PRESS BERKELEY UNIVERSITY OF ARIZONA AGRICULTURAL EXPERIMENT STATION GOVERNING BOARD (Regents of the University) Ex Officio Hon. George W. P. Hunt Governor of the State Hon. Charles 0. Case Supt. Pub. lustruction Appointed by the Governor of the State Frank H. Hereford Chancellor William V. Whitmore, A. M., M. D Treasurer William J. Bryan, Jr., A. B Secretary Lewis D. Ricketts, Ph. D Regent William Scarlett, A. B., B. D Regent Roderick D. Kennedy, M. D Regent Rudolph Rasmussen Regent Frank J. Duffy - Regent RuFUS B. VON KleinSmid, a. M., Sc. D President of the University AGRICULTURAL STAFF Robert H. Forbes, M. S., Ph. D Director John J. Thornber, A. M Botanist Albert E. Vinson, Ph. D Biochemist Clifford N. Catlin, A. M Assistant Cliemist George E. P. Smith, C. E Irrigation Engineer Arthur L. Enger, C. E Assistant Engineer George F. Freeman, B. S Plant Breeder Walker E. Bryan, M. S Assistant Plant Breeder Stephen B. Johnson, B. S Assistant Horticulturist Richard H. Williams, Ph. D '. Animal Husbandman Walter S. Cunningham, B. S Assistant Animal Husbandman John F. Nicholson, M. S Agronomist Herman C. Heard, B. S. Agr -■ Assistant Agronomist Austin W. Morrill, Ph. D Consulting Entomologist EsTES P. Taylor, B. S. Agr Director Extension Service George W. Barnes, B. S. Agr Livestock Specialist, Extension Service L. S. Parke, B. S Boys and Girls State Club Agent Edith C. Salisbury, B. D. S Home Economics Specialist Arthur L. Paschall, B. S. Agr : County Agent, Cochise County Charles R. Fillerup, D. B County Agent, Navajo-Apache Counties Alando B. Ballantyne, B. S County Agent, Graham-Greenlee Counties John R. Towles Secretary, Extension Service Frances M. Wells Secretary, Agricultural Experiment Station The Experiment Station offices and laboratories are located in the Uni- versity buildings at Tucson. The new Experiment Station Farm is situated two miles west of Mesa, Arizona. The date palm orchards are three miles south of Tempe (cooperative, U. S. D. A.), and one mile soutlnvest of Yuma, Arizona, respectively. The experimental dry-farms are near Cochise and Prescott, Arizona. Visitors are cordially invited, and corresi^ondence receives careful at- tention. The Bulletins, Timely Hints, and Reports of this Station will be sent free to all who apply. Kindly notify us of errors or changes in address, and send in the names of your neighbors, especially recent arrivals, who may find our publications useful. Address, THE EXPERIMENT STATION, Tucson, Arizona. PREFACE Two of the great industries of the Rocky Mountain region, both of which have developed within comparatively recent years, are copper mining and irrigation farming. Commercially, these important industries have every reason for harmony with each other. The operations of the copper miner build up busy cities, initiate improvements in transportation and develop populations which must be fed. The irrigation farmer, on the other hand, produces abundant and wholesome supplies of foodstuffs upon which copper-mining communities depend and in return for which they pay good prices. Incidentally, however, to the rapid expansion of these two industries in Arizona and elsewhere in the west, points of contact have developed requiring adjustment. One of these has been in connection with the disposition of min- ing wastes, including smelter gases and tailings from which the values have been abstracted. In relation to tailings, enormous quantities of which are produced from low-grade ores, consider- able study has been devoted in Arizona by scientific agencies and by the copper companies themselves, to the problem of their satisfactory disposal. The object of such disposal is, on the one hand, to keep injurious substances, both insoluble and soluble, away from irrigated crops and, on the other hand, to make some use of them by the mines themselves. The result of these studies has been, thus far, to devise economical means for impounding almost the whole of the solid wastes from some of the mines, thus avoiding injury to sub- jacent lands and conserving such values as may yet remain unextractecl in the ores. It seems likely, in fact, that by means of improved methods now under consideration, these values may be economically reclaimed. The question of the toxic effects upon crops of soluble salts of copper which cannot be withdrawn from solutions that escape into irrigating streams, is the one with which this publication is mainly concerned. The outcome of the attention which has l^een devoted by farmers and copper companies to the "tailings question" in Arizona is a happy solution of a once formidable controversy; and the establishment of a precedent wiiich will be of great value in time to come in the adjustment of similar differences throughout the Rocky Mountain region. CONTENTS PAGE Part 1. — ExPEKiiiEXTAL Work 145 Iiitioduction 145 Solid wastes 146 Soluble copper compounds 148 Distribution of copper compounds throughout the Clifton-Morenci mining and Gila River irrigated district 150 Sources of copper 150 Processes by which copper is added to the water supply 151 Table of solubilities of copper compounds 152 Copper in ores and tailings from Clifton-Morenci district 155 Dissolved copper in river, irrigating and ground waters below the Clifton-Moreuci district 15(5 Copper in ores and tailings from Clifton-Morenci district 155 Miscellaneous soils unaffected by mining detritus 159 Copper in vegetation from upper Gila farms 159 Copper in vegetation from other localities 160 Copper in flesh and bones of a pig 161 Distribution of copper in plants with root systems exposed to cop- per compounds 162 Corn plants grown in soils containing copper 162 Water cultures 166 Toxicity of copper solutions to plant roots in water culture 168 Stimulation effects in water cultures 171 Effects of soil upon toxicity of copper solutions 175 Irrigation experiments 177 Cultural experiments 181 Pot cultures with treated soils 181 Pot cultures with field soils 186 Pot and plot cultures 188 Field samples of soils and vegetation 189 Use of copper sulphate to kill moss in irrigating ditches 192 Physiological observations on toxic effects of coi)per salts 193 Quantitative Avork 193 Reactions of copper with growing points 199 Varying resistance of individual cells to copper 203 Diagnosis of copj^er injury 203 Part II. — General Discussion 207 Preliminary statement 207 Accumulations of copper 207 Possible effects upon health 209 Amounts and significance of copper in aerial vegetation 210 Amoxuits and significance of copper in root systems 212 PAGE Rclatiou.s between aniuunts of copper in root systems and injury to plants 215 Pathological effects ' 216 Soil conditions relating to toxic effects of copper upon plants ...- 217 Stimulation 219 Field observations 221 Effects of river sediments 222 Effect of cultivation upon alfalfa ,- 223 Summary 227 Part III. — Appendix 229 Methods of analysis , 229 Reagents and apparatus 229 Manijiulation 229 The determination of copper in small amounts of plant ashes 232 Bibliography 236 ILLUSTRATIONS PLATES PAGE Plate I. — Corn root tips killed in a solution of 1 part copper to 100,000 of water, and colored by (1) caustic potash, violet; (2) hydrogen sulphide, brown; (3) potassium xanthate, yellow; and (4) potas- sium ferrocyanide, red Frontispiece Plate II. — Eoot system of corn plant injured by .1 per cent of copjier in the soil, with normal corn root system for comparison 204 Plate III.— Individual roots of corn injured by .1 per cent of copper in the soil ; with normal roots for comparison 204 Plate IV. — Thickened rootlets and proliferated root tips of corn in- jured by .1 per cent of copper in the soil ; with normal rootlets and root tips for comparison 204 FIGURES Fig. 1. — General map of Clifton, Morenci, and Gila River District, Arizona 147 Fig. 2. — Detail map of the Gila River irrigation district, Graham County, Arizona 154 Fig. 3. — Corn cultures gi'o'wn in University of Arizona well water, containing .03 to 3. parts per million of copper as basic carbonate .... 166 Fig. 4. — Bean cultures showing effects of varying concentrations of copper in distilled water and in solutions of mixed salts 169 Fig. 5. — Diagram of pot culture irrigated through 2-inch pot.— 177 Fig. 6. — Wheat and barley irrigated with copper solutions filtered through soil, and ■^^•ith well water 180 Fig. 1 .■ — Bean cultures grown in soils containing .0 to 1.5 per cent copper as precipitated carbonate 182 Fig. 8. — Corn cultures grown in soils containing .0 to .2 per cent cop- per as precipitated carbonate 182 Fig. 9. — Corn cultures grown in soils containing from .01 to 1 per cent copper as sulphide 183 Fig. 10. — Corn cultures growTi in soils containing .0 to 1. per cent cop- per as silicate 185 Fig. 11. — ;Pot cultures of corn in field soils containing tailings 186 Fig. 12. — Showing effects of copper influenced by tilth of soil 187 Fig. 13. — Photomicrograph of root tip of corn grown in water culture and poisoned by 1:200,000 of copper in solution 202 Fig. 14. — Tangential longitudinal section of corn root groAvn in soil containing .1 per cent of copper as copper sulphate. (X 300 diam.) 204 Fig. 15. — Diagram showing root systems under influence of tailings blanket 222 Fig. 16. — Diagram showing yields of alfalfa from head to foot of a land damaged by tailings in 1905; and the same land in 1916 after disc harrowing annually 226 -■■•-.. \ ■■ ■,••>■ " ■■/., ''^^«.:'i.f.- i- f *^:mj.T./t^- PLATE I Corn root-tips killed in a solution of 1 part copper to 100,000 of water, and colored by means of (1) caustic potash, which gives the violet biuret reaction, identifying both copper and protein; (2) hydrogen sulphide, brown; (3) potassium xanthate, yellow; and (4) potassium ferrocyanide, red. (X ± 30 diam.) CERTAIN EFFECTS UNDER IRRIGATION OF COPPER COMPOUNDS UPON CROPS By R. H. FORBES Part I.- EXPERIMENTAL WORK INTRODUCTION The region to which the studies described in this publication more particularly relate lies in southeastern Arizona in Greenlee and Graham counties and consists, first, of the Clifton-Morenci mining district and second, of the irrigated lands along the Gila River from twenty-five to sixty miles below. The Clifton-Morenci mining district is drained by Chase Creek into the San Francisco River, which in turn empties into the Gila. From the Gila, be- ginning at a point about twenty-five miles by channel below Clifton, irrigating waters are withdrawn for the use of the rich lands extending somewhat discontinuously from above San Jose to Fort Thomas, a distance of thirty miles. For about forty years, this up-stream mining district and the irrigated lands below have developed together from small beginnings into large industries. Beginning with the initiation of smelting operations on the San Francisco River in 1882, comparatively small amounts of mining detritus must have found their way into the irrigating water-supply. Following the discovery, in 1893, of immense deposits of low-grade sulphide ores in the district and the erec- tion of concentrating plants to handle them, rapidly increasing quantities of fine slimes were discharged into the stream-flow, becoming noticeable in the irrigating waters of Graham County about the year 1900. Following the observation of their pres- ence, various crop failures were attributed from time to time to the tailings, resulting finally in a request by the farmers of the district to the writer, for an examination of the facts relating to damage done by mining detritus to their irrigated crops. 146 Bulletin 80 Solid Wastes Following this request, the writer began a study of the prob- lem in May, 1904, which resulted in the publication of Bulletin 53 of the Arizona Agricultural Experiment Station, September 20. 1906. This publication established the fact that irrigating sediments, in general, may be beneficial or harmful according to their composition and physical character and to the manner of their disposition in or upon the soil. If allowed to accumulate upon the surface of the soil in the form of more or less im- pervious silt-blankets, their influence, by limiting the supply of water and air to the soil, is notably harmful. In the case of the mining wastes from the Clifton-Morenci district, which are particularly plastic and "tight" in character, the damage done was found to be greater than that resulting from sediments aris- ing from ordinary erosion. It was determined that the damage from these wastes, particularly to alfalfa and other crops which cannot receive constant and thorough cultivation, was of an in- creasingly serious character. The farmers of Graham County, represented by one of their number, finally brought suit against the Arizona Copper Com- pany. Limited, for discharging tailings into their irrigating water-supply. The case was decided in the District Court of Graham County in favor of the farmers, and an order was issued in November, 1907. effective May 1. 1908. restraining the mining companies from discharging "slimes, slickens or tailings" into Chase Creek, the San Francisco River, or the Gila River. The case was appealed to the territorial Supreme Court where, how- ever, the decision was confirmed in ]\Iarch, 1909. The case was again appealed by the Arizona Copper Company to the Supreme Court of the United States, where it was again and finally de- cided in favor of the farmers on June 16. 1913. During and since the occurrences above mentioned, large quantities of solid wastes have been impounded by the copper companies in settling basins constructed for their storage in the district. Recent investigations by the companies indicate a pos- sibility that with copper at 15 cents a pound these stored tailings, which average about 0.85 per cent copper, may be profitably I'cworked. Introduction 147 Til the long mill, therefore, it may be found that an adjust- ment based upon a complete and impartial statement of facts relating to the tailings situation is l)eneficial both to the agri- cnltnial nnd to the mining interests concerned. I V-.:ri'/',. ; A ' - > 5 '', 6';- J f "^'- ^ UTHPIC i'*"/ i'i'O'""*- V-. -/r"! "' -^S^iX-'" '■'•>. "I '..■■ ■:■•.■••...'- /• c- 1- # • \ X^lFt. GftANTf ^ ,^ I'll':'; '% /'"V"^/ - ii ''"'.:'■'>, '''■■It' y 'y O 5 fO SO ' ' ■ ' ' I ' ' I ■ I —I Fig. 1. — General map of the Clifton-Morenei and Gila River mining and irrigation district, Arizona Soluble Copper Compounds Following the disposition of mining detritus, there remained the problem of soluble copper compounds which, in small but continuously appreciable quantities, find their way with waste waters into the stream-flow of the region. These compounds 148 Bulletin 80 originate in the ores of the district and are, as in the case of the carbonates, directly soluble to a slight extent in drainage waters, especially in the presence of carbon dioxide. In other cases, the original ores are changed through the action of air into soluble substances which then escape downstream. Sulphide ores are thus oxidized in the presence of air into soluble copper sulphate. Inasmuch as it is well known that minute amounts of copper in solution are extremely toxic to plant roots directly exposed to them, some apprehension naturally existed as to the eifects of these small amounts of copper salts escaping into the water- supply of an irrigated district. In some respects, conditions were especially favorable here to the successful prosecution of a study of the foregoing ques- tion. The irrigated lands are at a distance of twenty miles or more from the smelters, so that injurious gases could not com- plicate effects upon irrigated crops. There are, also, only traces of other toxic metals to be found within the district — more par- ticularly, arsenic, antimony, and zinc. Injurious effects due to the possible toxic action of compounds originating in the mines are therefore limited to copper. Scientific study relating to toxic effects of copper upon plants under varying conditions has thoroughly established not only the fact that copper compounds are extremely toxic to plants when they obtain entry to their tissues, but also that various agencies standing between these poisonous salts and the living plant tend to prevent injury.^ Soluble copper compounds, for instance, react with carbonate of lime, commonly abundant in soils of the arid region, to form the solid carbonates of copper. ^ The partly decomposed silicates of these soils also precipitate soluble compounds of copper and mask their toxic character. Organic matter in the soil likewise holds large quantities of copper in comparatively harmless combinations. Through phj-si- cal attraction or adsorption, soluble copper compounds enter into weak combination with fine soil particles and toxic effects are thereby greatly lessened. In the presence, also, of other soluble salts, such as the various forms of "alkali" commonly found in 1 See Bibliography, pp. 236-237, references 1, 8, 14, 15, 16, 19, 34, 51. Introduction 149 the soils of the region, the toxicity of copper compounds is enor- mously lessened. The investigations recorded in this publication include: (1) Observations upon the distribution of copper in mining wastes, in irrigating waters, in soils and soil waters, in the plants, and in the animal life of the region. (2) The development of accu- rate methods for the determination of minute amounts of copper in all situations where they may occur. (3) Plant cultural work with waters and in soils in the presence of varying propor- tions of copper and under varying conditions. (4) A careful analytical study of the results of such cultures in order to deter- mine the symptoms of poisoning and the distribution of copper throughout poisoned plants; and to identify, if possible, the particular parts of plants and tissues injured by copper. (5) A physiological study of plant reactions with copper. (6) Field studies for the purpose of relating the results of laboratory inves- tigations to the question of economic injury done by copper salts to irrigated crops. By reason of interruptions due to other duties, it has required a long time to mature this investigation to the point where it seems sufficiently complete for publication. This delay, however, has given perspective to the work and, especially, opportunity to verify earlier conclusions as applied to field conditions. The writer is indebted for painstaking analytical work to Messrs. R. G. Mead, Edward E. Free, Dr. W. H. Ross and C. N. Catlin, associated with the Arizona Agricultural Experi- ment Station from time to time; and to the helpful advice of Dr. Howard S. Reed, of the University of California Graduate School of Tropical Agriculture, in connection with the physio- logical part of the work herein described. The publication, also, has been criticized to its advantage by Dr. C. B. Lipman of the University of California. 1.10 Bulletin 80 DISTRIBUTION OF COPPER COMPOUNDS THROUGH- OUT THE CLIFTON-MORENCI AND GILA RIVER MINING AND IRRIGATION DISTRICTS Sources op Copper The original source of the copper fomicl in this district, according to Lindgren.- is a Cretaceous or early Tertiary in- trusion of acidic porphyries to which, in the Clifton-]\Iorenei district, all ore deposits may be finally referred. The original porphyries contain as little as 0.02 per cent of copper ore in the form of chalcopyrite. Under the influence of superheated waters emanating from the porphyry, this chalcopyrite. together with other metallic compounds, was carried out from the molten intrusive mass into adjoining strata and there deposited, espe- cially along fissures, in the form of concentrated masses or veins of chalcopyrite and other minerals. Through erosion these de- posits were afterward subjected to atmospheric oxidation, fol- lowed by downward percolation and a period of secondary enrich- ment due to numerous reactions mainly between the oxidized compounds of copper and other minerals present. In limestones and shales, these processes resulted in the formation of oxidized ores containing azurite, malachite, chryso- colla, and cuprite. In porphyry, the main final result was chalcocite or copperglance, the principal constituent of the sul- phide ores of the Clifton-Morenci district. In general, therefore, the metasomatic changes associated, first, with superheated waters arising from the original intrusion of molten porphyry and, second, with meteoric waters percolating downward with oxidizing effects through copper-bearing rocks. 2 U. S. Geological Survey, Professional Paper No. 43, 190.5. DisTRiHi'Tiox OP Copper Compounds 151 have brought copper from a concentration of possibly less than 0.02 per cent in the original porphyry through every degree of ricluK^ss to the condition in some cases of pure copper. Processes by which Copper is Added to the Water-Supply To a slight extent, drainage waters from the ore deposits and from the mines, containing considerable amounts of copper in solution, find their way downstream. But by far the larger part of the copper which gets into the irrigating supply is derived from the ores and tailings which, in the concentrators, on the dumps, and finally in the river itself, are subjected to the action of atmospheric oxygen, and water containing carbon dioxide and various salts in solution. The residual chalcocite in tailings from sulphide .ores thus reacts with oxygen from the air and yields copper sulphate in solution. This, in turn, reacts with the excess of bicarbonate of lime ordinarily contained in the waters of tlie San Francisco and Gila rivers. The resulting basic carbonate of copper is notably soluble in water containing carbon dioxide and certain of the various salts commonly found in river waters. The residues of carbonates of copper in oxidized ores are directly dissolved in waters containing carbon dioxide and certain soluble salts. Along with minute quantities of copper thus dissolved and carried forward, pass the solid residues discharged from the concentrators — solid wastes which find their way, unchanged, downstream and finally upon the soils of irrigated fields. At this point begins another and very important series of reactions be- tween dissolved copper compounds and the soil, tending in general to withdraw copper from its solutions and precipitate it in the form of less harmful solid compounds. These are briefly referred to above and will be discussed more in detail further on in this paper. Opposing these precipitations of copper are those solvents which tend to maintain this metal in soluble form in small quantities in the soil. Chief of these is carbon dioxide, which is always present in agricultural soils in significant quantities. Of interest in this connection is the fol- 152 Bulletin 80 Compound Malachite CuC03.Cu(0H), Precipitated basic copper carbonate Precipitated basic copper carbonate Precipitated basic copper carbonate Precipitated basic copper carbonate Precipitated basic copper carbonate Precipitated basic copper carbonate Precipitated basic copper carbonate Precipitated basic copper carbonate Precipitated basic copper carbonate Precipitated basic copper carbonate Copper sulpliide; CuS Chalcopyrite CuFek Chalcopvrite CiiFeS, Malachite Chrvsocolla Cu Si Oj.n H„0 Ciipric sulphide CuS Cuprite Cu.O Cupric oxide CuO TABLE I Solubilities of Copper Compounds Cu dissolved, parts per million Solvent Water containing 0.12% carbon dioxide 29.0-31.0 Pure water 1.5 Water containing 0.12% carbon dioxide 34.8 Water containing 0.13% carbon dioxide and 0.01% sodium chloride Water containing 0.13% carbon dioxide and 1.0% sodium chloride Water containing 0.12% carbon dioxide and 0.01% sodium sulphate Water containing 0.12% carbon dioxide and 1.0% sodium sulphate Water containing 0.12% carbon dioxide and 0.01% sod. carbonate Water containing 0.12% carbon dioxide and 1.0% sod. carbonate Water containing 0.12% carbon dioxide and 0.2% calcium sulphate Water containing 0.12% carbon dioxide and 0.11% calc. carbonate Oxygen-free water 36.0 58.0 37.0 58.0 10.0 0.7 36.0 1.4 0.09 Pure water Sodic sulphide measurable amounts Anit. not stated "Insoluble in water, slightly soluble in water charged with carbon dioxide." ' ' Somewhat soluble in water with carbon dioxide ' ' Water 1 to 950,000 "Insoluble in water" ' ' Insoluble in water ' ' Reference E. E. Free, Journ. Am. Chem. Soc, XXX, 9, p. 1367 E. E. Free, Journ. Am. Chem. Soc, XXX, 9, p. 1370 E. E. Free, Journ. Am. Chem. Soc, XXX, 9, p. 1370 E. E. Free, Journ. Am. Chem. Soc, XXX, 9, p. 1371 E. E. Free, Journ. Am. Chem. Soc, XXX, 9, p. 1371 E. E. Free, Journ. Am. Chem. Soc, XXX, 9, p. 1372 E. E. Free, Journ. Am. Chem. Soc. XXX, 9, p. 1372 E. E. Free, Journ. Am. Chem. Soc, XXX, 9, p. 1372 E. E. Free, Journ. Am. Chem. Soc. XXX, 9, p. 1372 E. E. Free, Journ, Am. Chem. Soc, XXX, 9, p. 1372 E. E. Free, Journ. Am. Chem. Soc, XXX, 9, p. 1372 W. H. Ross, MSS U. S. Geol. Survey Mono^Taph XLVil, p. 1107 U. S. Geol. Survey Monograph XL VII, p. 1106 Moissan 5, p. 167 Lindgren, U. S. vjT. S. Prof, paper 43, p. 188 Comey, Diet. Solu- bilities, p. 139 Comey, Diet. Solu- bilities, p. 137 Comey, Diet. Solu- bilities, p. 137 Distribution of Copper Compounds 153 lowing table of solubilities of various compounds of copper in different solvents, made up from different sources of information. The exact determinations of solubility by E. E. Free and W. H. Ross were made to obtain data needed in this investigation. This table indicates that the carbonates and the silicate (chrysocolla) of copper, which are the compounds in which the metal must largely occur in the soil, are notably soluble in aqueous solutions of carbon dioxide.^ Large amounts of sodium chloride and sodium sulphate increase the solubility of precipi- tated basic copper carbonate. In pure water, copper compounds, so far as observed, are but slightly soluble. Fluctuations in the content of carbon dioxide and of soluble salts in soil waters, and variations in the character of the soluble salts, are shown to affect the copper content of such waters. In brief, the final effect upon plant roots of copper in the soil is the complex resultant of many opposing influences tending, on the one hand, to remove copper from solution, and, on the other, to maintain it in toxic soluble form. Observations on Hip soil usually fail to give satisfactory evidence as to the toxic or non- toxic effects to be expected from small percentages of copper that may be present. Direct chemical and physiological studies of plants afford much more satisfactory information. This mode of attack has been employed considerably in this investigation. In view of the general tendency in nature to hinder the move- ments of copper in soils and to convert it into its insoluble forms, and independently of any tendency of the plant itself to assimi- late or to reject copper, we should expect to find relatively small amounts of this element in plant tissues. The following analytical determinations of copper in ores and tailings were made in samples carefully collected by the writer throughout the district studied. In all cases, the copper was determined electrolytically, manipulations of great delicacy having been developed for the determination of the minute amounts of copper often encountered. A full statement of the methods of preparing samples for analysis, and of determining 3 Sullivan has shown that powdered silicates react with copper sulphate to withdraw copper from solution; and that this copper will then be redis- solved by a solution of potassium sulphate. U. S. Geol. Survey, Bull. 312, 1907. 154 BrLLETIN 80 o SI 3 o o g s o O "J 5^ Distribution of Copper Compounds 155 copper in ores, tailings, waters, soils, and organic materials, is to be found under "Methods of Analysis" in the appendix to this paper. For convenience in comparing widely variable amounts in the samples examined, the copper content is given in parts per million of substance. Parts per million may be reduced to percentages by moving the decimal point four places to the left. For instance, 11,600 parts per million is equal to 1.16 per cent. TABLE II Copper ix Ores and Tailings from the Clifton-Morenci Mining District Sample No. and date 3491 May 23, '04 330.S May 23, '04 3438 June 28, '05 3499 June 28, '05 D. C. Co.'s Eecords May 20, '04 3492 May 23, '04 3304 May 23, '04 3439 June 28, '05 3500 June 27, '05 3309 May 26, '04 3486 June 11, '05 3737 Feb. 22, '07 6342 Mar. 4, '16 Description of sample One (la^^ 's run of sulphide ore from from A. C. Co. 's mill in Clifton Sulphide tailings, point of discharge from A. C. Co. 's mill, Clifton Sulphide tailings, point of discharge from A. C. Co. 's mill, Clifton Sulphide tailings at Clifton coming from Longfellow mill Fine sulphide tailings at Morenci One day's run of oxidized ore from A. C. Co. 's mill at Clifton Oxidized tailings, point of discharge from A. C. Co. 's mill, Clifton Oxidized tailings, point of discharge from A. C. Co. 's mill, Clifton Oxidized tailings, point of discharge from Shannon C. Co. 's mill, Clifton Milky sediments, pure tailings from Montezuma Canal, Solomonville River sediments with tailings from Montezuma Canal, Solomonville High river sediments with muddy tailings from Montezuma Canal, Solomonville Floodwater sediments from Monte- zuma Canal, Solomonville; tail- ings from Mogollon Condition and weight taken, grams 1 air-dry 1 water-free 1 water-free 1 water-free 1 air-dry 1 water-free 1 water-free 1 water-free 2 water-free 2 water-free 15.8 water-free .5899 Cu Cu parts found, per grams million .03195 31,950 .00935 9,350 .0116 11,600 .00725 7,250 10,000 .0553 55,300 .0225 25,500 .0268 26,800 .0114 11,400 .01725 8,625 .0067 3,350 trace trace .000085 53 A point of interest to both mine owners and farmers in table II is the large proportion of copper that was discarded with tailings at the time the samples were taken. This loss, so far as these figures show, may amount to almost one-third of the copper 156 Bulletin 80 in low-grade sulphide ores (No. 3491, No. 3303), and to nearly one-half in the richer oxidized ores (No. 3492, No. 3304, No. 3439). By far the larger portion of tailings produced, however, are from low-grade sulphide ores, the wastes from which there- fore predominate, formerly imparting to river waters the whitish TABLE III Dissolved Copper in River, Irrigating, and Ground Waters below the Clifton-Morenci District Sample No. and date 34.38 June 28, '05 3439 June 28, '05 3309 May 26, '04 3486 June 11, '05 3622 June 25, '06 3737 Feb. 22, '07 Tailings 4011 Jan. 3, '09 4029 Apr. 12, '09 6342 Mar. 4, '16 3986 Jan. 2, '09 Records of Cananea C. C. Co. Jan. 4, '14 3504 Aug. 19, '05 4012 Jan. 3, '09 3526 Condition and amount taken in cc. 500 Description of sample Water mixed with sulphide tailings from A. C. Co. 's mill, Clifton Water mixed with oxidized tailings from A. C. Co. 's mill, Clifton 500 Montezuma Canal water at Solo- monville; slight rise in river 2000 Montezuma Canal at Solomonville, small flood 6000 Montezuma Canal at Solomonville, head waters clear 9000 Montezuma Canal at Solomonville, medium flood 14000 shut out of water supply May 1, 1908. Water from Montezuma Canal at Solomonville 4000 Montezuma Canal at Solomonville 3700 Montezuma Canal at Solomonville, high water 1000 Water from C. & A. Ditch, Bisbee mine waters 3500 Water from creek below concen- trator Water from Geo. Olney's well, 30 ft. deep, east of Safford, under Montezuma Canal 7000 Water from Wilson's well, one-half mile west of Solomonville under San Jose Canal 3500 Water from University well, Tuc- son, 95 ft. deep, tapping Rillito underflow 7000 Cu found, grams .0009 .0018 .0016 .0015 .00095 .0403 .00031 .0003 .00003 .00039 .0037 less than .00001 none Cu p.p.m. 1.80 3.60 .80 .25 .11 2.88 .08 .08 .03 .11 2.1 .53 less than .003 none appearance characteristic of this material. It is of interest to note in this connection that in one instance observed the tailings almost completely maintained their richness in copper between Distribution of Copper Compounds 157 Clifton and Solomonville. At Clifton, May 23, 1904, the prin- cipal discharge of sulphide tailings (3303) was observed carrying 0.93 per cent of copper. At Solomonville, three days later, the Montezuma ditch-water sediments (No. 3309), mostly of this same material, carried 0.86 per cent of copper, indicating the persistence with which the copper accompanies the wastes, with which it is associated, downstream and upon underlying irrigated lands. TABLE IV Copper in Soils Irrigated with Tailings Waters Sample No. and date 3435 May 25, '04 3434 June 10, '05 3301 Aug. 19, '05 3436 June 25, '05 3437 June 25, '05 3502 Aug. 19, '05 2381 June 5, '00 3522 Oct. 25, '05 3521 Oct. 25, '05 2763 Nov. 11, '01 1890 Apr. 20, '01 2830 Jan. 19, '00 Description of sample Top 5 in. sedimentary soil (Fred Thorstison), upper end alfalfa field west of Safford, under Montezuma Canal Top 5 in. sedimentary soil (Geo. Olney), upper end alfalfa field east of Safford, under Monte- zuma Canal Soil in place at 4 ft. depth beneath No. 3434 Top sedimentary soil (Wm. Gilles- pie), upper end of test alfalfa field west of Solomonville, under Montezuma Canal Soil in place, no sediments at sur- face of lower end of field near No. 3436 Soil in place at 4 ft. depth beneath No. 3437 Surface 12 in. from garden near Pima, Ariz., beyond tailings de- posits Top 4 in. sedimentary soil upper end of alfalfa field, Station farm near Phoenix, under Grand and Maricopa canals Deep soil, no sediments, Station farm near No. 3522 Surface 12 in. from orange orchard north of Phoenix, under Ari- zona Canal Surface 15 in. from cultivated field west of Tempe, under Tempe Canal Surface 12 in. from orange orchard northeast of Phoenix, under Ari- zona Canal Condition and weight taken, grams 96.7 water-free 96.8 water-free 96.2 water-free 96.7 water-free 94 water-free 96.1 water-free 100 air-dry 95 water-free 95 water-free 100 air-dry 100 air-dry 100 air-drv Cu found, grams .020 .0199 .0021 .0192 .0028 .001 faint trace .0003 .0003 faint trace faint trace none Cu p.p.m. 207 205 22 199 30 10 trace 3 3 trace trace none 158 Bulletin 80 Table III is of interest because it reveals quantities of dissolved copper in irrigating "and in ground waters sufficient, under proper conditions, in water cultures, to produce toxic effects upon plants.* It is noteworthy, however, that, following the order of the court, effective May 1, 1908, prohibiting the in- troduction of tailings into the water-supply, the amount of dis- solved copper in Montezuma canal waters greatly decreased, due to the decrease in quantity of sulphides whose oxidation affords the supply of dissolved copper. Other water-supplies also are found to contain similar amounts of copper, as the Calumet and Arizona mine waters, used for irrigation below Bisbee. As stated above, however, in the soil itself the toxic action of such copper solutions is enormously decreased. Naturally, the question arises as to the possibility of toxic effects in using such waters upon cultivated soils. This is discussed on subsequent pages. The proportions of copper (0.003 to 0.53 parts in 1,000.000 of water) found in the drainage beneath this irrigated district indicate that not all of the copper applied in irrigation remains in the soil. University well water at Tucson was observed to be free from this element. Soils Nos. 3435, 3434, and 3436 show maximum amounts of copper, inasmuch as they are composed to a considerable extent of tailings. The soils in place beneath these sediments, Nos. 3501 and 3502, contain much less, yet noticeable amounts of copper, most of which is retained where it first comes in contact with the top soil. It is of interest to note that the surface sediments and the deep soils of the Experiment Station farm near Phoenix, Arizona, irrigated from an entirely different watershed, also con- tain small but weighable amounts of copper. This was probably derived from mines at Globe and Jerome, Arizona, whose wastes have found their way into the drainage which supplies irrigation for Salt River Valley. The quantities observed, however, three parts copper per million of soil, are negligible. Other soils from Salt River Valley also show traces of copper. 4 See Bibliography, p. 236, references 5, 18. Distribution of Copper Compounds 159 TABLE V MiSCELLAXEOUS SOILS UNAFFECTED BY MINING DETRITUS Sample No. and date OQ Description of sample _„75 Surface 12 in. from new ground June 5, '00 near Safford, recently placed under Montezuma Ditch Surface 12 in. university ground, Tucson Condition and weight taken, grams 2253 Jan. 3, '00 3503 May 9, '05 Surface 12 in. virgin unirrigated soil, Colorado Valley bottom near Yuma 100 air-dry 100 air-dry 100 air-dry Cu found, grains none none none Cu p.p.m. none none none These determinations, made in widely separated localities, indicate the absence of copper in soils which are not immediately under the influence of mining detritus. TABLE VI Copper in Vegetation from Upper Gila Valley Farms Sample No. and date 3505 Aug. 19, '05 3512 Aug. 19, '05 3507 Aug. 20, '05 3509 Aug. 19, '05 3513 Sept. 19, '05 3739 3741 3780 3740 3738 Description of sample Alfalfa, before blooming, from upper end of Geo. Olney's field east of Safford, under Monte- zuma Ditch Alfalfa from bale grown in Lay- ton (M. B. Steele) under Monte- zuma ditch Corn in bloom, leaves only, grown in Layton (Jas. Welker), under Montezuma Ditch Wheat from stack, stalk and grain, grown in Layton (M. B. Steele), under Montezuma Ditch Mistletoe, growing on willow 25 ft. above ground, one mile east of Safford, under Montezuma Ditch Alfalfa seed, crop of 1906, grown near Pima under Smithville Ditch Alfalfa seed (Wm. Gillespie), crop of 1906, grown near Solomonville, under Montezuma Ditch Shelled corn, crop of 1906, grown at Solomonville, under Monte- zuma Ditch Shelled corn, crop of 1906, grown at Solomonville, under Monte- zuma Ditch Shelled corn, crop of 1906, grown near Pima, under Smithville Ditch Condition and weight taken, grams Cu found, grams 1206 air-dry 1359 air-dry 545 air-dry 1125 air-dry 1245 air-dry 782 water-free 843 water-free 932 water-free 874 water-free 1092 water-free .0062 .0077 .0033 .0027 .0094 .0026 .0023 .0004 .0008 Cu p.p.m. 5.10 5.70 6.10 2.40 7.60 3.33 2.72 .43 .73 trace trace 160 Bulletin 80 The prevalence of small amounts of copper in vegetation throughout this locality is shown by the figures in table VI. Samples of corn and alfalfa contained comparable quantities of copper, which, however, were exceeded by the amount found in a sample of mistletoe growing on a willow fully twenty-five feet above the ground. This is due chiefly to the perennial character of mistletoe which, therefore, has more time to accumulate cop- per. It is interesting to note also that seeds of alfalfa and corn contain less copper than corresponding foliage. Corn leaves were observed to contain 6.1 parts of copper per million parts of air-dry substance, while grain from the same locality contained from 0.73 to 0.43 parts. Alfalfa seed contained about one-half as much copper as the stalks and leaves, while wheat hay carry- ing a large proportion of grain shoived a low proportion of cop- per. These facts are probably connected with transpiration, TABLE VII Copper in Vegetation from Other Localities Sample No. and date 3508 Aug. 25, '05 Description of sample Alfalfa hay, station farm near Phoenix (two samples) Condition and weight taken, grams 2109 air-dry 1408 air-dry Cu found, grams .0021 .0031 Cu p. p.m. 1.00 2.20 3516 Oct. 25, '05 Alfalfa, before blooming, station farm near Phoenix 1106 air-dry .0011 1.00 3515 Oct. 4, '05 A-lfalfa hay, Colorado bottom, Yuma date orchard 1262 air-dry none uoue 3517 May, 1905 Barley hay, station farm near Phoenix 1304 air- dry .0002 .15 3518 Oct. 25, '05 Corn, leaves only, station farm near Phoenix 595 air-dry .0005 .84 3519 Oct. 14, '05 Corn, leaves only, grown on Eillito near old Fort Lowell 284 air-dry .0018 6.30 3529 Dec. 27, '05 Corn, leaves and bloom, same field as No. 3519 1132 air-dry .0015 1.32 3520 Oct. 14, '05 Mistletoe from cottonwood 30 ft. above ground, old Fort Lowell, near Tucson 1160 air-dry .001 .85 3989 Dec. 31, '08 Young (5 mos. old) alfalfa roots from C. & A. ranch irrigated with mine waters containing cop- per, from Bisbee 2.12 air-dry .0001 47.00 3990 Corn roots from C. & A. ranch irri- gated with mine waters contain- ing copper, from Bisbee 16.7 air-dry .00025 15.00 Distribution of Copper Compounds 161 which is maximum in leaves and quantitatively small in the fruiting parts of a plant. Additional evidence of this fact is shown in poisoned corn plants, which are discussed on a subse- quent page. Comparing the data of table VII with those of table VI, it is evident that, excluding corn and alfalfa irrigated with C. & A. mine waters, in every case except that of one sample of corn from old Fort Lowell (No. 3519) the copper in crops grown on Gila Valley farms is much in excess of that in plants coming from elsewhere for the same classes of material. The presence of appreciable amounts of copper in samples of alfalfa, corn, barley, and mistletoe also accords with the fact that the soils in which they were grown receive the drainage from copper-bearing water- sheds. The one exception, at Yuma (No. 3515) where no trace of copper could be found either in alfalfa or in soil (No. 3503), indicates that these alluvial river deposits, which have been sub- jected annually to the leaching action of enormous quantities of flood waters, have been prevented from accumulating appreciable quantities of copper. Copper in the Flesh and Bones of a Pig In order to follow the copper as far as possible in its trans- migrations, a five-months-old pig that had been born and brought up in an alfalfa pasture near Solomonville under the Montezuma Ditch, was killed and portions of the flesh and bones were taken for examination, with the following results : Condition and Cu Sample No. weight taken. found, Cu and date Description of sample grams grams p.p.m 3779 917 May 7, '07 Liver, heart, and rib meat fresh .0053 5.7S 3778 998 May 7, '07 Ribs and rib meat fresh .OOOOG M The largest amount of copper v/as found in portions of liver, heart and rib meat, only minute amounts being present .in the bony material. In this connection, it is stated that about two parts of copper have been observed in one million parts of human liver; ten parts in human kidneys, and as much as fifty parts 162 Bulletin 80 in sheep's liver. ^ Human food, however, is commonly contam- inated with copper compounds, which account for its presence in the human body. In brief, the observations detailed above have shown the suc- cessive positions of copper in the original ores of the Clifton- Morenci district; in the tailings wastes from these ores, in sus- pension and in solution in river waters exposed to milling operations ; in soils irrigated with these waters ; in the ground waters beneath these soils ; in vegetation growing upon them ; and even in the animal life of the region. It is of interest to ob- serve, first, the concentration through natural processes of small amounts of copper in the original rocks into the form of rich ores; and, second, the reversal, through human agencies, of this process, and the dilution of copper values till, in vegetation and in animal life, but traces of the metal can be detected. DISTRIBUTION OP COPPER IN PLANTS WITH ROOT SYSTEMS EXPOSED TO COPPER COMPOUNDS Corn Plants Grown in Soils Containing Copper In order to determine accurately the distribution of copper throughout a typical crop plant, thereby locating if possible the points at which injury may occur from copper compounds in the soil, three lots of corn plants were examined in detail. Two of these were grown (August 3 to November 13, 1907) in pots con- taining thirty-eight pounds of sandy loam soil very thoroughly mixed with 0.01 and 0.025 per cent of copper in the form of freshlj^ precipitated copper carbonate (Cu(OH)2.CuC03), made by mixing equivalent amounts of copper sulphate and sodium carbonate. The third was grown in soil containing 0.05 per cent of copper in the form of finely pulverized chalcocite. The samples were harvested with care to prevent contamina- tion with copper dust ; the root portions being washed in copper- free water saturated with carbon dioxide until the washings contained no trace of copper. Determinations of copper, as 5 Blyth, Poisons, fourth edition, pp. 640-64L Distribution op Copper in Plants 163 usual, were made as shown under ''I\Iethods of Analysis" (see Appendix herewith). Following are the tabulated results: TABLE VIII Eleven Stalks of Corn Grown in Soil Containing No. Plant part 3869p Lower six nodes, 24 in. long 3869g Basal sheaths of leaves from lower six nodes 3869r Blades of leaves from lower six nodes 3869s Upper four-seven nodes, 24 in. long 3869< Basal sheaths of leaves from upper nodes 3869U Blades of leaves from upper nodes 3869y Eudimentary ears 3869 Whole top portions 3868 Boots Containing 0.01 PER CENT ^3 (1907) Weight of sample, grams 43.4 Cu found, grams .00012 Cu p. p.m. 3.00 23.2 .0001 4.00 33.1 .00029 9.00 24.2 .00017 7.00 20.6 .00013 6.00 19.6 .00024 12.00 11.8 .0001 9.00 175.9 .00115 6.50 10.6 .00161 152.00 TABLE IX ■ Ten Stalks of Corn Grown in Soil Containing 0.025 Per Cent Copper as Cu(0H),.CxjC03 (1907) No. Plant part 3865a Five lower nodes, 14.4 in. long 3865?> Basal 12 in. of leaves and sheaths from five lower nodes 38650 Terminal 14 in. of leaves from five lower nodes 3865d Upper five-seven nodes, 14 in. long, including tassels and ears 3865e Leaves from same 3865 Whole top portions, 3866 Roots Weight of sample, grams 17 Cu found, grams .00024 Cu p. p.m. 14.00 17.2 .00037 22.00 14.4 .00047 33.00 9.2 .00017 19.00 19.2 .00035 18.00 77 .0016 21 9.2 .0067 728 164 Bulletin 80 TABLE X Four Stalks of Corn Grown in Soil Containing 0.05 Per Cent Copper as Cu,S. (1908) No. 3968p 0 Plant part Lower six nodes Weight f sample. grams 11.5 Cu found, grams .00010 Cu p.p.m. 9.00 3968q Basal sheaths from lower six nodes 7.5 .00008 11.00 3968r Blades from do. 15.7 .00021 13.00 3968s Upper five-six nodes 3.5 .00004 11.00 3968t Basal sheaths from upper five-six nodes 5.2 .00007 13.00 3968m Blades from do. 4.9 .00010 20.00 3968y Rudimentary ears Whole top portions 3.4 .00005 15.00 51.7 .00065 12.50 3978a Fine roots 3.23 .00081 251.00 3978fe Coarse roots 2.91 .00024 83.00 whole root system 6.14 .00105 171.00 In all of the corn samples shown above, the copper content of root systems is very much greater than that in the top por- tions of the plants, amounting to twenty-three times, thirty-four times, and thirteen times as much, respectively. In the aerial parts of all samples copper increases slightly but uniformly to- wards the upper and outer portions of the plants. This must be an effect. of transpiration, by which copper in solution is carried to the terminal portions of the plant and there deposited. The fine roots of one sample were found to contain about three times as much copper as the coarse roots — a fact which can be explained by the greater proportion of absorbing surface to weight in small roots. With reference to toxic effects, the culture in 0.01 per cent copper carbonate showed only a faint yellow striping of leaves, with no checking of growth. The 0.025 per cent culture gave leaves which were strongly striped with yellow, and the total growth reduced to less than one-half. Toxic effects evident in the top portions of this culture are manifestly to be associated mainly with the greatly increased copper content of its roots, since total amounts of copper in the top portions remain small. The 0.05 per cent culture of copper in the form of Cu=S, or finely powdered chalcocite, showed only faint toxic effects in the tops. The fol- lowing summary indicates the relation between toxic effects and copper content of materials. Distribution of Copper in Plants 165 Cu Cu in tops in roots Culture Condition p.p.m. p. p.m. Ratio Copper carbonate, 0.01% Cu Leaves faintly striped (precipitated) normal weight 6.50 152.00 1:23 Copper carbonate, 0.025% Cu Leaves strongly striped (precipitated) three-fourths yellow, half weight 21.00 728.00 1:34 Copper sulphide, 0.05% Cu Faintly striped leaves, normal weight 12.50 171.00 1:13 In tliis table a general relation is shown between the toxic effects in the aerial portions of the plant, and the amounts of copper in root systems ; but as to the soils employed toxic effects are influenced both by amounts and character of copper com- pounds present, as is shown further on following pages. In view of the fact that the small increase of copper in the carbonate cultures, from 0.01 to 0.025 per cent, caused severe toxic effects attended by an increase of copper in root systems from 152 to 728 p.p.m. of dry matter, it seemed desirable to in- vestigate thoroughly the quantitative relations between the copper in roots and the toxic effects as shown in vegetative growth. It was expected in this way to find a means of determining whether a plant contained an injurious or killing dose of copper, just as, analogously, killing doses of poisons in animals may be ascer- tained. With this end in view cultures of corn, beans, and squashes were grown in water, in pots of soil and in garden plots; and roots and top portions were examined quantitatively for copper. In preparing samples of roots for analysis, washing with 4 per cent hydrochloric acid was carried out with water cultures, but most of the samples were prepared by washing with large quantities of copper-free water saturated with carbon dioxide, until tlie washings showed no trace of copper. By still a third method the soil adhering to a sample was analyzed for copper, the ash was then determined and assumed to be soil, and a cor- responding amount of copper subtracted from the total found. For details see "Methods of Analysis." All of these methods undoubtedly give conservative figures for copper in root systems inasmuch as solvents not only remove externally adhering com- pounds but may also gradually act upon the copper content of 166 Bulletin 80 root systems. The acid-wash and soil-correction methods give severely minimum results. The carbon dioxide wash used in the majority of analyses is laborious but more satisfactory. Water Cultures (1907) Cultures of corn, beans, and squash were grown in University of Arizona well-water containing 250 p. p.m. of soluble solids. From 0.03 to 3.0 parts of copper as precipitated carbonate dis- solved in carbon dioxide were used in making cultures and the resulting growths of tops and roots were divided into the worst- poisoned and least-poisoned portions, for determinations of copper. Fig. 3. — Corn cultures, series 121-62, grown in University of Arizona well water, containing from .03 to 3. parts per million of copper as basic carbonate (Cu(0H),.CuC03). Series Com 121-62. — Grown in well water containing Cu as Cu(OH).,.CuCO, as follows: check, 3.0, 1.0, 0.8, 0.5, 0.3, 0.1, 0.08, 0.05', and 0.03 p.p.m. Cu. December 1-February 27, 1907. Series divided into two portions: a. Plants not badly poisoned ; roots growing ; tops showing Cu effects; 0.1, 0.08, o'.05, 0.03 cultures. (Nos. 3694, 3693.) 6. Plants badly poisoned; root growth arrested; tops living; 3.0, 1.0, 0.8, 0.5, and 0.3 cultures. (Nos. 3692, 3691.) Series Beans 121-66. — Grown in well water containing Cu as Cu(0H)o.CuC03 as follows: check, 3.0, 1.0, 0.8, 0.5, 0.3, 0.1, 0.08, 0.05, 0.03 p.p.m. Cu. December 9-February 27, 1907. Series divided into two portions : a. Least poisoned plants ; roots nearly normal, tops normal ; 0.3, 0.1, 0.08, 0.05, 0.03 cultures. (Nos. 3702, 3697.) Distribution of Copper in Plants 167 b. Worst poisoned plants; roots badly affected, tops less af- fected; 3.0, 1.0, 0.8, and 0.5 cultures. (Nos. 3700, 3699.) Series Squash 121-66. — Grown in well water containing Cu as Cu(0H)..CuC03 as follows: check, 3.0, 1.0, 0.8, 0.5, 0.3, 0.1, 0.08, 0.05, and 0.03 p.p.m. Cu. December 10-February 27, 1907. Series divided into two portions : a. Least poisoned plants; roots growing; tops strong; 0.3, 0.1, 0.08, 0.05, and 0.03 cultures. (Nos. 3698, 3701.) h. Worst poisoned plants; roots dead or nearly so; tops badlv affected; 3.0, 1.0, 0.8, and 0.5 cultures. (Nos. 3696, 3695.) TABLE XI Copper Content op Plants in Water Cultures Dry Cu matter Cu p.p.m. dry matter Condition of in found, . ^- ^ No. Series sample grams grams tops roots 3694 Corn, .1, .08, .05, .03 Tops affected G.3 .00009 14..30 3693 Corn, .1, .08, .05, .03 Eoots growing 2.3 .000236 102.60 3692 Corn, 3., 1., .8, .5, .3 Tops living 4.8 .000056 11.70 3691 Corn, 3., 1., .8, .5, .3 Roots arrested 2.8 .000572 204.30 3702 Beans, .3, .1, .08, .05, .03 Tops normal 9.4 .000198 21.10 3701 Beans, .3, .1, .08, .05, .03 Roots growing 2.6 .000157 60.40 3700 Beans, 3., 1., .8, .5 Tops affected 6.6 .000204 30.90 3699 Beans, 3., 1., .8, .5 Roots badly affected 1.6 .000494 308.80 3698 Squash, .3, .1, .08, .05, .03 Tops strong 10.4 .000333 32.00 3697 Squash, .3, .1, .08, .05, .03 Roots nearly normal .6 .000087 145.00 3696 Squash, 3., 1., .8, .5 Tops badly affected 3.6 .000092 26.00 3695 Squash, 3., 1., .8, .5 Roots dead .2 .000058 290.00 It is noteworthy, in this series, that the amounts of copper found in roots that still retain the power of growth average about 103 parts in one million of dry matter, as compared with 268 parts in dead roots whose protoplasm is presumably killed as an effect of copper. Badly poisoned roots in every instance show a great excess of copper over those less affected. The tops, on the other hand, do not show copper in proportion to the amounts in the roots, averaging the same amount of coi)per in badly poisoned (22.9 p.p.m.) and in slightly poisoned (22.5 p.p.m.) plants. Corn was observed to be distinctly more sensitive to copper in water culture than either squash or beans, as was 168 Bulletin 80 shown by the method of measuring growth of root tips marked with India ink, and noting points at which growth was retarded (R) and arrested (A). TABLE XII Showing Points at which Roots were Retarded or Arrested in Growth Cultures in Cu, in well water, parts per million 03 .05 .08 .1 .3 .5 .8 1. 3. Corn R A Beans R A Squash R A Photographs of the three series also indicate an earlier re- tardation of corn root development than of bean or squash root development; and show additionally that the top portions of cultures are not damaged in proportion to the root systems. TOXICITY OF COPPER SOLUTIONS TO PLANT ROOTS IN WATER CULTURE In order to gain some indication of effects in water culture of copper salts upon plants, several series of plants were grown under varying conditions, and effects observed of the kind of copper salts employed, strength of solution used, the kind of plant, and the effects of other salts present. Solutions were made in water free from copper, twice dis- tilled ; or, where permissible. University of Arizona well water, copper-free. The series Avere arranged, usually, to carry 0.01, 0.03, 0.05, 0.08, 0.1, 0.3, 0.5, 0.8, 1.0, 3.0, and 5.0 parts copper per million of water. The cultures were made in 600-c.c. bottles, covered with pasteboard squares saturated with hot paraffin and perforated M'ith three holes for plant seedlings held in place by cotton. Effects upon cultures were judged by elongation of roots de- termined by the usual method of marking with India ink 5 mm. back of root tips and noting growth after twenty-four liours. Corn, beans, and squash were the plants employed and the points Toxicity of Copper to Plant Roots 169 particularly noted were those at which growth was retarded and at which it was arrested. Table XIII gives the data condensed from the experimental records : TABLE XIII (a) Toxic Effects op Copper upon Boots of Water Cultures First experiment (1905) Cu in solution Culture Beaus Copper salt employed CliSO, Kind of water Distilled Growth 1 l)etween etarded Growth arrested p. p.m. between, p. p.m. .25—1.25 Beans Cu(OH),.CuCO, Well .57—5.7 Cantaloupes CuSO, Distilled less than .25 Cantaloupes Cu(OH),.CuCO, Well .57—5.7 Indicating lessened toxicity in well water. ^^''C^fh-T T^ rt rr> Fig. 4. — Bean cultures (eighth exp.), showing effects of varying con- centrations of copper in distilled water and in solutions of mixed salts. S. salt solutions; D, distilled water; W, no copper, and .05 to 3. parts per million of copper. TABLE XIII (b) Eighth experiment (1905) Corn Cu(0H),.CuC03 Salt solution* .3 — .5 .8 — 1. Corn Cu(OH),.CuCO., Distilled less than .01 .1 — .3 Beans Cu(OH),.CuCO, Salt solution* .1 — .5 .8 — 1. Beans Cu(OH),.CuCO,, Distilled .1 — .3 .5 — .8 Squash Cu(0H),.CuC03 Salt solution* .1 — .5 .8 — 1. Squash Cu(OH),.CuCO,, Distilled .1 — .3 .3 — 5 Showing lessened toxicity in salt solution. * NaCl 64 pts. Na,SO, o CaS04 7.3 Univ. ^\ ell water salts 26.1 Total 100 pts. per 100,000. 170 Bulletin 80 TABLE XIII (c) Fifth experiment (1905) Corn CuSO, Distilled .01— .05 .1 — .5 Corn Cu(0H),.CuC03 Distilled .01— .05 .1 — .5 Indicating equal toxicity of Cu as sulphate and as carbonate, and (com- pare second, fourth and eighth experiments) great toxicity to corn in distilled water. TABLE XIII (d) Third experiment (1905). Beans CuSO^ Distilled .1 — .3 Beans Cu(0H)o.CuC03 Distilled .1 — .3 Toxicity to beans of Cu as sulphate and as carbonate was the same. TABLE XIII (e) Seventh experiment (1905) Squash CUSO4 Distilled .01— .05 .1 — .5 Squash Cu(OH)2.CuC03 Distilled .01— .05 .1 — .5 Toxicity to squash of Cu as sulphate and as carbonate was the same. TABLE XIII (f) Second experiment (1905) Cu in solution . A . Copper salt Kind of Growth retarded Growth arrested Culture employed water between, p. p.m. between, p. p.m. Corn Cu(0H),.CuC03 Well .1 — .3 .8 —1. Beans Cu(OH),.CuCO, Well .1 — .3 .8 —1. Toxicity of copper as Cu(OH)2.CuC03 to corn and beans was the same. TABLE XIII (g) Fourth experiment (1905) Corn Cu(0H),.CuC03 Well .05— .08 .8 —1. Squash Cu(0H),.CuC03 Well .1 — .3 .8 —1. Corn was somewhat more sensitive to copper as Cu(0H)2.CuC03 than squash. TABLE XIII (70 Sixth experiment (1905) Beans Cu(0H),.CuC03 Well .1 — .3 1. —3. Squash Cu(0H),.CuC03 Well .1 — .3 .8 —1. Beans and squash Avere about equally sensitive to copper as Cu(0H)2.- CUCO3 These experiments, which are not stated in complete detail here, indicate quite clearly : 1. That the toxic effects of copper are less in the presence of the salts ordinarily contained in well waters than in distilled- Toxicity of Copper to Plant Roots 171 water solution. This fact indicates that the toxicity of copper salts in the presence of soil-water solutions is probably miniinized. In all cases it was observed that root growth was much more vigorous in salty than in distilled water, where no copper was used. Lessened toxicity of copper in salty solutions may there- fore in part be due to greater vigor and resistant qualities of plant cells grown in such solutions. 2. Copper appears to be equally toxic as sulphate or as basic carbonate. 3. Corn is probably more sensitive to copper salts than is squash or beans. Stimulation Effects in Water Cultures In view of the debated question as to stimulation of plant growth by minute amounts of copper salts, it is of interest to observe that, quite consistently, the most vigorous root growth is associated with concentrations of from 0.01 to 0.1 parts per million of copper, as shown by details from cultures described on previous pages. TABLE XIV (a) Stimulation Effects of Copper upon Eoots of Plants in Water Cultures Corn roots grown in well water with Cu(OH)2.CuC03 Condition Tops of plants showing increased growth at .08 and .1 p.p.m. Showing stimulation at .01 p.p.m. TABLE XIV (h) Bean roots grown in well water with Cu(OH)2.CuC03 Condition Tops of plants in .08 and .1 cultures higher than in .05, .03, .01, and check. \^ ijl 11 1 Lf\J (O gXV^VVil ilA V»V,Ai Cu p.p.m. Elongation 48 hrs. check 23.4 mm. .01 27.3 .03 17.6 .05 17.3 .08 19.4 .1 18. .5 J^Il^Hll 1 l/U •lO giv J \^ H ± IL >> V. il Cu p.p.m. Elongation 48 hrs check 2.5 mm. .01 2.2 .03 4.7 .05 2.8 .08 2.5 .1 2.9 Showing stimulation at .03 p.p.m. 172 Bulletin 80 TABLE XIV (c) Corn roots grown iu well water with Cu(OH)2.CuC03 Cu p. p.m. Elongation 48 hrs. Condition check 14.2 mm. vigorous .03 17.3 most vigorous .05 14.4 most vigorous .08 9.6 retarded .1 10.3 retarded Showing stimulation at .03 p.p.ju. TABLE XI A^ (d) Squash roots grown in well water with Cu(0H)...CuC03 Cu p.p.m. Elongation 48 hrs. Cu p.p.m Elongation 48 hrs. cheek 12.0 mm. .08 12.3 .03 10.7 .1 13.2 .05 10.0 Showing no stimulation at these concentrations. TABLE XIV (e) Bean roots grown in well water with Cu(0H)2.CuC0;; Cu p.p.m. Eloi igation 48 hrs. Condition check 2.4 mm. Tops strong through- .03 3.1 out, showing stimula- .05 4.5 tion at .03, .05, and .1 .08 2.8 .1 3. Showing stimulation at .05 p.p.m. TABLE XIV if) Squash roots grown in well water with Cu(0H).j.CuC03 Cu p.p.m. Elongation 48 hrs. Cu p.p.m. Elongation 48 hrs. check 13.1 mm. .08 7.6 mm. .03 7.4 .1 9.7 .05 8.8 .3 3.7 Not showing stimulation consistently. TABLE XIV (g) Corn roots grown in well water with Cu(OH)2.CuC03 Cu p.p.m. Elongation 48 hrs. Cu p.p.m. Elongation 48 hrs. check 9.8 mm. .1 13.5 mm, .01 13.8 .3 10. .05 17.5 .5 3.8 Showing strong stimulation .01 to .1 mm. Toxicity of Copper to Plant Roots 173 TABLE XIV (70 Corn roots grown iu distilled water with Cu(0H)o.CuC03 Cu p p m. Elongation 48 hrs. Cu p.p.m. Elongation 48 hrs. Check 27.6 mm. .05 5.7 mm. .01 1.8 -1 ^-^ No stimulatiou; eccentric results. TABLE XIV (i) Beau roots grown in well water with Cu(OH)2.CuC03 Cu p p m Elongation 48 hrs. Cu p.p.m. Elongation 48 hrs. u 1 '7 ,i,,i, 1 6. mm. check -2. nim. ->• .05 6. -5 -8 Showing stimulation at .05 to .1 p.p.m. TABLE XIV (,;■) Bean roots grown in distilled water with Cu(0H)o.CuC03 Cu p p m Elongation 48 hrs. Cu p.p.m. Elongation 48 hrs. che'^k 3. mm. .1 3.1mm. .01 3. .3 1-6 .05 3.7 Showing no stimulation. TABLE XIV (Ic) Squash roots grown in well water with Cu(0H)o.CuC03 Cu p p m. Elongation 48 hrs. Cu p.p.m. Elongation 48 hrs. Check 2.4 mm. .1 5.7 mm. .05 4.9 .5 -4 Showing stimulation at .05 to .1 p.p.m. TABLE XIV (0 Squash roots grown in distilled water with Cu(0H)..CuC03 Cu p p m. Elongation 48 hrs. ' Cu p.p.m. Elongation 48 hrs. eheck 3.3 mm. .05 3.1mm. .01 3.3 .1 2.1 Showing no stimulation. TABLE XIV (m) Bean roots grown in distilled water with CuSO^ Cu p p.m. Elongation 48 hrs. Height of tops 1 2.9 mm. 87 mm. '.3 1.2 91 .5 .6 85 Bean roots grown in distilled water with Cu(0H),.CuC03 Cu p p.m. Elongation 48 hrs. Height of tops 1 2.9 mm. 98 mm. ".3 1. 88 .5 .6 84 Showing same behavior with CuSOi and Cu(0H)o.CuC03. 174 Bulletin 80 TABLE XIV («) Squash roots grown in distilled water with CUSO4 Cu p. p.m. check .01 Elongation 24 hrs. 3.6 mm. 2.8 Cu p.p.m. .05 .1 Elongation 24 hr.s. 1.4 mm. 2. Squash roots grown in distilled water with Cu(0H)2.CuC0; Cu p.p.m. Elongation 24 hrs. Cu p.p.m. check 3.6 mm. .05 .01 3.8 .1 Elongation 24 hrs. 3.6 mm. 3.8 Doubtful stimulation at .01 p.p.m. Elongation 24 hrs. 1.1 mm. .4 TABLE XIV (o) Com roots grown in distilled water with CUSO4 Cu p.p.m. Elongation 48 hrs. Cu p.p.m. check 8.7 mm. .05 .01 10.9 .1 Elongation 48 hrs. 4.7 mm. 1.5 Corn roots grown in distilled water with Cu(0H)2.CuC0 Cu p.p.m. Elongation 48 hrs. Cu p.p.m. check 8.7 mm. .05 .01 13.2 ,1 Elongation 48 hrs. 3.3 mm. 2. These cultures, while somewhat fragmentary, afford excellent indications of stimulating effects upon plant roots. Excluding squash, which is not satisfactory material to work with, corn and beans show consistent stimulations at very high dilutions. Meas- urements in all cases are averages of about ten observations. TABLE XV SUMMAKY OF STIMULATION EFFECTS Character and strength in copper of solution producing stimulation Experi- ment Culture Copper salt used A Well water' Distilled water a Corn roots Cu(OH)2.CuC03 at .01 p.p.m. b Bean roots Cu(OH)2.CuC03 .03 c Corn roots Cu(0H),.CuC03 .03 e Bean roots Cu(0H),.CuC03 .05 g Corn roots Cn(0H),.CuC03 .Ol-.l h Corn roots Cu(0H)..CuC03 none at .01 or above i Bean roots Cu(0H)..CuC03 .0.5-. 1 3 Bean roots Cu(0H)..CuC03 none at .01 or above 0 Corn roots C11SO4 .01 0 Corn roots Cu(0H),,.CuC03 .01 Effects of Soil upon Toxicity 175 Only at very high dilutions (one part of copper to from 10,000,000 to 100,000,000 of water) are accelerations of root growth observed. These occur with both corn and beans, in well water. In distilled water stimulation was observed only at the highest dilution — 1 :100.000,000. In well water stimulation was observed at from 1:100,000,000 to 1 : 10,000,000— consistently with the well known fact that in presence of other soluble salts the effects of copper are lessened. EFFECTS OF SOIL UPON TOXICITY OF COPPER SOLUTIONS Of prime importance in connection with possible toxic effects of copper in soils are the various reactions (1) converting in- soluble into soluble compounds, (2) reconverting these again into insoluble combinations, and (3) modifying the toxic effects of copper salts in solution. As shown in the table of solubilities, both basic carbonate of copper and chrysocolla are soluble in carbon dioxide, forming solutions which in water cultures are highly toxic in character. Sulphides of copper are first oxidized to the sulphate, which is easily soluble : Cu^S + 50 = CuSO, + CuO For instance, 100 grams of chalcocite ore containing 3.2 per cent copper were shaken in a flask with 600 c.c. of water, frequently, during twenty-eight days. At the end of that time 500 c.c. of solution contained 0.0132 grams of copper. Copper sulphate then reacts in the soil to form various insoluble compounds with consequent lessening of toxic action. With calcium carbonate the following represents a reaction which may occur : 2 CuSO, + 2 CaCOg + H,0 = Cu(OH),.CuCOp, + 2 CaSO, + CO^ For instance, two grams of precipitated carbonate of lime were added to an excess of ten grams of copper sulphate in one liter 6 "University of Arizona well water" contains 250 p.p.m. of soluble solids, mainly sodium sulphate. 176 Bulletin 80 of water, and digested with frequent shaking for over four months, the green precipitate being then filtered off, dried and analyzed for copper : Weight of precipitate taken 100.00 mg. Cu found 47.85 Theoretical Cu in basic carbonate 57.38 Indicating by the formula above a conversion to basic carbonate of copper of over 83 per cent of the solid carbonate of lime pres- ent. Bicarbonate of lime in solution also reacts with copper sulphate to form the basic carbonate' CaH.lCO,), + 4 CuS0,.5 HoO = 2 Cu(OH)2.CuC03 + CaSO^ + 3 H0SO4 + 16 H3O 3 CaH, ( CO3 ) 2 + 3 H,SO, = 3 CaSO, -f 6 HoO + 6 CO^ The silicates of the soil, also, and particularly those of zeolitic character, react readily with soluble copper compounds to form insoluble copper silicates. Organic matter likewise combines with large amounts of copper, to form compounds of indefinite or unknown composition. As a result of all these reactions, when soils are shaken up with solutions of copper salts the latter are withdrawn from solution in large amount. Under irrigation con- ditions, where waters containing minute amounts of copper are filtered through relatively large masses of soil, this action is nearly or quite complete. Five large percolators were arranged with varying depths of TABLE XVI Percolation op Copper Solutions Through Soils Depth Solution used A Amount of percolate, c.c. Soil r "4 Cu in solution, Cu compound p. p.m. Copper in percolate, p.p.m. Sandy loam lin. Cu(OH)2.CuC03 in CO, water 95 2000 none Sandy loam 5 in. Cu(0H)o.CuC03 in CO, water 95 1500 none Sandy loam 9 in. Cu(OH)2.CuC03 in CO, water 95 2000 none Sandy loam lin. Cu(0H)2.CuC03 in CO, water 56 2000 .85 Heavy clay containing .003% Cu 12 in. Cu(0H),.CuC03 in CO2 water 8.5 600 Heavy clay containing .003% Cu 12 in. CUSO4.5 HjO 254 150 7.3 Effects of Soil upon Toxicity 177 soil resting on filter paper supported by a perforated porcelain plate. Two soils, heavy clay and sandy loam, were employed; and two copper solutions, sulphate and bicarbonate. In nearly all cases copper as basic carbonate was entirely removed from solution in percolating through as little as a single inch of sandy loam. Although appreciable amounts of copper sulphate passed out of a soil, the latter in that case itself contained a very small percentage of copper. Inasmuch as soluble copper in irrigating waters must be present ordinarily as basic carbonate, its complete withdrawal by thin layers of soil is significant in connection with irrigated crops. Irrigation Experiments A set of cultures was arranged to test the effects upon crop plants of solutions of basic copper carbonate so applied as to filter through the soil before reaching the plant roots. Six-inch Fig. 5. — Diagram of pot culture irrigated through two-inch pot inside. flower-pots were filled with sandy loam soil. In the middle of each of these pots a two-inch pot was half buried, and the plants experimented with were grown in the circles of soil between the large and small pots. These plants were irrigated by pouring the solution used into the small pot, through the bottom of which it passed, necessarily filtering through more or less soil before 178 Bulletin 80 reaching the plant roots. Radishes, beans, cantaloupes, cucum- bers, lettuce, peas, beets, corn, berseera, avas, onions, barley, and wheat were employed; corn, barley, and wheat being especially successful under these conditions. All cultures were in pairs, one of each pair being irrigated with solutions of basic carbonate of copper in COo-water, and the check cultures with water only. In all other particulars — original strength of plants, exposure to light and air, and amount and time of watering — the con- ditions were identical. These cultures were carried on in a greenhouse set aside for the purpose. The experiment was begun in November and ended the following March. The solutions of basic carbonate of copper employed contained from 0 to 55 p. p.m. of copper, averaging about 20 parts, which is from 7 to 670 times as much as has been observed in the waters of the Gila River from time to time. TABLE XVII Condition at Maturity of Cultures Irrigated with • Copper Solutions, AS Compared avith THOSii Irrigated with Water C, copper culture; W, check. Tops C and W. Radishes Beans C greener Lettuce Peas Beets Corn Stimulated? C showing stronger Berseem C stimulated, earlier bloom same m appear- ance and weight C and W. About the same C and W. About the same C and W. Aver- aging the same Weighing the same, but C ap- pearing stronger C more advanced in growth, but not so heavy- Roots The The same, but in C roots were removed h in. from inner pot hole Equal; same number of nodules; very local ef- fect of Cu at pot hole The same except that in C roots were dead i x 3 in. under pot hole Both C and W having abundant nodules. No apparent damage by Cu Fewer in soil under pot hole in C, otherwise equal Equally developed, both showing strong nodule development. Effects of Soil upon Toxicity 179 Avas Onions Barley Wheat Tops C and W. Same apparent growth C and W. Same general appearance C stimulated, ma- The same in tured over twice weight, but C as much grain matured more grain C stimulated Identical appear- matured 20% ance, but C ma- more grain tured more grain Roots In C roots within i in. of pot hole damaged. Both C and W show strong nodule develop- ment Very little local effect of Cu just under inner pot hole in C No roots in C for space of 1 X 3 in. under inner pot hole In C no roots under in- ner pot hole for space of li X 4 in. In practically all cases a distinct but very local effect of copper solutions upon plant roots under the inner pot hole was observed. For a distance of a half-inch or less from the small pot hole exposed roots were dead or missing. The soil in this area was observed in two instances to contain 0.25 and 0.45 per cent copper, respectively. In one instance 80 per cent of the copper added was found in the 43 grams of soil just under the bottom of the little pot, showing the rapidity with which copper is removed from its solutions by filtration through the soil. The tops of the cultures under consideration in no instance showed injury, but in certain cases were in a distinctly advanced condition. The amounts of copper contained in material derived from these cultures are as follows : TABLE XVII (a) Copper Content of Plants Irrigated with Copper Solutions >r.v matter, Cu P. p.m. of Cu in dry grams grants material Sample No. 3673 Wheat and barley tops grown in check 3675 soil containing a trace (.002.5 per cent) of copper 32.90 .000100 3.04 3672 Tops of beans, peas, corn, lettuce, car- rots, cucumbers and avas grown in check soil 133.00 .000350 2.60 180 Bulletin 80 Sample No. 3674 3676 3690 Dry matter, grams Tops of wheat and barley irrigated with water averaging 20 p.p.m. cop- per 30.70 Tops of beans, berseem, peas, onions, lettuce, beets, radishes, corn, avas, ■ barley, and wheat irrigated with water averaging 20 p.p.m. copjjer .... Eoots of same (washed in 4 per cent HCl) Cu grams P.p.m. of Cu in dry material .000400 13.00 27.20 .000751 27.60 8.30 .0007.50 90.00 In brief, even when relatively large amounts of water contain- ing excessive quantities of soluble copper were applied and the experiments so arranged that all of the copper remained in the limited volumes of soil employed, no general injury to the plants was observed, although apparently slight stimulation occurred in some cases. Prolonged irrigation with such solutions M^ould be required to saturate the soil to a depth sufficient to seriously injure plants grown in it. ^ / aV 1 A I'; \ ■V' ^ij i^) ■.-!!.' ^ '' Fig. 6. — Wlieat and barley irrigated (C) with copper solutions filtered through soil, and (W) with Avell water. Both show stimulated growth with copper. Cultural Experiments 181 CULTURAL EXPERIMENTS Pot Cultures with Treated Soils Pot cultures of corn, beans, and squash were also grown in soils containing copper in the form of precipitated carbonate (Cu(OH)2.CuC03), finely powdered (100-mesli) chalcocite or sulphide ore, and finely powdered chrysocolla or silicate ore. Large glazed stone jars containing thirty-eight pounds of soil were used. Effects on growth were observed and the copper content of tops and of root systems was determined. The follow- ing tabulations relate to the work done in this direction, the state- ment showing the copper content of corn, bean, and squash plants expressed in parts per million of copper in dry matter. TABLE XVIII Copper Carbonate Series (1908 ), Beans Sample No. Culture Cu in soil, per cent Appearance and height of plants Dry matter, grams Cu found, r grams Cu p. p.m. in tops roots Normal 3944 Beans Cheeks- 39 in. 16.6 .00022 13 4013 Beans Check* .72 .00033 453 3945 Beans .01 38 17.2 .00027 16 4014 Beans .01 1.35 .00116 859 3946 Beans .025 39 15.9 .00033 21 4015 Beans .025 1.21 .00115 950 Toxic effects begin at about .035% Cu in soil • Stunted 3947 Beans .05 30 13.2 .00031 23 4016 Beans .05 1.09 .00148 1358 3948 Beans .1 25 6.7 .00011 16 4017 Beans .1 1.44 .00212 1472 3949 Beans .25 14 3.7 .00009 25 4018 Beans .25 1.35 .00243 1800 3950 Beans .5 15 2.9 .0001 35 4019 Beans .87 .00147 1690 3951 Beans 1. 12 2.2 .00009 41 4020 Beans 1. .53 .00106 2000 3952 Beans 1.5 14 2.1 .00009 44 4021 Beans 1.5 .5 .00115 2300 Containing traces of copper, .0025%. 182 Btjlletin 80 Fig. 7. — Bean cultures grown in soils containing copper as precipitated carbonate, from none to 1.5 per cent Cu. TABLE XIX Copper Carbonate Series (1907), Corn Sample No. 3870 Culture Corn Cu in soil. per cent Check* Drv matter, grams 41.2 Cu found, grams .00020 Cu p. tops 4.40 388.1 Corn Cheek* 8.8 .00035 3869 Corn .01 175.9 .00115 6.50 3868 Corn .01 10.6 .00161 3865 Corn .025 77.0 .00160 21.00 3866 Corn .025 9.2 .00670 3864 Corn .05 47.7 .00103 22.00 3867 Corn .05 4.4 .00328 3863 Corn .10 26.8 .00079 30.00 3862 Corn .15 9.8 .00046 47.00 3861 Corn .20 14.4 .00073 51.00 3860 Corn .30 4.6 .00110 239.00 roots 40.00 152.00 728.00 745.00 Containing traces of copper, .0025%. Fig. 8. — Corn cultures grown in soils containing copper as precipitated car- bonate, from none to .2 per cent Cu. Cultural Experiments 183 Copper Carbonate Series (1908), Corn Sample No. Culture Cu in soil, per cent Appear- ance and height of plants Normal Dry matter, grams Cu found, grams Cu p. p.m. roots 3992 Corn Check* 43 in. 7.48 .00058 78.00 3993 Corn .01 41 2.35 .00049 209.00 3994 Corn .015 35 4.07 .00171 420.00 3995 Corn .02 41 5.31 .00397 748.00 Toxic effects begin at about .023% Cu in soil Stunted 3996 Corn .025 33 in. 4.81 .00245 509.00 3997 Corn .05 15 .31 .00023 742.00 3998 Corn .10 22 3.62 .00651 1798.00 4000 Corn .20 20 1.99 .00444 2231.00 * Containing traces of copper, .0025%. Copper Carbonate Series (1908), Squash Sample No. Culture Appear- Cu ance and Dry in soil, height matter, per cent of plants grams Cu found, grams Cu p.p A m. in tops roots Normal 3937 Squash Check* 16 in. 11.2 .00016 14.00 3938 Squash .01 16 6.3 .00023 36.00 3939 Squasli .025 15 9.2 .00031 39.00 • 4026 Squash Chk., .01, and .025 .24 .00004 169.00 Toxic effects begin at about .035% Cu in Blanched and stunted soil. 3940 Squash .05 11 in. 3.7 .00017 46.00 3941 Squash .10 11 2.3 .00014 61.00 Fig. 9. — Corn cultures grown in soils containing copper as sulphide (chalco- cite), from none to 1. per cent Cu. 184 Bulletin 80 TABLE XX Chalcocite Series ( :i908) Sample No. Culture Cu in soil, per cent Appear- ance and height of plants Dry matter, grams Cu found, grams Cu p. p.m. in A tOJJS roots Normal 3979 Corn Check * 36 in. 17.60 .00026 15.00 3979f Corn Cheek^ fr 4.62 .00027 58.00 3980 Corn .01 33 11.60 .00011 10.00 3980e Corn .01 2.94 .00023 78.00 3981 Corn .02 38 19.40 .00021 11.00 3981c Corn .02 6.14 .00114 186.00 3982 Corn .03 35 17.90 .00028 16.00 3982c Corn .03 6.99 .00176 252.00 3968 Corn .05 45 51.70 .00065 13.00 3978 Corn .05 6.14 .00105 171.00 Toxic effects begin at about .08% Cu in soil. Stunted 3983 Corn .10 36 in. 14.00 .00031 22.00 3983c Corn .10 yellow 6.08 .00625 1028.00 3984 Corn .50 8 in. 3.20 .00040 125.00 3984c Corn .50 .47 .00065 1383.00 3985 Corn 1.00 12 3.20 .00050 159.00 3985c Corn 1.00 .49 .00089 1816.00 Containing traces of copper, .0025%. The cultures described in the foregoing tables indicate sev- eral interesting facts more or less applicable to field conditions. (1) Precipitated carbonate of copper is shown to have a much more toxic effect upon corn than the finely pulverized ores of chalcocite or chrysocolla. With the precipitated car- bonate 0.025 per cent in the soil was distinctly toxic, while with chalcocite and chrysocolla about 0.08 per cent was required to produce an equal effect. Inasmuch as all of these combinations of copper may occur in a soil subject to mining detritus, a mere determination of total copper in soils containing doubtfully toxic quantities cannot convey trustworthy information as to the in- juriousness of the amounts present. Moreover, since it has been shown that in the case of pre- cipitated carbonate, and sulphate of copper, equivalent quantities of these salts in solution are equally toxic, it is probable that the greater toxicity of the carbonate is due to its greater solubility under soil conditions. It is, in fact, shov/n in table I, ' ' Solubili- Cultural Experiments 18'5 TABLE XXI Chrysocolla Series (1908) Sample grams No. Appear- Cu ance and in soil, height per cent of plants Dry matter, grams Cu found. Culture Cu p.p.m . in r roots tops Normal 4003 Corn Check* 32 in. 25.60 .00025 10.00 4003c Corn Clieek* 6.46 .00012 19.00 4004 Corn .05 33 23.50 .00026 11.00 4004c Corn .05 6.70 .00062 93.00 Toxic effects begin at about .08% Cu in soil. Dwarfed 4005 Corn .10 30 in. 17.90 .00024 13.00 4005c Corn .10 striped 5.82 ' .00094 162.00 4006 Corn .10 28 in. 10.50 .00017 16.00 4006c Corn 1.00 yellow 4.29 .00233 543.00 * Containing traces of copper, . 0025%. Fig. 10. — Corn cultures grown in soils containing copper as silicate (chryso- colla), from none to 1. per cent Cu. ties of Copper Compounds," that precipitated copper carbonate is soluble to the extent of 1.5 parts in 1,000,000 of water, while copper sulphide is soluble to the extent of 0.09 parts of copper in 1,000,000 of water. It is most probable, also, that the finely divided condition of the precipitated carbonate is more favorable to solution, and also to reaction with the acids of plant roots. (2) Corn is seen to be distinctly more sensitive to the car- bonate of copper than either beans or squash. With corn, toxic effects appear with 0.02 per cent of copper in the soil, while with beans and squash these toxic effects do not appear until 0.035 per cent of copper in the soil is reached. As is suggested 186 Bulletin 80 in the following pages, the physical constitution of root systems may account in part for varying degrees of sensitiveness to cop- per compounds. The presence of copper in tops and roots of check is due to 0.0025 per cent of copper in the soil which was supposed orig- inally to be free from this element. Pot Cultures with Field Soils Two field soils containing copper from irrigating waters were tested in pot culture with reference to toxic effects and Fig. 11. — Pot cultures of corn in field soils coutaining tailiugs. No. 3887, .027% Cu; no. 3888, .047% Cu; and no copper. Cultures in field soils are slightly affected. copper content of root systems. The soils employed were from a field showing varying effects of accumulations of tailings, im- mediately southeast of Safford : Cu in soil, Sample per cent 3887 Sandy loam, surface 12 in. of soil recently put under irri- gation 0L( 3888 Heavy clay (tailings) mixed with sandy loam, surface 12 in., long under irrigation, much tailings 047 In these two soils, differing mainly through the addition of tailings to No. 3888, cultures of corn, beans, and squash were made, and examined for copper with the following results : CuLTi^RAL Experiments 187 TABLE XXII Cultures in Tailings Soils No. Pot culture Condition 3887 Corn in sandy loam Distinctly striped 3888 Corn in sandy loam Less distinctly and tailings striped 3887 Beans in sandy loam Normal appearance 3888 Beans in sandy loam Normal appearance and tailings 3887 Squash in sandy loam Yellow and stunted 3888 Squasli in sandy loam Normal appearance and tailings Cu in soil, per cent .027 .047 .027 .047 .027 .047 Cu p. p.m. in tops 28.00 19.00 73.00 45.00 roots 453.00 163.00 1523.00 703.00 Fig. 12. — Showing effects pf copper modified by tilth of soil. Strong growth, lumpy mixture; weak growth, thoroughly mixed. Bean cultures appeared little affected by copper iu either No. 3887 or No. 3888; but squash was distinctly damaged in No. 3887, being yellow and stunted. The leaves of both cultures of corn were paler than those of the check, but in soil No. 3887, containing less copper, the leaves of corn were more distinctly striped than in No. 3888. This is probably due to the sandy character of No. 3887 with consequently decreased adsorptive 'action upon copper salts. Lumpiness in the heavier soil might also account for a lessened toxic action, as indicated by an experiment in which 0.1 per cent of copper in the form of pre- 188 Bulletin 80 cipitated carbonate was mixed (1) intimately and (2) in lumpy condition. Results were as follows: Sample Cu as pptd. Cu p.p.m. No. carbonate, per cent Condition in roots 3998c 0.1 well mixed 22 in. high, much blanched 1798.00 3999c 0.1 lumpy 28 in. high, mostly green 457.00 In these instances it may be noted that toxic effects are asso- ciated with higher copper content of roots of plants, rather than with copper content of soils employed. As in other cultures it is observed that beans, though carry- ing a higher copper content than corn, show less toxic effects — a fact possibly to be explained by the higher protein content of the plant with a consequently greater capacity for absorption of copper before toxic effects appear. Pot and Plot Cultures In order to carry experimental cultures further towards field conditions, cultures of wheat and corn in small plots of sandy loam garden soil, 2i/> X 18 feet, were grown, copper in the form of finely powdered sulphate having been thoroughly spaded in four times to a depth of nine inches in the amounts showii in table XXIII. The roots of these cultures were harvested and examined as usual for copper. TABLE XXIII Corn Grown in Garden Plots Containing Cu Applied as CuSOi (1914) Sample No. Cu added, per cent Condition of leaves Dry matter, grams Cu found, grams Cu p.p.m. roots 5858a none Solid green 11.0 .00015 14.00* Toxi ic effects begin at about .008% Cu in soil. 5859a .01 Distinctly yellow striped 11.6 .00117 101.00 5860a .025 Distinctly yellow striped 8.6 .00211 246.00 5861 o .05 Distinctly yellow striped 7.3 .00215 296.00 5862a .10 Strongly yellow striped 4.3 .00300 698.00 5863a none 6.2 .00013 21.00* Probably resulting from roots spreading to copper soils. Cultural Experiments 189 TABLE XXIV Wheat Grown in Garden Plots Containing Cu as CuSO^ (1914) Sample No. Cu added, per cent 5648a none 5649a .01 Toxic effects 5650a .025 5651a .05 5652a Dry Condition matter, of leaves grams 29 in. high; good 4.46 29 in. high; good 3.16 begin at about .02% Cu in soil. 25-27 in. high; affected 3.23 23 in. high; severely af- 1.90 fected .10 20 in. high; very severely 1.33 affected Cu found, grams .00012 .00190 .00200 Cu p.p.m. in roots 27.00 601.00 .00260 805.00 .00380 1737.00 1504.00 TABLE XXV Wheat Grown in Pots to Check Plots Containing Cu as CuSOi (1914) Cu added, per cent 5672a .0025 Sample No. Condition of leaves Green; 27 in. high Toxic effects begin at about .005% Cu in soil 5673a 5674a 5675a 5676a .01 .025 .05 .10 Yellowish; 23 in. high Yellow and stunted; 17 in. high Yellow and stiinted; 12 in. high Yellow and stunted; 4-12 in. Dry matter, grams 1.51 Cu found, grams .00007 Cu p.p.m. in roots 46.00 1.96 .00035 179.00 .84 .00030 357.00 .52 .00031 593.00 .30 .00044 1476.00 high The corn series contains much smaller proportions of copper in the roots than either of the wheat series, a fact explained in part by the coarser roots of corn, which therefore have less ab- sorptive surface in proportion to their weight. Wheat roots grown in plots show much more copper than pot samples, although the copper is much more toxic to the plants in pots than in plots, a contradiction not easily understood unless it be that other less favorable conditions of growth in pots were responsible for the backward condition of the plants. Field Samples op Soils and Vegetation In order to relate, if possible, the experimental work detailed on previous pages to samples of field material, roots of barley, wheat, oats and corn, were collected in the district studied and the amounts of copper in them determined. The samples of bar- 190 Bulletin 80 TABLE XXVI Copper in Soils, and in Boots of Plants Grown in Field Soils Contain- ing Mining Detritus, near Solomonville and Saffokd (1914) Dry Cu Cu p.p.ni. iu matter, found, , -^ s Jan. 3, 1909 grams grams tops roots 4008a Barley tops selected for toxic effects from tailings soil (Wm. Gillespie), Solomonville, under Montezuma Canai 13.90 .00061 43.80 4008b Barley roots, ditto 2.70 .00160 592.50 4009rt Oat tops selected for toxic effects from field one mile west of Solo- monville, under Montezuma Canal 28.30 .00121 42.70 4009b Oat roots, ditto 2.55 .00025 . 98.00 Per cent Dry Cu Cu p. p.m. Cu in soils matter, found, , -^ v shaken March, 1914 grams grams yellow green from roots 5544a Barley roots, yellow plants.. 3.78 .00037 98 .017 5545a Barley roots, green plants.... 2.33 .00290 124 .006 5546a Barley roots, yellow plants .. 3.41 lost 5547a Barley roots, green plants.- 3.80 .00047 123 5548a Wheat roots, yellow plants .... 1.40 .00044 314 .054 5549a Wheat roots, green plants 1.25 .00048 382 .014 5550a Barley roots, less green plants 2.17 .00077 354 5551a Barley roots, stronger plants 3.34 .00110 329 5552a Oat roots, yellow plants 1.67 .00066 394 .050 5553a Oat roots, green plants 1.77 .00030 169 .039 5554a Barley roots, yellow plants .. 1.38 .00057 411 .073 5555a Barley roots, green plants .... 1.42 .00041 289 .032 Average 314 236 .048 .023 4010 Corn roots (1908) in tailings soil, Solomonville 16.12 .00097 60 November, 1914 5841a Corn roots, tailings 9 in. deep 10.18 .00021 21 5842a Corn roots, tailings 8 in. deep 11.08 .00038 34 5843a Corn roots, old tailings 10.01 .00038 38 .055 5844a Corn roots, tailings 6-12 in. deep 21.48 .00039 18 5845a Corn roots, old tailings 16.24 .00068 42 5846a Corn roots, old tailings 5.02 .00034 68 .105 5847a Corn roots, old tailings 14.42 .00104 72 .040 Average 42 Cultural Experiments 191 ley, wheat and oats were collected in sets of two in a place. One of each set was green, healthy growth, the other more or less yellow and unthrifty in appearance. The object of this method of sampling in soils found to contain small amounts of copper was, if possible, to relate unthrifty appearance of plants exam- ined to copper found in roots and surrounding soil. Table 26 (p. 441) contains the results of the determinations made. As may be expected under field conditions, which are more complex and variable than those of plot or pot cultures, these data are considerably contradictory. Roots of yellow barley, wheat and oat plants, for instance, in 5544a and 5548a contain less copper than roots of strong green plants grown alongside ; although the average copper content (314 parts) of yellow and more or less unthrifty plants is seen to be greater than in green plants alongside (236 parts). So far as observed, the larger percentages of copper found in soils shaken from roots of the plants are always associated with yellow plants. The average copper content of soils from roots of yellow plants is 0.048 per cent, while that from green plants is 0.023 per cent. These observations indicate that in a general way the larger amounts of copper found in these field soils are associated with larger amounts of copper in root systems and with yellow color in young plants. The percentages of copper observed in the soil, ranging up to 0.073 per cent in one instance, is surprisingly high, but toxic effects must be qualified by the character of the compounds, soluble salts in tlie soil, and other factors noted on preceding pages. Yellowness of foliage also may be due to other causes than copper. Among these are: (1) too much water, as in low places; (2) alkali accumulations; (3) cold weather; (4) too much nitrogen in improper form, as in some old barnyards; (5) too little available nitrogen, as on new ground; (6) shade, and (7) insect pests and plant diseases. Malnutrition from any cause, in fact, usually expresses itself in the yellow or striped appear- ance of the leaves of these crop plants. Such appearance, there- fore, cannot be attributed to copper present in the soil, without exclusion of other causes and sufficient confirmatory evidence. As in the case of plot and pot cultures, corn roots are ob- 192 Bulletin 80 served to contain much less copper than other grain roots grown in similar soils, a fact to be attributed to the coarse character of field samples of corn roots. USE OF COPPER SULPHATE TO KILL MOSS IN IRRIGATING DITCHES Clear irrigating water supplies, such as are derived from seepage and from wells, quickly become choked with mosses and algae in warm weather, entailing loss of water and expensive ditch cleaning. In order to test the application of copper to a running stream for the purpose of killing the growth of aquatic plants, an experiment was conducted, in October, 1906, upon the Flowing Wells ditch near Tucson, which at the time contained abundant aquatic growth. A barrel of copper sulphate solution was prepared and placed at the head of the ditch. By means of a small outlet controlled by a stopcock, fifteen pounds per hour of CuSO^.SHoO were added to the ditch flow, this amount being in the proportion of 1 part of copper to 100,000 of water. Most of the copper was immediately precipitated by the bicarbonate of lime present in the water ; still more probably combined in insoluble form with the soil along the ditch; while the remainder acted with toxic effect upon the sensitive algae and the less sensitive mosses {Potomogeions) growing in the water. A short distance below the barrel, where algae and mosses, after twenty-five hours' ex- posure to copper, were brown and dead and breaking away from their points of attachment, .84 parts of copper in 1,000,000 of water remained in solution. Three miles below the barrel, where the mosses and algae were still plainly affected, traces only of dissolved copper were perceptible. A renewal of copper from point to point would therefore have been necessary in treating a long ditch by this method, which, however, proved too costly for adoption in the instance mentioned.'^ It is of interest in this connection to note that in the early days of irrigation on the Gila River, mosses grew in such abund- ance in the clearer waters obtained from the river at that time, T See Bibliography, p. 237, reference 32. Physiological Observations 193 that considerable labor was required to keep the ditches clean. These mosses have now entirely disappeared from the upper canals, due in part to the turbid waters in which they will not grow, and in part, perhaps, to the dissolved copper from the mines. PHYSIOLOGICAL OBSERVATIONS ON TOXIC EFFECTS OF COPPER SALTS Quantitative Work Citrus seedlings placed in copper sulphate solutions contain- ing from 2.5 to 100 parts of copper in 1,000,000 of distilled water wilted in forty-eight hours, thus showing effects of toxicity. Root tips then all turned red with K^FeCyg. Red root-tips sectioned showed under low power red cells under bark and around center. Citrus, cucumber and bitter melilot roots grown in 10:1,000,000 copper solution all gave violet reaction with KOH, less delicate but more distinctive than K^FeCy^, since the purple biuret test indicates both copper and protein. Cultures of wheat, peas, corn, beans, and other. plants grown in soils- containing from 0.005 to 0.1 per cent of copper in soil, gave only very doubtful root-tip reactions with K^FeCye, although showing evident injury, especially in 0.1 per cent cul- ture. There is an essential difference between water-culture roots placed in copper solutions and roots grown in soil. The first are killed by excess of copper salts contained ; the second are yet living and growing resistantly in the soil. A 0.1 per cent copper culture of corn, wheat, beans and cucumbers was washed out from the soil and gave superficial red coloration with K^FeCyc, but' not internal. Living tissue is evidently inconsistent with sufficient amounts of copper to give a plain internal test. Therefore, the small amounts of copper known to be in poisoned but living root systems must be dissem- inated. It is, therefore, of interest to know the copper-protein ratio in poisoned but living root systems, such a ratio being more significant than the ratio of copper to the whole mass of root systems, which includes various proximate principles not con- cerned, in copper fixation. 194 Bulletin 80 Two assembled samples of corn, radish, wheat, vetch and peas grown in soils containing 0.005 per cent and 0.05 per cent of copper were, therefore, very thoroughly washed out, copper determined, and nitrogen determined X ^Vi foi" protein. The amount of copper required to saturate vegetable protein was assumed at 11.7 per cent (14.655 per cent CuO) — the average of figures given in Mann's Chemistry of the Proteids, page 305 (1) Boots grown in .00.5% Cu in soil 4739000 gm. Cu .0105% 0000498 N. 2.26% = Protein 14.125% 0669400 Cu required for saturation of protein .06694 gni. X 11.7% = .007832 gm. Cu for saturation .0000498 ^,„^ Per cent saturated =-^r-—^-^ ^.bSi% (2) Roots grown in .05% Cu in soil 3561000 gm. Cu .0322% 0001147 N. 2.76% == Protein 17.25% 0614900 Cu required for saturation of protein .06149 gm. X 11.7%=: .007194 gm. Cu for saturation , .0001147 , _^,^ Per cent saturated =—-—-—- =l..o94% .00m94 Per cent • saturation Q . Cu p. p.m. of protein Oummary; • jj,.^. i-oQts with copper (1) .005% Cu in soil 105 0.636 (2) .05% Cu in soil 322 1.594 Ratio (1) to (2) 3.07 2.51 In hrief, 10 times as much copper in the soil resulted in 3 times as much copper in the entire root systems and 2.5 times as much in the protein of these root systems. This latter in- crease, however, is responsible for an increase in damage from almost nothing to very severe. Further observations on the copper-protein saturation figure in roots grown in soil containing copper, were made on wheat and Canada peas, planted in pots containing soil mixed with varying percentages of copper in the form of precipitated basic carbonate. The pots contained 102 pounds of sandy loam, and were irrigated in a uniform manner from time to time as water was needed. Plantings were made January 3, 1916, and roots harvested May 15. Physiological Observations 195 TABLE XXVII Observations on the Saturation with Copper op Protein in Roots Grown in Soil Treated with Cu(OH)2.CuC03 4) _ . OS a "p. 5'S 3 '5 s c3 51 00 0) "S 6 a "S^ ■s'si K MC-- CS O ? ^ 'zl ^S ^M a cr « CO t< § ?~ ^• — :- M P. MP. IP J Qt Material ^s ^% p^ 5) -J ci *- Ti 6396 .005 Wheat roots 2.4726 .00023 .1069 .0125 1.84 6397 .02 Wheat roots 4.0122 .00068 :1660 .0194 3.50 6398 .06 Wheat roots 2.2236 .00068 .1231 .0144 4.70 6399 .10 Wheat roots 2.4658 .00037 .1401 • .0164 2.25 6401 .005 Canada pea 1 roots 2.6275 .00085 .3936 .0461 1.85 6402 .02 Canada pea ! roots 2.3844 .00093 .3684 .0431 2.16 6403 .06 Canada pea : roots 2.0056 .00053 .2657 .0311 1.70 6404 .10 Canada pea ; roots 2.2708 .00093 .3747 .0438 2.12 While the figures on saturation in the hist column of the table vary without reference to the amount of copper in the soil and the degree of injury observed in the roots, yet they all show a very low ratio of copper found to copper required for saturation of protein present. In both wheat and peas, injury was first shown at 0.02 per cent of copper in soil, increasing greatly with higher percentages. This injury, showing as a characteristic crinkly condition, is best seen in wheat and corn and has been observed in wheat roots growai in a soil containing as little as 0.017 per cent of copper. A further quantitative study of copper effects on root sys- tems was carried out in water culture with corn, wheat, and Canada peas. Paraffin (parowax) disks one-third of an inch thick and nine inches in diameter were employed, perforated with holes of suitable diameter by means of steel cork borers. These disks were supported on paraffin posts tw^o and one-half inches high in four-quart deep graniteware pans containing the water culture solutions which were used. After soaking, the germinating seeds were planted in paraffin disks of suitable perforation and nutrient solution was then poured up to level of contact with seeds. At first tap-water was used; then a nutrient solution made up as follows : 196 Bulletin 80 KNO3 1.0 gm. -MgSO, - 05 NaCl 5 CaSO, 5 FeClj 04 Tap-water 1.0 liter No phosphate was included because of its precipitating action on copper salts. After the cultures were about four weeks old they were changed to nutrient solutions containing small amounts of copper which was gradually increased from one to ten parts per million of solution. The solution was neutralized with normal H0SO4 (methyl orange indicator) to prevent pre- cipitation of copper by dissolved carbonates. Following is a summary of the history of the cultures, each of which was in- creased to include several hundred plants: Wheat • Dec. 16 Planted in tap-water. Dec. 24 Transferred to nutrient solution, •one-third strength. Jan. 8 Changed to nutrient solution, two-thirds strength. Jan. 14 To nutrient solution, full strength. Jan. 17 To nutrient solution containing 1 part Cu per million. Jan. 21 To nutrient solution containing 2 parts Cu per million. Jan. 25 To nutrient solution containing 6 parts Cu per million. Jan. 28 To nutrient solution containing 10 parts Cu per million. Feb. 9 Experiment terminated. A faint biuret test appeared after addition of 6 p.p.m. Cu. Also dis- tinct KjFeCyo test. Eoots did not become flaccid, but the tops of cul- tures were dying back and prostrated markedly in comparison with roots of control culture. Canada Peas Dec. 20 Planted in tap-water. Dec. 30 Transferred to fresh tap-water. Jan. 6 Transferred to fresh tap-water. Jan. 18 Transferred to nutrient solution. Jan. 20 Changed to nutrient solution containing 1 part Cu per million. Jan. 21 To nutrient solution containing 2 parts Cu per million. Jan. 25 To nutrient solution containing 6 parts Cu per million. Jan. 28 To nutrient solution containing 10 parts Cu per million. Feb. 6-8 Experiment terminated. A faint biuret test appeared after addition of 6 p.p.m. Cu. Distinct KiFeCye test in root tips at end of experiment. Eoots not flaccid, but plants distinctly affected and tops dying back more than those of control culture. Physiological Observations 197 Corn Dec. 22 Planted in tap-water. Jan. 8 Changed to nutrient solution, one-tliird strength. Jan. 19 To nutrient solution containing 1 part Cu per million. Jan. 21 To nutrient solution containing 2 parts Cu per million. Jan. 25 To nutrient solution containing 6 parts Cu per million. Jan. 28 To nutrient solution containing 10 parts Cu per million. Feb. 9 Experiment terminated. Giving distinct, faint biuret test after addition of 6 p. p.m. Cu; also KiFeCjs test at end of experiment. Eoots not flaccid at end of experi- ment, but tops of cultures about half dead, while tops of control culture were still in good condition. These cultures, as shown by the notes, were exposed to cop- per solutions — wheat twenty-three d^ys, peas eighteen days, corn twenty-one days. At the end of the experiment roots were not flaccid, but very faint biuret and distinct ferrocyanide tests were observed. In all cases top growth was affected, corn most, wheat next, and peas least. This material, as indicated above, is poisoned only just enough to show reactions in root tips, although tops are distinctly affected. It, therefore, represents minimum rather than maximum toxic conditions. Material was harvested and analyzed to show copper and nitrogen ratios; and by estimating the number of root tips in samples of corn, peas, and wheat the amount of copper per root tip, required to show faint tests, was found. TABLE XXVIII Quantitative Determinations on Water Cultures Showing Slight Toxic Effects Corn No. 6321 Sample 265 tops Di-\' matter, fjrams 17.695 Cu found, grams .00048 Cu p. p.m. in dry matter 27.10 6320 1 6323 j Coarse roots 2.4277 .00022 91.00 6319 1100 root tips .77 .00042 545.50 Amount of copper per root tip associated with slight toxic effects, .00042 -^ 1100 = .000000382 gm. 198 Bulletin 80 Peas Dry matter, Cu found, Cu p. p.m. in No. Sample grams grams dry matter 6327 250 tops 7.0850 .00012 16.90 6325 Coarse roots 1.2827 .00180 1400.00 6326 Fine roots .8393 .00141 1680.00 6324 5500 root tips .4462 .00153 3428.00 Amount of copper per root tip required to show slight toxic effects, .00153 H- 5500 = . 000000278 gm. Total roots examined for nitrogen 4.41730 gms. Albuminoids in roots (Alb. N. X H) 83929 Copper required to saturate albuminoids (factor 11.7%) .09819 Total Cu found : 00784 .00784 ^^^^ Saturation 09819 ~ ^^^ Wheat Dry matter, Cu found, Cu p. p.m. in No. Sample grams grams dry matter 6332 .530 tops 12.7 .00165 129.90 6331 Eoots .6902 .00020 297.00 6330 16000 root tips .3664 .00103 2811.00 Amount of copper per root tip associated with slight toxic effects, .00103 -^ 16000 =: .000000064 gm. Total roots examined for nitrogen 2.9223 gms. Albuminoids in roots (Alb. N. X 6i) 30794 Copper required to saturate albuminoids (factor 11.7%) .03603 Total Cu found - - 001789 .001789 , . -^ Saturation 03603^ ~ 4.96% These figures show, as usual, relatively small amounts of copper in tops of plants, with large amounts in roots, increasing from coarser to finer portions, until in the root tips corn con- tains 545, peas 3428, and wheat 2811 parts per million of copper in dry matter. For peas and wheat these are the largest pro)>or- tions of copper thus far observed in any plant samples. When the total amount of copper found in each sample is divided by the number of root tips employed, an extraordinarily small amount of copper is found necessary to bring about toxic effects. For instance One corn root tip (terminal 3 cm.) required 000000382 gms. Cu One pea root tip (terminal 1 cm.) required 000000278 gms. Cu One wheat root tip (terminal 1 cm.) required .000000064 gms. Cu Physiological Observations 199 Moreover, the extent to which albuminoids in affected roots are saturated with copper — only 7.99 per cent for peas and 4.96 per cent for wheat — indicates a maximum effectiveness upon roots of small amounts of the metal. Reactions of Copper with Growing Points Coi'n seedlings fifteen .days old were fixed with cotton, in tall 50-c.c. graduated Nessler tubes containing different strengths of copper sulphate in pure distilled water. The strengths of solution employed' were 20, 10, 5, 2.5, and 1.25 p. p.m. There was a check culture with no copper. After three days, in all cases except the check, the roots were flaccid, showing contraction on graduations and giving biuret and ferrocyanide tests, increasing in strength from w^eaker to stronger concentration. An experiment with pea seedlings gave similar results, but when the quantity of pea roots was increased and weak solutions, 2.5 and 1.25 p. p.m., were employed in small quantities (20 c.c), the tests became much fainter. Severed roots of corn, also, were observed to give as good tests as roots of living plants. A large number (seventy) of severed root tips placed in a small quantity' (20 c.c.) of weak solution (5 p.p.m.) gave only a faint ferrocyanide test. These observations indicate that the concentration of copper in growin^^j points is due to ionic dissociation and migration through the semi-permeable membranes of the root systems,'* rather than to transpiration. The fainter test for copper in large quantities of root material indicates lessened toxicity of dilute solution-; of copper in presence of excess of root materials. Mature wheat, corn and pea plants in nutrient solutions, but not growing actively, were treated with gradually increasing amounts of copper from January 21 to February 2, as follows : Wheat, Corn, and Pka Plants, Thirty-seven Days Old, Treated with Copper in Nutrient Solution Jan. 21-25; nutrient sol. w. 2 p.p.m. Cu. Jan. 25-28; nutrient sol. w. 4 p.p.m. Cu. Jan. 28 to Feb. 5, nutrient sol. w. 10 p.p.m. Cu. s See Bibliography, p. 237, references 35, 36, 37, 38, 39, 40, 41, 42, 43. 44. 200 Bulletin 80 Feb. 5; very faint biuret test for copper, distinct ferrocyanide test. Corn, forty-eight days old in 50 p.p.m. Cu sol., two days, gave faint biuret and ferrocyanide tests. Corn, forty-eight days old in 500 p.p.m. Cu sol., two days, gave faint tests for copper. From these observations it is evident that the nearly negative results shown are due either to nutrient salts present or to the older and therefore more quiescent material employed. To settle this question, the following experiments were made : (1) Young (ten days) wheat and corn plants were placed in copper solution in distilled water and in nutrient solutions and observed after twenty and forty hours, as follows : 2.5 p.p.m. Cu, distilled water — 20 hours 10 days old: Young wheat; flaccid?; strong biuret test; strong KiFeCye test 60 days old : Old wheat ; not flaccid ; no strong biuret test ; distinct K^reCys test 10 days old: Young corn; flaccid; strong biuret test; strong KtFeCje test 60 days old: Old corn; flaccid; no biuret test; old tips, faint K^FeCye test young tii)S, strong KiFeCye test 10 p.p.m. Cu, distilled water — 20 hours 10 days old: Young wheat; flaccid?; strong biuret test; strong KiFeCys test 60 days old : Old wheat ; not flaccid ; faint biuret test ; distinct KiFeCys test 10 days old: Young corn; flaccid; strong biuret test; strong KjFeCys test 60 days old: Old corn; flaccid?; distinct biuret test; strong KiFeCye test 40 p.p.m. Cu, distilled water — 20 hours 10 days old: Young wheat; flaccid; strong biuret test; strong KiFeCys test 60 days old: Old wheat; flaccid?; faint biuret test; distinct K^FeCyc test 10 days old: Young corn; flaccid; strong biuret test; very strong KiFeCye test 60 days old: Old corn; flaccid; strong biuret test; strong KiFeCye test The above results indicate that old roots of corn and wheat are more resistant to the penetration of copper than are the young roots. This is shown by less flaceidity in the weaker solu- tions and by the fainter tests observed. A second series with greater strengths (5, 20, and 100 p.p.m.) and longer exposure (forty-five hours) showed distinctly less differentiation than in the case of the series above given in detail. This is to be expected, inasmuch as stronger solutions must overcome resistance of roots exposed to them more quickly, and the longer time employed would likewise tend to overcome differences existing in the first few hours of the experiment. Physiological Observations 201 (2) Young and old wheat and corn roots were placed in 10 p.p.m. Cn in distilled water and 10 p.p.m. Cu in nutrient solution. with the following results : 10 J).]). 111. Cu, distilled water — 20 hours 10 days old: Young wheat; flaccid?; strong biuret test; strong KiFeCyo test 60 days old: Old wheat; not flaccid; faint biuret test; distinct K^FeCy^ test 10 days old: Young corn; flaccid; strong biuret test; strong KiFeCyo test 60 days old: Old corn; flaccid; distinct biuret test; strong KiFeCy,, test 10 p.p.m. Cu, neutralized nutrient solution — 20 hours 10 days old: Young wheat; not flaccid; doubtful biuret test; faint K,FeCy6 test 60 days old: Old wheat; not flaccid; none or doubtful biuret test; faint K^FeCy^ test 10 days old: Young corn; not flaccid; faint biuret test; distinct KjFeCys test 60 days old: Old corn; not flaccid; distinct biuret test; distinct KiFeCy^ test This shows very distinctly the prevention of toxic action upon plant roots through the protective action of other solids in solu- tion, as already observed in water cultures by measurements of root growth. It is noteworthy in this connection that corn roots generally seem to be more sensitive to the action of copper salts than the roots of w^heat or peas. In order to examine still further into the relative resistance of old and young root systems to copper salts, a solution of 5 p.p.m. Cu in distilled water was used, the time being varied from twenty to two hundred hours. The results of these obser- vations indicate that, with wheat and corn roots, the penetration of copper is distinctly more rapid in young than in old material. Peas did not give clear results. It appears from these observations, first, that the accumula- tion of copper in plant roots is distinctly due to the migration of dissociated ions into the root systems, where they are fixed by protoplasm, in which combination they are identified by means of the biuret test. Second, the presence of nutrient salts very distinctly lessens the effect of a 10 p.p.m. copper solution upon sensitive young growing plant roots. Third, old quiescent plant roots developed in a nutrient solution are distinctly less sensitive to copper salts than young roots which are still actively growing. 202 Bulletin 80 The slow development of biuret tests for copper in such material after sufficient exposure to copper solutions, indicates the presence of protoplasm. It is possible that the same observations may apply to other poisons, metallic or otherwise, brought into contact with absorp- Fig. 13. — Photomicrograph of root tip of corn grown in water culture and poisoned by 1:200,000 of Cu in solution. The copper is shown as red copper ferrocyanide, which appears black in the photomicrograph. The irregular inner black line show^s the penetration of the copper and also indicates sharply the differences in permeability of adjacent cells, some of which are penetrated before others. ( X 80 diam.) (Photo by J. T. Barrett.) Diagnosis of Copper In.jtry 203 tive root systems in the soil. Not only this, but it may be true that nutrient salts, as well, will be found more actively absorbed by younger and more sensitive root systems than by older ones, or by root systems which for any reason have become quiescent. This would suggest the possibility of choosing to advantage the proper time for applying substances, either to avoid injury or, as in the case of fertilizers, to secure maximum benefit from them. Varying Resistance of Individual Cells to Copper Not only do old and young roots vary as to toxic effects upon them of copper, but different degrees of resistance between individual cells in the same root and even in the same chain of cells, is clearly shown in the photomicrograph (fig. 13) of a corn root tip which has been exposed to a 1 to 200,000 solution of copper, then colored with K^FeCy,,, and sectioned for obser- vation. The dark, abruptly angular line of penetration shown in the section plainly indicates that individual cells may be penetrated by copper while adjacent cells growing under pre- cisely similar physical conditions are not penetrated. If this be not due in some unseen way to morphological peculiarities of root structure, it must be due to individuality in the cells themselves, some of which must be more resistant to penetration by dilute copper solutions than others. Summing up the physiological observations relating to effects of copper upon plants, we find (1) that individual cells vary (probably) in degree of resistance to penetration by copper salts; (2) that young roots are less resistant than old roots; (3) that roots of certain species of plants (e.g. corn) are less resist- ant than roots of other species; and (4) that toxic effects may be to some extent related to the structure and distribution of root systems. DIAGNOSIS OF COPPER INJURY In the presence of toxic amounts of copper in the soil, the root systems of culture plants become harsh and crinkly with almost entire loss of root hairs. Consistent with the checking of growing points, root systems are also greatly restricted in extent, 204 Bulletin 80 and in feeding capacity. Individual roots are coarse, covered with thick epidermis, and are abruptly angular, apparently as a result of chemotropic contortions. Root tips are shortened and thickened and in some instances are strongly proliferated. The anatomical structures associated with these changes in form are very striking. In corn the cells of the primary cortex, in normal roots, are elongated parallel with the axis of the root, and in longitudinal tangential section measured about 74 by 30 microns. Injured cells of corn grown in soil containing 0.1 per cent copper gave longitudinal tangential sections approximately 34 by 30 microns, as shown on accompanying drawings. (See, also, plates II, III, and rV. U HUn --- )-* u-i >- ~ ^ ^ u a b Fig. 14. — a. Tangential longitudinal section of corn root grown in soil containing .1 per cent of copper as copper sulpliate, showing cells of cortex of injured rootlet, b. Tangential longitudinal section of normal corn root cells of cortex. (X ± 300 diam.) (Sections by G. F. Freeman.) These structural moditications, taken in connection with other symptoms and conditions and in the absence of other causes, such as an excess of alkali salts, ** confirm a diagnosis for copper injury in a soil of doubtful toxicity. For instance, March 4. 1916, two sets of samples of barley were collected in the district studied, and the material examined for evidence of copper in- jury, as follows : Lot 1. — Young barley plants from the upper end of a field midway between Safford and Solomonville, under Montezuma Canal. The soil next the ditch shows old tailings, and there are irregular areas of yellow barley immediately under the canal. 9 See Livingston, Botanical Gazette, vol. 30, no. o, p. 229, 19O0. [^M t^ ^ bJD ^ p^ s K Ph S d >% O cc m o fi o £ C^ c o M S bi3 < S 02 -t^ • ^ r-* rt — K* f-H c rH bX o o -t^ o =H c o r-» ^ -H a? o c; CO bij !^ ,— . .- tc 2 ■^ 4J ^ o o ^ M ^ 1-1 01 rig. 1 Fig. 2 PLATE III Fig. 1.— Individual roots of corn injured by 0.1 per cent of copper added as copper sulphate to the soil. Fig. 2. — Individual root of corn, normal. (Photos by G. F. Freeman.) Fig. 1 Fig. 2 PLATE IV Fig. 1. — Thickened rootlets and proliferated root tips of corn injured by 0.1 per cent of copper added as copper sulphate to the soil. (X 3 diam.) Fig. 2. — Fine roots and root tips of corn, normal. ( X 3 diam.) (Photos by G. F. Freeman.) Diagnosis of Copper Injury 205 Sample „ Yellow barley plants No. 6343 Roots, crinkly and angular, much branched near surface. Dry weight, 3.2429 gms; Cu, .00085 gm; p.p.m 262 6344 Soil shaken from yellow barley roots Copper 07979% Total soluble solids (alkali) 46400 CI as NaCl OO'i Sodium carbonate 008 Nitrogen ^^^ T). Green barley plants from near (a). 6345 Roots, smooth and straight, not much branched near sur- face. Dry weight, 1.6025 gm ; Cu, .0002 gm; p.p.m 125 6346 Soil shaken from green barley roots Copper 05844% Total soluble solids (alkali) 45600 CI as NaCl 00^ Sodium carbonate none Nitrogen 1^^ lot 2. — Young barley plants from the upper end of a field in West Layton under Montezuma Canal. Soil near ditch known to contain tail- ings and showing spots of yellow barley at head of field. Sample a. Yellow barley plants No. 6347 Roots, crinkly and angular, much branched. Dry weight, 3.2977 gms; Cu, .0014 gm; p.p.m 425 6348 Soil shaken from roots of yellow barley plants Copper 1113% Total soluble solids (alkali) 50 CI as NaCl -008 Sodium carbonate 008 Nitrogen '"'^ h. Green barley plants from near (a) 6349 Roots, smooth, straight, not much branched. Dry weight, 2.2473 gms; Cu, .0003 gm; p.p.m 133 6350 Soil shaken from roots of green barley plants Copper 02678% Total soluble solids (alkali) : 40 CI as NaCl 008 Sodium carbonate 004 Nitrogen 1^^ 206 Bulletin 80 Considering the above observations, we notice that the soils from which samples were taken do not contain injurious amounts of soluble salts. Their nitrogen content, also, is normal. The areas of yellow barley from which samples come are therefore not to be attributed to alkali- salts, or to abnormal nitrogen content. Observation in the field, also, failed to indicate that conditions of irrigation, temperature, or light were unfavorable, these condi- tions being the same for both green and yellow samples. Excluding these considerations, therefore, we now find that there is uniformly more copper in the roots of yellow barley plants than in those of the green ones, also in the soils in which they occur. The roots of yellow plants, moreover, show the crinkly condition caused (though not exclusively) by copper when present in toxic amounts in the soil. The following state- ment summarizes these observations. Lot 1 Cu in soil Cu p. p.m. per cent in roots Condition of roots Yellow barley .0798 262.00 Crinkly and branched Green barley • .0584 125.00 Lot 2 Straight, not branched Yellow barley .1113 425.00 Crinkly and branched Green barley .0268 133.00 Straight, not branched The evidence therefore indicates quite conclusively that the two yellow samples owed their color to toxic effects of copper upon the roots of the young plants. Later in the season, how- ever, no difference in mature plants, showing variations in color when young, may be observed. This must be due to the fact that as root systems penetrate more deeply into the soil they escaj^e the surface zone of tailings, with consequent recovery from the effects of copper. General Discussion 207 Partll.-GENERAL DISCUSSION PRELIMINARY STATEMENT The copper compounds, in solid form and in solution, that result from mining operations in the Clifton-Morenci district, have found their way down the San Francisco and Gila rivers to the underlying irrigated agricultural soils of Graham County in sufficient amounts to raise the question of their toxicity to crops. The largest amounts of copper in these soils are found at the heads of irrigated lands, especially where alfalfa is or has been, at which points old accamulations of tailings, laid down for the most part prior to 1908, are still to be found. Accumulations op Copper The amounts of copper accumulating in the Gila River valley soils in this way are small, the observed range being from 0.006 per cent to 0.111 per cent in surface soils and the average for eighteen soils analyzed being 0.046 per cent of copper. Irrigated soils elsewhere have been observed to contain larger quantities of copper than those above noted, for instance 1.002 per cent on the Deer Lodge River below Anaconda, Montana, with an aver- age of 0.09 per cent for eleven other samples taken in the same locality.^** These amounts of copper in a soil may or may not be toxic according to the combination in ^\hich the copper exists, the physical character of the soil and its chemical composition, climatic and moisture conditions, the crop grown, and other con- siderations which may now be discussed in order. The small amounts of soluble copper constantly coming down stream from the mines which cannot, like solid tailings, be en- tirely excluded from irrigating water supplies, are of importance because of their tendency to accumulate by reason of the fixing power for copper of silicates, carbonates and organic matter in the soil. The completeness of this fixing power of soil for copper is shown by several experiments in which solutions of copper 10 U. S. D. A. Bur. Chem., Bull. 113, p. 34, 1907. 208 Bulletin 80 salts were percolated through one to twelve inches of soils, with little or no copper appearing in the filtrates. Under field con- ditions, therefore, this action tends to concentrate dissolved copper in irrigating water in the surface few inches of the soil. A series of samples of Montezuma Canal water taken at Solomonville affords quantitative suggestions in this connection : TABLE XXIX Copper Content of Gila River Waters Approx. amts. of Amounts of Cu added Approx. copper in irrigation, estimated flow of carried in p. p.m. of water Gila down River stream, Sample No. and In In in sec. 1 day date Description tailings solution Total ft. lb. 3309 May 26, '04 River very low 18.3 .80 TO.] 30 3094 3486 June n. "0.1 Small flood 2-5 170 230 (Soluble only) 3622 June 25, '06 River low 1.6 .11 1.71 3737 Feb. 22, '07 Medium flood trace 2.88 ±3.0 600 9720 4011 Jan. 3, 'OS 2.1 .08 2.18 Tailings shut out of river May 1, 1908 4029 Apr. 12, '09 1.4 .08 1.48 6342 Mar. 4,'16-- .04 .03 .07 * Following four-months shut-down of operations in Clifton-Morenci district. These figures, while somewhat meagre, seem to indicate a lessening Avaste of copper downstream following the restraint of tailings from the water-supply in May, 1908. This is especially true of copper in solution, due probably to the decreased amounts of solid copper compounds in suspension from which copper in solution is derived. Assuming at the present time an average of 1 part of copper in 1,000,000 of Gila River water, four acre-feet of such water, required for one year's irrigation, would contain 10.9 pounds of copper, from which should be deducted small losses due to vegetation, drainage waters, and percolation to depths below the surface soil. Six tons of alfalfa v^ath a copper content of 5 p. p.m. contain 0.06 lb. copper; while one acre-foot of seepage water (about the annual seepage loss) containing 0.25 p.p.m. copper would carry 0.68 lb. copper. Estimating the total loss roughly at one pound General Discussion 209 of copper per acre a year, the net addition of copper to the soil would be approximately ten pounds, or about 0.00025 per cent. It would therefore require about forty years to accumulate 0.01 per cent of copper in the surface foot of soil. Inasmuch as, under field conditions, this is not an injurious amount, there is little likelihood, considering the district in a general way, that the small residues of copper now coming down stream will accumu- late to an injurious extent within a reasonable period of time. Incidentally, it is of interest to note the large total losses of copper (3094 lb. and 9720 lb. per day observed) formerly result- ing from mining operations in the district. Possible Effects upon Health With reference to the question of poisonous effects upon man and animals of dissolved copper in irrigating and well-waters, such effects, in general, are much less upon animals than upon plant life. Moore and Kellerman state, for instance, that 0.02 gms. of copper may be absorbed daily by a man with safety." This amount of copper would be contained in five gallons of water containing one part per million of copper, the largest amount of copper observed in a well-water in the district studied being 0.53 p. p.m. It is of interest in this connection to note a belief of the copper miners of the Rio Tinto in southern Spain, where the wells are impregnated with copper, that one part of copper per million of drinking water is permissible, but that two parts per million result in "copper colic." "" In view of experi- ments upon human subjects, however, it is more than likely that deleterious effects observed are due to associated compounds in the water. It is of importance to note that a strength of as little as one part per million of copper in pure water will de- stroy algae, which are common in clear water supplies freely exposed to light and air. This fact may be made of use in clean- ing ditches and reservoirs of aquatic growth, where the expense is not too great. The germicidal effects of small amounts of copper in waters of the district studied also have a bearing upon human health. 11 U. S. D. A. Bur. PI. Ind., Bull. 64, p. 23. iia Conversation of J. W. Bennie, Clifton, Arizona. 210 Bulletin 80 Bacilli of various species reacting upon human health are very sensitive to the action of soluble copper salts. For instance, in distilled water "one part copper in 16,000,000 parts water killed typhoid bacilli in two hours. In copper solutions made up with tap and sea water, the action was still marked, but less vigorous than in distilled water. ' ' ^- Moore and Kellerman state that one part of copper sulphate to 100,000 parts of water destroys typhoid and cholera germs in three to four hours. ^•" In milk supplies as little as one part of copper salts in 2,000,000 of water acts as an antiseptic against putrescent bacteria.^'' It seems, therefore, that there is a possibility that the amounts of copper observed in ditch and well-waters in the district may have an antiseptic effect upon malignant germs, more particularly typhoid fever, likelv to occur in the district.^'" Amounts and Significance of Copper in Aerial Vegetation The amounts of copper found in aerial parts of vegetation within the district are small, ranging from a trace to 7.6 parts copper in ], 000.000 of dry matter and averaging 3.41 parts. Miscellaneous cultures in water, potted soils, and plots gave larger amounts of copper which, however, were associated in most cases with toxic effects. Table 30 (p. 462) contains a sum- mary of these data. Even allowing for errors of method and of analysis, the European figures (3) seem excessively high, although the woody character of most of the samples was for the most part very different from that of the tender crop plants of the Arizona series. Little can be said as to the toxic effects of the copper ob- served in aerial plant parts in the Arizona samples. The yellow striping of copper-poisoned corn is probably a general symptom of malnutrition to be attributed to the effect of copper upon root systems rather than upon leaves and stems. In rare instances, however, beans and squash in water culture showed dark green 12 Biochem. Jour., Aug., 1908, pp. 319-323. 13 U. S. D. A. Bur. PI. Ind., Bull. 64, p. 43. 14 Jour. Ind. and Eng. Chem., Sept., 1909, p. 676. 15 See Bibliography, p. 236, references 3, 20, 21, 22. General Discussion' 211 TABLE XXX Summary of Copper Content of Aerial Vegetation Mill. Max. Ave. No. of . — -' ^ samples Parts per million copper 1. Field vegetation from upper Gila...'. 10 trace 7.60 3.41 Field vegetation from other sources in Arizona 9 none 6.30 1.52 2. Corn plants grown in pots .01-.05 per cent Cu 3 6.5 21.00 13.30 Tops of corn, beans and squash grown in Cu water culture 6 11.7 32.00 22.90 Tops of corn, beans, etc., irrigated with copper solutions 14.00 Beans in soils containing Cu 9 13.0 44.00 26.00 Squash ditto 5 14.0 61.00 39.00 Corn ditto 20 4.4 239.00 42.00 3. Field samples collected by Leh- naanni« i3 0 560.00 86.00 Field samples collected by Ved- rodii" 1894 26 40.0 1350.00 257.00 189.5 26 10.0 680.00 151.00 patches that may possibly have been due to presence of copper, inasmuch as appearances of this character are sometimes noted as an effect of the application of Bordeaux mixture. Bain states, for instance, that extremely minute amounts of copper stimulate formation of chlorophyll in a cell and therefore in- crease the formation of starch.i^ Ewart. also, shows that solu- tions of copper as dilute as 1 to 30,000,000 prevent the action of diastase upon starch.^^ It is possible, therefore, that the juices of plant tissues containing traces to 239 parts (observed) of copper in 1,000,000 of dry matter may carry sufficient of this amount in solution in the cell sap to hinder the action of enzymes upon starch, and thus prevent its normal translocation. 16 Dcr Kupfergelialt von Pfianzcn und Thieren in Kupferreichen Gegen- den, Lehmann Arcliiv fiir Hygiene, vol. 27, pp. 1-17, 1896. 17 Quoted in Brenchley, Inorganic Plant Poisons, p. 17, 1914. 18 Bain, Tenn. Agr. Exp. Sta., vol. 15, Bull. 2, p. 93, 1902. i9Ewert, Zeitschr. fiir Pflanzenkrankli., vol. 14:3, p. 135, 1904. 212 Bulletin 80 Amounts and Significance of Copper in Root Systems Of far more and unmistakable importance is the effect of copper on root systems of plants. Under all conditions, whether grown in water culture, in pots, plots, or as field crops, the root systems of plants contain much greater amounts of copper than do the aerial portions, as is shown briefly in the following con- densation of results : TABLE XXXI Summary op Copper Content of Tops and Roots op Plants Cu in p. p.m. No. of , ^ \ samples Tops Roots Ratio Corn, beans, and squash in water cul- tures, poisoned but living 3 22.00 103.00 1 to 4.7 Ditto— killed by copper 3 23.00 268.00 1 to 11.6 Corn grown in soil containing .01 per cent of Cu as Cu(0H),CuC03 1 6.50 152.00 1 to 23 Corn grown in soil containing .025 per cent Cu as Cu(0H),.CuC03 1 21.00 728.00 1 to 35 Corn grown in soil containing .05 per cent Cu as Cu,S 1 12.50 171.00 1 to 14 Bean series grown in soils containing Cu as pptd. carbonate .0025 to 1.5 per cent Cu in soil 9 26.00 1431.00 1 to 55 Corn series grown in soils containing Cu as CuoS .01 to 1 per cent Cu in soil 7 51.00 702.00 1 to 14 Corn series grown in soils containing Cu as ehrysocolla, .05 to 1 per cent Cu in soil - 3 13.00 266.00 1 to 20 Corn series grown in soils containing Cu as pi)td. carbonate, .0025 to .05 per cent Cu in soil 4 13.00 . 416.00 1 to 32 Excluding samples grown in water cultures, the roots of which were cleaned with 4 per cent HCl, probably with loss of some copper, the root systems of experimental cultures contained averages of from fourteen to fifty-five times as much copper as the aerial portions of the plants. Furthermore, fine roots of corn were found in one instance to contain about three times as much copper as coarse roots of the same sample, and, finally, the maximum amount of copper, as determined both by analysis and by observation, in water cultures, was found in the root tips General Discussion 213 of plants affected by copper. Analyses of water cultures of corn, peas, and wheat showing slight toxic effects gave the following ratios of copper in tops, root systems, and root tips : Water cultures Cu in p. p.m. showing slight , '^ ^ toxic effects Tops Roots exclusive of tips Root tips Corn 27.00 91.00 545.00 Peas 17.00 1400.00 3428.00 1680.00 Wheat 130.00 297.00 2811.00 The root tips in this material, by means of caustic potash (the biuret reaction) and potassium ferrocyanide, show the char- acteristic purple and dark-red reactions due to copper. In the former case not only copper, but copper in combination wiih proteids, is indicated — the purple color being due to the biuret test, which identifies both copper and proteids simultaneously. In roots grown in water culture, and then subjected to the action of dilute copper solutions, the location of copper in a poisoned root system can be seen under a low power with con- siderable exactness. The purple of the biuret test begins very definitely with the growing point of the root tip and fades out gradually in comet-like fashion usually within one or two millimeters distance of the tip. New growing points in process of pushing their way through the epidermis along the sides of the roots likewise give a strong but very local biuret reaction. This combination of copper (in the form of oxide) and proteids is one used for the precipitation of albuminoid nitrogen in chem- ical analysis of feeding stuffs.-" The amount of copper entering into the combination varies with proteids from various sources. As a rule, animal proteids combine with much less copper than vegetable proteids — averaging about 2.4 per cent of copper for egg albumin. Vegetable proteids combine with from 11.60 to 16.97 per cent of copper oxide and average 11.7 per cent cop- per.-^ Ordinarily, therefore, a vegetable proteid would be sat- urated with about one-ninth of its Aveight of copper; but its physiological activities are disarranged and the root killed by much less than the amount required to saturate the proteid. 20 See Bibliography, p. 237, reference 48. 21 Mann, Chemistry of the proteids, p. 305. 214 Bulletin 80 For instance, in samples of wheat and pea roots grown in water culture, it was found by means of nitrogen and copper deter- minations, using the factor 11.7 per cent copper for saturation of albuminoids, that in wheat roots 4.96 per cent of the copper required for saturation was present and in pea roots 7.99 per cent. It appears, therefore, first, that copper attacks plant proteids at the most delicate and vulnerable points in the whole plant organization — the growing points of the root systems ; and, sec- ond, that a small proportion of the copper required for complete reaction is sufficient to kill the protoplasm at these points. Again, it is to be observed that, especially in the seedling stages of growth, the number of growing points is small so that only extremely minute amounts of copper are required to arrest the growth of root tips, the spread of root systems and the nutrition of the plant. Inasmuch, also, as plants vary greatly in the physical struc- ture and the physiological activity of their root systems, includ- ing the number, delicacy and absorptiveness of their growing points, it is not unlikely that the varying sensitiveness to copper salts of different plants, and of the same plant at different ages, may be explained by these observations. Corn, for instance, the most sensitive plant worked with, is characterized in its seedling stages by a small number of vigorously absorptive growing points. By means of the more delicate dark-red potassium ferro- cyanide test, copper may usually be traced through the vessels of the root systems for considerable distances, showing that it is through these channels that small amounts of the metal finally reach the stems and leaves. Here the maximum amounts of copper are found in the outer and upper portions of the plant, where evaporation is mo.st active, and where the greatest residuum of copper therefore occurs. The potassium xanthate (yellow) and hydrogen sulphide (brown) tests also reveal copper in root structures but are not so satisfactory for this purpose as potas- sium ferrocyanide. (See frontispiece.) The above described reactions, which are so conspicuous in water-culture material killed by copper, are very obscure or imperceptible in roots grown in soils containing copper. The General Discussion 215 first material, however, is dead and more nearly saturated with copper; while living roots from soil culture, with proteids com- bined to but a sinall per cent of their capacity for copper, do not give satisfactory color tests. These reactions, therefore, do not serve for qualitative determinations of toxic effects in field material. Relations Between Amounts of Copper in Root Systems and Injury to Plants An effort to establish relations between the amounts of copper in parts per million of dry matter in root systems, and toxic effects as shown in the condition of aerial portions -of the plant, was only partially successful; but a sufficient number of observations on samples of sufficient size produced under care- fully regulated conditions would probably establish such rela- tions. In the tables shown on the preceding pages there is a fair degree of agreement between the members of each experi- mental series, the copper found in root systems increasing in most cases with the amount of copper in the soils of each particu- lar series of cultures. In the case of beans and corn grown in cul- tures containing copper in the form of precipitated carbonate, beans show a somewhat higher resistance to toxic effects and also contain larger amounts of copper in the root systems throughout the series. The conditions under which the samples were grown seem to have, within limits, more effect upon the copper content of root systems than the amounts of copper in the soil, as is indicated in the following tabular statement : TABLE XXXII Toxic Concentrations of Copper in Soils and Root Systems Cu in root Cu in root Points at system at point system at which toxic not showing point showing effects toxic effects toxic effects Culture begin p. p.m. p. p.m. Corn, seven samples from field soils 42 at .07% Corn in field plots containing Cu as sulphate 04% 245 at .025% 296 at .05% Corn in pot cultures containing Cu as carbonate 023% 748 at .02% 509 at .025% Beans in pot cultures contain- ing Cu as carbonate 035% 950 at .025% 1358 at .05% 216 Bulletin 80 111 this stateiiieiit, for instance, field samples of corn roots grown in soil containing 0.07 per cent of copper contained only 42 p. p.m. of copper in dry matter, while a plot sample grown in soil containing .025 per cent of copper contained 245 p. p.m. of copper in dry matter, and corn grown in pot culture containing 0.02 per cent of copper in soil contained 748 p.p.m. of copper in dry matter. These differences may be due to the coarser root systems of plot and field-grown samples, this condition being associated with relatively small amounts of copper in dry matter. In view of the great labor involved in preparing root samples for analysis and the very variable results obtained from copper determinations made upon svicli material, there seems to be little hope of estab- lishing satisfactory ratios of copper to dry matter for the pur- pose of determining that a sample of field material has been injured by copper. It is probable, however, that for comparative purposes, pot cultures of field soils conducted under uniform and carefully regulated conditions, with standard plants of knoM'U behavior, may yield figures of comparative value in de- termining the character, toxic or otherwise, of a soil containing copper. Corn is an excellent summer-growing plant for the pur- pose, inasmuch as it shows toxic effects easily, grows rapidly, and affords abundant root materials for analytical determinations. For winter cultures, wheat serves well. Both plants are repre- sentative of standard crops for the region under discussion. Pathological Effects Pathological effects in tops and roots may confirm to a con- siderable extent, the fact that a plant has been poisoned by cop- per. The lengthwise yellow striping of corn and wheat leaves due to toxic amounts of copper is not distinctive since the same appearances may result from various other conditions in- ducing malnutrition, such as those mentioned on a preceding page. Usually, however, careful observation will identify or eliminate these other disturbing factors. Root systems grown in coppered soils are also conspicuously injured, being stunted in growth, of harsh and crinkly texture General Discussion 217 and (in the case of corn) showing characteristic proliferated root tips. The epidermis is thick and rough and the cells in longi- tudinal tangential section contract from the oblong toward the circular form. Here, again, other factors, such as alkali salts in excess, may lead to similar appearances: and these must be eliminated in a diagnosis of copper injury. Soil Conditions Relating to Toxic Effects of Copper upon Plants Certain conditions favor, others oppose the toxic action of copper under field conditions, the general tendency being to modify or do away with toxic effects, where the amounts of copper are not excessive. Carhon dioxide in the soil, alone and in conjunction with cer- tain salts (NaCl, NaoSOJ tends to form solutions of basic cop- per carbonate. Carbonates (Na,C03,CaC03) lessen the solubil- ity of basic copper carbonate in carbon dioxide and, therefore, the toxicity of copper compounds in soils containing these carbonates. '-- Coarse, sandy soils favor toxicity by permitting free move- ment of solutions and because the withdrawal in them of copper from solution by physical and chemical reactions is minimum.-^ The character of the compound of copper to which roots are exposed is important. In pot cultures of precipitated carbonate of copper, of sulphide in the form of chalcocite pulverized to go through a 100-mesh sieve, and of silicate in the form of chryso- colla pulverized to 100-mesh, toxic effects appeared with corn as follows : Pot culture of corn; Cu in form of pptd. carbonate— showing toxic effects at .023% Cu in soil Pot culture of corn; Cu as chalcocite, 100-mesh— showing toxic effects at .08% Cu in soil Pot culture of corn; Cu as chrysocolla, ]00-mesh— showing toxic effects at .08% Cu in soil The precipitated carbonate is not only more soluble in car- bon dioxide than in chalcocite, but also more easily acted upon 22 See Bibliography, p. 236, reference 12. -■'■ See Bibliography, reference 18. 218 Bulletin 80 by the acids of plant roots than chalcocite or, probably, chryso- colla. Under field conditions, copper in tailings is originally mostly in the form of sulphides, chiefly chalcocite, which oxidizes only slowly to sulphate in presence of water and air. Chalcocite, 3.2 grams, shaken up with 600 c.c. of water, and air, for twenty- eight days, yielded only 16 mg. of soluble copper. The soluble sulphate in contact with silicates and carbonates of the soil is converted to insoluble forms. The process is gradual and the amount of soluble copper present at any one time is small. The tilth of the soil is significant. A pot culture very thoroughly mixed with 0.1 per cent of copper as carbonate re- sulted in badly poisoned plants containing about four times as much copper in root systems as in a lumpy mixture of soil con- taining the same amount of copper. The heavy tailings clay, with which copper is chiefly associated in the district studied, tends to remain in lumps and masses, thus minimizing toxic effects of contained copper compounds. In water cultures toxic effects of copper salts are lessened by salts contained in well-water or in nutrient solutions. This is due, in part, to the presence of other ions, the effect of which is to decrease the ionization of copper salts, with consequent decrease in toxicity. This observation applies to soil-water solutions which contain considerable amounts of alkali salts. It is of interest in this connection to note that certain combinations of salts representing complete mineral nutrients exert maximum antitoxic action to copper salts ;^* and that therefore a fertile soil containing maximum amounts of plant nutrients will tend to minimize toxic effects of copper. Antagonistic solutions, so called, involving copper, may also account for a decrease in toxicity. By reason of a property of the semipermeable membranes of root systems, ions may be either more readily or less readily allowed to penetrate. When pene- tration is decreased through the addition of ions of other soluble salts this salt is said to be antagonistic in character. Copper is thus antagonized by sodium and potassium salts, of which the soluble salt content of the soil is chiefly composed. ^^ 24 A. Le Eenard, Essai sur la valeur antitoxique de 1 'aliment complet et incomplet. Abstracted in Science n. s. vol. 28, no. 712, p. 236, 1908. 25 See Bibliograpliy, p. 237, references 3.5-44, 52. General Discussion 219 Physical attractions, or adsorptive effects, also account for a very considerable lessening of the amount of dissolved copper salts, in contact with soil particles. Jensen, for instance, finds that a dilute copper solution is ten times as toxic in the free con- dition as when it is mixed with an artificial quartz soil, that is to say, the quartz reduces the toxic effects about nine-tenths. In- asmuch as tlie reduction in toxicity is a function of the solid surface to which the soluble salts are exposed, the finer the state of division of a soil tlie more will be the adsorption and the less will be the toxic effects of a stated copper solution.-*' The age of plant roots markedly affects their susceptibility to copper salts. Young and tender roots, containing large amounts of protoplasm, are much more quickly and easily poisoned than old and comparatively fibrous structures contain- ing a small proportion of protoplasmic materials. This may be due to differences in the thickness of cell walls protecting the cell contents from outside substances ; it may be due to a different degree of permeability of the protoplasm of older roots to copper salts; or it may be due to lessened reactivity due to changed chemical character. In any case, this observation indicates a distinctly greater resistance to copper in soils, of older, more fibrous, and possibly intrinsically more resistant root systems. Different species of plants also show varying degrees of resistance to copper salts. In pot cultures, peas are distinctly more re- sistant to precipitated carbonate of copper than corn. Different plants of the same species also show a certain amount of indi- viduality with reference to absorption of copper. Stimulation Not only do the various influences described above lessen the toxic effects of copper upon plants, but it is possible, also, that the amounts of copper may be decreased in the field to the point at which stimulating effects occur. As shown in the dis- cussion of water cultures on preceding pages, extreme dilutions of copper salts in distilled water, for instance, 1 part to 100.- 26 G. H. Jensen, Botanical Gazette, vol. 43, p. 11, Jan., 1907. 220 Bulletin 80 000,000, caused increased growth of root tips growing in these sohitions. This observation accords with those of some other experimenters, not only with copper solutions but with solutions of various other metals, and bears a certain analogy to stimulat- ing effects upon animals observed with very small amounts of poisons, such as arsenic and strychnine. Stimulation was also observed in the case of certain pot cultures watered with dilute copper solution in such a way that these solutions were filtered through a thin layer of soil before they reached the plant roots. Under these conditions a portion of the root systems must come in contact with extremely dilute copper solutions residual from the reactions of copper salts with the soil. As in the case of water cultures, these extremely dilute solutions must have ex- erted the stimulating effects which were apparent in several cultures made in this manner. In the case of pOt cultures also, in which stated amounts of copper were uniformly mixed throughout the soil, apparent stim- ulation of growth was occasionally observed; for instance, with 0.01 per cent of copper in the form of precipitated carbonate in a culture of corn. A satisfactory explanation of stimulation effects is not avail- able. It is to be supposed that stimulation in a soil culture in which copper sulphate is used may be explained by the action of the SO4 ion upon the soil in releasing plant food for the use of the plant. However, such stimulation is seen in water cultures where this does not occur. Lipman-^ has observed that under certain conditions the nitrifying flora of soils is stimulated by salts of copper, zinc, iron and lead. Sach stimulation, through increased elaboration of nitrates, may account for the behavior of cultures showing increased growth. Stimulation effects, there- fore, which undoubtedly occur both in water and in soil cultures, are perhaps due to more than one different cause — to chemical and bacterial agencies in soils, and to a pathological disturbance in water cultures.^^ Taking into account the very minute amounts of copper salts with which stimulated growth is associated, and the very gradual 27 Lipman, C. B., and Burgess, P. S., Univ. Calif. Publ. Agr. Sci., vol. 1, no. 6, pp. 127-139, 1914. 28 See Bibliography, pp. 236-237, references 2, 4, 27, 33, 53, 45. General Discussion 221 addition of copper to new ground that may occur through irri- gating waters, it is not impossible that in favorable situations an actual increase in vegetable growth in the field due to copper may take place ; but it is not possible in the field to prove this supposition because of many other factors, the effects of which prevent trustworthy observation. Field Observations In view of the many factors influencing results in the field, some leading towards toxic copper effects, some opposing toxic effects, and still others pointing to the possibility of stimulated growth, it is of interest, finally, to refer to field conditions as they have existed in irrigated lands under the Clifton-Morenci mines for the twelve years during which the district has been under observation. At the beginning of this period, in 1904, considerable accumulations of copper-bearing tailings were evi- dent, more particularly at the heads of alfalfa fields, where they sometimes attained a thickness of as much as ten inches or more. These blankets usually thinned out and disappeared between 100 and 200 feet from the head ditches, leaving crops in lower por- tions unaffected. Deposits of river sediments were observed in other irrigated districts not affected by mining detritus. The growth of alfalfa was more depreciated by the denser and thicker tailings blankets ; and yellow foliage of young grain and young corn was considerably in evidence in tailings, but not as an effect of ordinary sediments. In 1908, the tailings were impounded, and some of the best farmers began the practice of cultivating alfalfa to break up the old accumulations, incorporate them with the soil, and secure better penetration of water and air to the roots of the crop. Following this procedure the stunted growth at the heads of alfalfa lands has considerably but not yet en- tirely recovered. Patches of yellow young barley, wheat, and oats are still to be observed on old tailings deposits ; but as the plants become older they become normal in appearance, and yield apparently normal crops. These observations, which may be repeated many times in the course of a day's reconnaissance in the district, from May to September for alfalfa, and February 222 Bulletin 80 to May for grain, may be explained by the following consider- ations: The wedge-shaped deposit of tailings indicated in the diagram (fig. 15) at first so obstructed access of water and air to alfalfa root-systems that only stunted development was pos- sible either of roots or tops. With an annual cultivation of this blanket and the incorporation of river sediments and better penetration of irrigating waters, deleterious effects tend to dis- appear and the crop again approaches normal. Similar land when plowed for grain contains most of the copper associated with old tailings at the surface of the soil. Young grain, therefore, with shallow and susceptible root sys- ■yfvx yyjq ?. ;. ■> :^^s-<.- ,■,,.> ■-'- ^ ■"_ .-'.-^•'^^ W'r:/MiM Fig. 15. — Diagram showing behavior of root systems under influence of tailings blanket. tems, at first, if ever, shows effects of copper in the soil, recovering as root systems penetrate to greater depths wliere they encounter uneontaminated soil. Effects of River Sediments With reference to the further trend of copper effects upon vegetation in the district, assuming the permanent exclusion of solid tailings but a constant addition of about one part of copper to one million of irrigating water used, it is of interest to take into account the diluting effect of river sediments upon copper compounds in the district. In four acre-feet of Gila River water, these sediments will amount to about eighty tons per acre a year,--* of which amount the ten pounds of copper contributed in irrigating waters is only 0.006 per cent. 29 Forbes, E. H., Ariz. Agr. Exp. Sta. Bull. 53, p. 61. General Discussion 223 Irrigating sediments alone, therefore, considered in their general relation to amounts of copper which cannot be prevented from reaching irrigated fields, are sufficient in quantity to re- duce ultimately the amounts of copper observed below 0.01 per cent in the soils of this district. Since 0.01 per cent is a safe minimum, river sediments, alone, incorporated with the soil are probably sufficient to ameliorate gradually existing accumula- tions of copper salts and to take care of further contributions in soluble form which cannot at present be avoided. Effect op Cultivation upon Alfalfa Finally, it is of interest to observe the improvement in a field of alfalfa, in the district studied, between the years 1005 and 1916. June 23, 1905, the writer carefully measured, cut and weighed a representative plot of alfalfa in William Gillespie's field near Solomonville, Arizona. This field was suffering from an accu- mulation of tailings, the depreciation in yield at the upper ends of alfalfa lands being conspicuously evident. Following the exclusion of tailings from the irrigating supply in 1908, and with a cultivation each winter with a disk or a spring-tooth harrow, the condition of the field gradually improved until, June 13, 1916, the writer returned and again measured, cut, and weighed the identical plot of alfalfa that had shown bad effects eleven years before. Following are the data, with diagrams, relating to these two cuttings of alfalfa, which are representative for the district within which tailings were deposited. 1. Alfalfa seriously affected by tailings, June 23, 1905. Three lands in William Gillespie's field east of house, near Solomonville, under Montezuma Ditch, out of Gila River. A good stand of alfalfa five years old. Heavy adobe soil ; field never disked. The three lands observed were, over all, 95 feet wide, and divided into plots 100 feet long from top to bottom of field. Ten feet next the ditch was discarded because of banks and bare spots, and the extreme lower portion of the field because of roadways. A portion of plots 6 and 7 was discarded on account of Johnson grass. 224 Bulletin 80 Observations were made June 23, 1905, on the second cutting, just beginning to bloom, the field having been irrigated twice since the last cutting. After stirring and raking, the yield of dry hay was weighed June 24. Weather very hot and dry. Fol- lowing are the data relating to this series : Plot Dimen- sions in feet Height of alfalfa, inches Yield of plot, pounds Tons per acre Depth of tailings on plot, inches Condition of surface soil at time of cutting 1 95x100 19 240 .69* l*-3i Dust-dry and somewhat cracked 2 95x100 20 340 .87* 1 -2 Dry and badly cracked 3 95x100 23-25 570 1.31 ?-u Dry, cracked at upper end 4 95x100 24 595 1.36 1-1 Moist, not cracked 5 95x100 23 550 1.26 3-1 Moist, not cracked 6 60x100 28 400 1.41* 2-1 Moist, not cracked 7 60x100 27 430 1.48* i- h Moist, not cracked Corrected for thin stand and trash. 2. Alfalfa slightly affected hy tailings, June 13, 1916. The same three lands, continuously in alfalfa since 1905. A perfect stand, thin spots reseeded by means of a seed crop in 1915. The field had been spring-tooth harrowed each winter for about ten years, especially at heads of lands, to break up the tailings blanket and secure better penetration of irrigating water. As in 1905, ten feet next the ditch Avas discarded, also the extreme lower portion of tlie field. Johnson grass had nearly entirely disappeared. Observations were made June 13, 1916, on the second cutting, just beginning to bloom, the field having been irrigated twice since the last cutting. After raking and piling, the dry hay was hauled and weighed June 17. The weather was moderately hot and dry; and conditions generally the same as those under which the crop was cut in 1905. Following are the data for the second series of observations: General Discussion 225 Plot 1 Dimen- sions in feet 95x100 Height alfalfa, inches 36-21 Yield of plot, pounds 875 Tons per acre 2.00 Appearance of tailings Distinct Condition of soil at time of cutting Surface dusty, drier soil 2 95x100 22-34 857 1.96 Distinct Surface dusty, drier soil 3 95x100 34-36 972 2.22 Slight Moist throughout 4 95x100 30-36 910 2.08 None Moist throughout 5 95x100 31-33 900 2.05 None Moist throughout 6 95x100 28-36 860 1.96 None Moist throughout 7 95x100 34-37 870 1.98 None Moist throughout 8 95x100 33-36 910 2.08 None Moist throughout Comparing these two statements, and illustrating them by means of the following diagram (fig. 16), it is evident that the depreciation in yield observed in the upper plots in 1905 has dis. appeared in 1916, the yields on the last date being practically uniform from top to bottom of the field. Effects of tailings are still plainly visible in plots 1 and 2 in spots and patches of short alfalfa, compensated for, however, by areas of stimulated growth apparently due to seepage from the adjacent ditch. The yield of the field as a whole is also much improved due to cultivation and reseeding of the field. In brief it may now be stated that, following the exclusion of tailings from the irrigating waters of this locality, it has been found possible, in this carefully observed case, to overcome the deleterious effects of tailings deposits upon alfalfa, slowly but almost entirely, in about ten years. Thus, co-operation between miners, in restraining tailings from irrigating streams, and those farmers who cultivate their alfalfa intelligently, effectually disposes of the most serious prob- lem that has arisen in connection with copper-mining detritus. ■ The chemical composition of tailings, in fact, would indicate that, as in the case of humid region subsoils, when they are en- riched by the addition of organic matter and nitrogen, and filled with bacterial life, they may make very good soil. Following is a statement of the composition of four representative samples of ores and tailings, with reference to potash and phosphoric acid : 226 Bulletin 80 aavDsiQ H 00 o oa 00 H CO cr t- H CO cr to cr CD co* H LU lO z o D OJ 00 ^ in H _i n H < CO L. o -J CsJ < ■* s c^t z »2 "" ■ t aavasiQ 1 L L 1 — ^ooocjoooopoo X O on CO ■^ - ^ CO C\J lij H z CO 1- lO u o _l fl H < _1 to CO < ^^ u. -"t u. o a _i !-■ UJ >= CO CO -Sb H t^ ^ 00 c cJ u E w < <^ £ CX)CL V) z H — ^ r t oavosiQ L L 1 1 m ^ S « ^ « o *2 ^ •M ^ ^ ■Vl ^ O 00 o T) Oi I-H a> « <1) o 0) ji HOXIQ Su: MMARY 227 Sample No. 3491 Sulphide ore Potash K.O .64% Phosphoric acid P.O. .11% 'Nitrogen N Doubtful 3492 Oxidized ore .44 .11 3438 Sulphide tailings .79 .29 traces 3439 Oxidized tailings .67 .12 These ores and the tailings derived from them are rich in potash, and contain unexpectedly large amounts of phosphoric acid; but nitrogen is almost nil. SUMMARY 1. Copper is shown, as a direct effect of the Clifton-Morenci mining operations in Arizona, to be distributed throughout water- supplies, soils, the vegetable and the animal life of an under- lying irrigated district. 2. Smaller amounts of copper are found elsewhere in the State where the drainage basin includes mining operations or ore-bearing areas. 3. Individual plants grown in water cultures or in soil con- taining copper show a comparatively small, and probably not injurious, accumulation of copper in the aerial portions of the plants; but the root systems, carefully cleansed of externally adhering copper, contain relatively great amounts." 4. Copper in root systems, as shown by the biuret test, is largely in combination with plant proteids, especially at the growing points of root systems and near vicinity. The place and nature of the reaction accounts for the extreme toxicity of copper .salts to plants. The varying sensitiveness of plants to copper salts may possibly be explained in part by the number and disposition of exposed growing points. 5. Conditions favoring toxicity of copper compounds are the presence of carbon dioxide and certain soluble salts which assist in forming copper solutions that come into contact with plant roots ; coarse, sandy soils favoring free access of copper solutions to plant roots and minimizing the withdrawal of copper from solution by adsorption ; and the presence of copper in the form of the more soluble precipitated carbonate. 228 Bulletin 80 6. Conditions opposing toxicity of copper compounds are the presence of copper in the form of chrysocolla and chalcocite ; adsorption through contact with finely divided soil particles ; reactions with carbonates, silicates, and organic matter tending to precipitate copper from its solutions; the presence of certain soluble salts in the soil that overcome toxic action ; and increased resistance of old plant roots. 7. The stimulation by copper of vegetative growtJi in pot and water cultures has been observed. Stimulated growth of crops under field conditions is a possibility. 8. Pot cultures may be used for comparative determinations of toxic effects upon plants of copper in soils, if conducted under rigidly uniform conditions. The copper content and the physio- logical response to copper of such material will be much greater than for similar cultures grown under plot or field conditions. 9. Copper injury in field soils containing doubtfully toxic amounts of copper may be diagnosed by a combination of symp- toms. Facts which indicate such injury in a soil containing 0.1 per cent of copper (more or less) are: yellow tops (for winter grains) in absence of other conditions that cause yellow tops; crinkly root systems (in absence of excessive amounts of alkali salts) ; and a high copper content in dry matter of root systems. Combined evidence of this character, which may be observed in the district studied, indicates toxic copper effects. 10. Field observations before and following the exclusion of tailings from the irrigating water-supply indicate that conditions in the district studied are gradually improving, due to the culti- vation of alfalfa and to the incorporation of river sediments witli accumulations of tailings. Noticeable toxic effects in the field exist only where the roots of young, growing crops are exposed to surface soils containing maximum amounts of copper. The general tendency in the district is probably toward decreasing rather than increasing percentages of copper in irrigated soils. 11. Methods of analysis have been developed for the purpose of determining reliably small amounts of copper in vegetative material, particularly- in root systems of plants grown in soils containing copper. Methods of Analysis 229 Part III.- APPENDIX METHODS OF ANALYSIS With the Collaboration of E. E. Free and Dr. W. H. Ross Freedom of samples, especially vegetation, from contamina- tion with adhering copper ; and accurate methods for determin- ing minute amounts of copper in sediments, soils, waters and vegetation, are vital to the integrity of the work recorded in this publication. Unusual care was taken to perfect methods for preparation of samples, especially roots grown in media containing copper; and refined manipulation in the determination of copper reduced the limit of error to approximately .00001 gram, or .01 milligram. Reagents and Apparatus Distilled ivater of three derivations was used: (1) University of Arizona well water very slowly distilled through a block-tin worm; (2) the same, redistilled from glass; and (3) University of Arizona well water distilled from glass. Nitric and sulphuric acids from Baker & Adamson were used. Ammonia and H.S employed were passed through two wash bottles. Blank determinations from time to time with reagents em- ployed gave no trace of copper, thus insuring results obtained by means of them. Copper was determined by electrolysis, in minute amounts according to the manipulation of E. E. Free.^ The balance used was a No. 2112 Eimer and Amend short- beam assay balance, "distinctly. sensitive to 1/200 milligram." Manipulation Ores and tailings. — 1-2 gms. were digested with a mixture of 8 c.c. HNO, and 5 c.c. HCl on a hot plate, then 4 c.c. HoSO^ added and evaporated to HoSO^ fumes (method used in Old Dominion laboratory at Globe, 'and Copper Queen at Bisbee). Took up with water, filtered, neutralized with ammonia, then added 2 c.c. H2SO4 and a few drops of ITNO.^ and electrolyzed. Soils. — Soils were examined by two methods : (a) 100 gms. soil was treated with a mixture of 80 c.c. HNO, and 20 c.c. H.SO^ and digested in a porcelain disli on a hot plate to sulphuric fumes ; digested with 200 c.c. water, filtered, washed up to about 500 c.c, evaporated to 200 c.c. precipitated iron with ammonia, filtered, washed with about 500 c.c. water, alkaline filtrate reduced by evaporation, acidified faintly with HCl and H,S passed for half an hour. The faint black precipitate was 1 Electrolytic determination of minute quantities of copper, 12th Gen. meeting Am." Electroehem. Soc, October 17-19, 1907. 230 Bulletin 80 allowed to settle several hours, then filtered, and the precipitate, including filter, digested with 5-10 c.c. HNO3 and water until copper was dissolved, solution filtered, a few drops of HoSO^ added, evaporated to fumes, and copper determined by elec- trolysis with addition of 5-25 drops of HNO,. (h) 200 gms. soil was digested as above with HNO3 and H2SO4, evaporated to fumes of H2SO4, digested with water, filtered and washed up to 500 c.c, made alkaline with ammonia and made up to 1000 c.c. After settling, 500 c.c. or 100 gms. aliquot, was filtered off and copper determined as in (a). Waters. — Waters were evaporated to dryness, the residue digested with sulphuric acid and water, filtered hot, excess of H2SO4 evaporated, filtered into platinum dish, a few drops of HNO3 added, and electrolyzed. Vegetation. — Air-dried samples were burned in a small sheet- iron stove, the iron of which was found to contain no trace of copper. Two samples of mistletoe, difficult to burn, were reduced in a new muffle in gasoline assay furnace. The charred and partly burned material was moistened with water, and concen- trated HNO3 added (100 to 200 c.c.) until effervescence ceased, digested until in plastic condition, diluted with hot water and filtered. Evaporated bulky filtrate to dryness, took up with water and HNO3, filtered (getting rid of much organic matter), added about 20 c.c. HoSO^, evaporated to HoSO^ fumes, driving off all but about 5 c.c. H2SO4, added water, filtered off' insolubles, made up filtrate to about 500 c.c, passed H2S, and proceeded as usual for copper. The completeness of the extraction of copper from vegetation by the above method was verified as follows: The extracted, charred residue from 2 lb. 8 oz. of dry corn leaves and blooms in which 1.32 parts Cu per million was found (Sample 3529) was removed from filter paper after washing, moistened with H2SO4 and additionally burned in a porcelain dish, being finally reduced, after again moistening with H2SO4, in a platinum dish in the muffle. The resulting pink ash was then fused with three parts of dry NaoCO. (Kahlbaum) and poured on clean porcelain. The fusion was soaked in water with addition of H0SO4, evapor- ated nearly to dryness, filtered from insoluble portion (lime, salts, etc.), again evaporated and filtered, and a third time the same, finally driving off excess of HsSOj and electrolyzing as usual. A black precipitate of carbon but no Cu was obtained, the same being true of a blank determination on the NaoCOs used. Roots of plants gi-own in water cultures or in soils must be most thoroughly cleansed of externally adhering copper, since this will introduce excessive errors where the content of copper is small. Three methods of preparing roots for copper determina- tion were employed : 1. Roots grown in water cultures containing copper were dipped for about ten seconds in 4 per cent HCl, immediately Methods of Analysis 231 washed in copper'-free water and dried. Careful observation in- dicated that adhering copper salts deposited from water solution were completely removed by this treatment. ■ It is probable that the acid penetrates plant tissues somewhat in the time employed and removes some copper. The results are, therefore, probably severely conservative. 2. Roots grown in soil cultures containing copper cannot be safely cleansed with HCl, which does not readily dissolve silicates and sulphides of copper, and which cannot be allowed to remain in contact with plant' roots for more than a few seconds. Carbon dioxide in water was finally selected as a mild, slow but finally effective solvent for the purpose. Samples of roots were first very thoroughly washed in copper-free well-water, then placed in five-liter jars with ground glass covers, a stream of washed CO, passed, the jars shaken and treatment with COo repeated until the water was saturated, then allowed to stand with occasional shaking for twenty-four hours. The solution was then siphoned or filtered off and the treatment repeated until, on evaporating the bulky filtrates, no more copper was found. To prevent putrefaction during long-continued washings, a pinch of thymol w^as added to each washing. From nine to thirty-one washings were found necessary to cleanse plant roots thoroughly, the process being laborious and time-consuming. When the sample yielded no more copper to wash waters it was dried, burned and copper determined according to the method for small amounts in plant ashes. Following is a record of washings for examples of roots cleaned by this process: (1) Corn roots grown in a pot culture of soil containing 0.01 per cent of copper as basic carbonate. Quantitative by ^2^* *^^* electrolysis First wash distinct Fifth wash distinct Ninth wash doubtful 1 liter of filtrate no Cu (2) Corn roots grown in a pot culture of soil containing 0.05 per cent copper as Cu.,S. Quantitative by electrolysis Tenth wash 2 litres o f filtrate .00006 gm. Cu (3) Barley roots from field soil containing tailings. Quantitative by electrolysis First wash 2.433 litres of filtrate .00035 gm. Cu Second wash 2.531 .00012 Fifth wash 2.22 .00000 Sixth wash 2.41 -.00004 Seventh wash 2.00 .00002 Eleventh wash 2.00 .00000 232 Bulletin 80 (4) Coarse roots of field corn grown in soil containing tail- ings. HjS test Quantitative by electrolysis Twenty-fifth wash distinct Twentv-ninth wash .00005 gm. Cu Thirty-first wash .00000 Samples vary as to number of washings required to remove the last trace of copper, but the definiteness with wiiich, finally, copper usually ceases to be extracted by CO, water indicates completeness of the operation. This is further emphasized by the comparatively large amounts of copper which are then found in root systems thus cleansed. 3. A third method of preparing roots for copper determin- ation, involving less labor than by washing in CO^, water, is as follows: Cleanse roots thoroughly in clean water with a camel- hair brush, dry, burn and weigh the ash, then estimate total copper. Determine copper in soil shaken from sample, assume ash as all soil and deduct copper in this amount of soil from total copper found in ash. Results by this method are low, but not seriously in error if sample is thoroughly washed. Pts. Cu Dry per Example matter Ash Gms. Cu million Sample 2a! grown in soil containing 0.05% copper .3561 gm. 10.84% .000115 322 Ash in sample .0386 Copper in ash as- sumed as soil .000019 Net copper assumed .000096 270 The correction introduced reduces parts per million of copper from 322 to 270, which latter figure is conservative in character. Of the three methods above described. No. 2 is undoubtedly most exact, but is extremely laborious and time-consuming. THE DETEEMINATION OF COPPEE IN SMALL AMOUNTS OF PLANT ASHES The ash is placed in a platinum dish without previous pulver- ization and moistened with concentrated sulphuric acid in suf- ficient quantity to bring all parts of the ash in intimate contact with the acid. The material is then thoroughly stirred and heated on a sand bath until fumes of SO,, begin to come off, then allowed to cool and a sufficient quantity of hydrofluoric acid added to bring the acid in contact with the whole mass, then allowed to stand for at least half an hour and again heated until Methods of Analysis 233 SO., fumes come off. The material is now washed into a casserole, moistened witli sulphuric and nitric acids and digested at a low heat for at least one hour. The heat is then increased until SO;, fumes are again driven off. The mass is moistened with three to four times its bulk of distilled water and digested at a gentle heat from one to two hours, filtered hot and then tlie fil- trate and washings evaporated almost to dryness, thus driving off the excess of sulphuric acid. The resulting residue is taken up with hot water and again filtered to separate the solution from precipitated calcium sulphate. This evaporation and filtration may have to be repeated one, two or three times in order to get the solution sufficiently free from calcium sulphate. The final filtrate, which contains the copper, is then diluted to about 150 to 200 c.c. in a tall beaker, a small quantity of hydrochloric acid is added and hydrogen sulphide passed until the solution is thoroughly saturated. During the hydrogen sulphide precipi- tation there should be no nitric acid or nitrates present in the solution. A large quantity of organic matter is also disadvan- tageous and may be avoided by evaporating the solution several times to dryness with nitric and sulphuric acids, finishing finally witli an evaporation with sulphuric acid alone in order to drive oft' all tracts of nitric acid. The precipitate from the treatment with hydrogen sulphide is filtered off, washed with water saturated Avith hydrogen sulphide and digested with a small quantity (2 to 5 c.c.) of nitric acid in a casserole. The digestion should be begun cold and the heat gradually increased. If the digestion is begun at a high tempera- ture the sulphur formed by the decomposition of the copper sulphide will form a film of molten sulphur around the' granules of copper sulphide, and this tends to prevent their solution in nitric acid. The precipitate after digestion in nitric acid should be a clear green or else a yellow. If tliere is any trace of dark color, brown or black, it means that either organic matter has been precipitated with the copper sulphide precipitate, which is extremely unlikely, or else that the above-mentioned sulphur film lias formed around some of the particles of copper sulphide preventing their solution in the nitric acid. If the latter be the case, the determination ma.y still be saved by placing the precipitate in a platinum dish and heating over a gentle flame until the sulphur is volatilized. The residue of copper .sulphide or of copper oxide may then be digested in nitric acid. The digestions in nitric acid should not be carried to a heat high enough to decompose the copper nitrate formed by the solution of copper sulphide. After digestion in nitric acid and the evaporation of any large excess of nitric acid, the residue is taken up in hot water, acidified to contain 2-4 per cent nitric acid and filtered into a large platinum dish, i^ to I/2 c.c. of sulphuric acid is added, and the solution electrolyzed with a voltage of from 2 to 21/) 234 Bulletin 80. volts and a current not greater than one ampere. The voltage may be higher than 21/0 volts if necessary but should not be high enough to raise the ciirrent beyond the limit given. The elec- trolysis should be continued at least three hours and preferably nine to twelve hours. The dish is, of course, the cathode. Wlien the electrolysis is complete the electrolyte is washed out of the dish by means of the sucking-bottle and the dish is thoroughly washed with distilled water. In case the deposit of copper on the dish is spongy and loosely adherent it is not safe to wash out the electrolyte. In this case the copper should be redissolved and the electrolysis repeated, using a little more sulphuric acid. If the copper still refuses to come down in adherent form the addition of 2 to 5 c.c. of a one per cent solution of gelatine will often assist the precipitation. In case of a stubborn refusal of the copper to give an adherent deposit it is necessary to dissolve it, evaporate to dryness with sulphuric acid, and reprecipitate with hydrogen sulphide, continuing the process from this point as before. If the copper refuses to come down at all the trouble is probably an excess of acid in the solution. This may be corrected by the addition of a few drops of ammonia. The concentration of acid in the solution nuist lie between one and five per cent. At least a small part of this should be sulphuric acid as nitric acid will be destroyed in the course of the electrolysis if it alone is present, and the solution may become alkaline (from NH^OH), which will prevent proper precipitation. Chlorides and organic salts, such as acetates and tartrates, should be carefully avoided. The resulting deposit of copper will probably contain traces of carbon and possibly of platinum. In order to eliminate these and at the same time precipitate copper upon an electrode more suitable for accurate weighing, a second electrolysis is made, using this time the dish as anode and using as cathode a small spiral of platinum wire suspended from a hook of silver (or platinum) wire which in turn is connected to the battery. The electrolysis should also be conducted in nitric and sulphuric acid solution and what is said above as to obtaining satisfactory deposits applies with equal force here. In this case, however, owing to the small surface area of the cathode, it is necessary to work with very much smarller currents than were used in tlie first electrolysis. The maximum current to be used must be so adjusted by trial as to give bright and adherent deposits. 1-lOOth ampere and 1.8 volts is a good current for the purpose. It is well to use as the source of current for this electrolysis four Edison- Lalande cells and to have in the circuit a resistance of from 30 to 80 ohms. This gives an electromotive force at the dish of about 1.8 volts. Two determinations may be run in parallel. In this case it is not permissible to use a gelatine solution in order to secure satisfactory deposits, as the copper will be slightly contam- inated with gelatine and the obtained weight will be too high. Methods of Analysis 235 The electrolysis should be run at least nine hours. "When com- pleted, the electrolyte should be washed out as before without breaking the cui'rent, the electrode lifted from the solution, dis- engaged from the supporting hook, and washed and dried by dipping successively in water, alcohol and ether and placing in a desiccator over sulphuric acid. After having remained in the desiccator for an hour the electrode is ready for weighing. Weighings should be made on an assay (button) balance adjusted to maximum sensibility. After weighing, the copper is removed from the electrode by dipping in concentrated nitric acid, and the electrode cleaned and dried by dipping successively in dis- tilled water, alcohol and ether and placing in a desiccator. It is again weighed as before and the difference of the two weights gives the copper obtained. The electrolyte (from each electrolysis) which has been washed out of the dish by means of the suction flask, is evapor- ated to dryness taken up with water, acidified with nitrie acid and tested for copper by electrolyzing, using the point of platinum wire as cathode. In this way any possible loss of copper by incomplete precipitation in either of the electrolyses is prevented. If any copper is found in this check test it should be dissolved from the platinum wire, added to the solution ob- tained by dissolving the copper from the small electrode, and the electrolysis repeated in order to get the true weight. In case a quantity of copper too small to be weighed is obtained its identity as copper may be most easily established by electrolyzing it onto the point of a platinum wire as described above. In these electrolyses with the platinum wire as cathode the current must, of course, be kept low in order to obtain satis- factory deposits. If this precaution is observed the deposit on the platinum wire will be of a brilliant red color and easily dis- tinguishable as copper. If the deposit is brownish or blackish its identity as copper may be established by the green flash when the point of the wire is held in the colorless flame of the Bunsen burner, particularly if the wire has been first dipped in hydro- chloric acid. Nitric acid must not be used, as nitric acid itself will give a green flash in the Bunsen burner flame. The reagents used in the above process should all be tested as to freedom from copper. The water used should be doubly distilled and, at least the second time, from glass. All utensils should be cleaned by boiling in nitric acid. Care must also be taken to conduct the operations in rooms free from dust which might possibly contain copper. 236 Bulletin 80 BIBLIOGRAPHY 1 Aderhold, R., Zur Frage der Wirkung des Kupfers auf die Pflanze. Ber. deut. bot. Ges., vol. 24, p. 112, 1898. 2 Bain, S. M., The action of copper on leaves, Tenn. Agr. Exp. Sta., vol. 15, Bull. 2, 1902. 3 Barker, B. T. P., and Gimingham, C. T., The action of Bordeaux mixture on plants, Ann. Appl. Biol., vol. 1, no. 1, pp. 9-21, May, 1914. i Brenehley, W. E., Influence of copper sulphate and manganese sul- phate upon the growth of barley, Ann. Bot., vol. 24, no. 95, p. 571, 1910. 5 Brenehley, W. E., Inorganic plant poisons and stimulants, pp. 15-35. (1914.) 6 Burrill, T. J., Effect of copper on bitter-rot spores, Illinois Exp. Sta. Bull. 118, p. 569, Sept., 1907. 7 Clark, H. W., and Gage, S. DeM., On the bactericidal action of copper. Jour. Infect. Dis., Supplement no. 2, Feb., 1906. 8 Collier, Peter, Influence of copper compounds in soils ujiou vege- tation, N. Y. Agr. Exp. Sta. Bull. 41, pp. 35-43, April, 1892. 9 Coupin, H., Sur la toxicite des sels de cuivre a I'egard des vegetaux superieurs, Compt. rend., Acad. Sci., vol. XCCVII, p. 400, 1898. loDevaux, H., Fixation of metals by cell membrane (Tr.), ibid., vol. 138, p. 58, 1901. 11 Ewert, Dr., A chemical-physiological method for determining small amounts of copper in extreme dilution (Tr.), Zeitsch. f. Pflanzenkrankh., vol. 14, p. 135, 1904. 12 Free, E. E., The solubility of precipitated basic copper carbonate in solutions of carbon dioxide. Jour. Am. Chem. Soc, vol. 30, no. 9, p. 1366, Sept., 1908. 13 Free, E. E., The electrolytic determination of minute quantities of copper, Proc. Am. Electrochem. Soc, Oct. 17-19, 1907. 1* Freytag, Dr., Die schadliche Bostandtheile des Huttenrauchs der Kup- fer- Blei- und Zink-Hutten und ihre Beseitigung, Landw. Jahrb., vol. 11. 1882. 15 Haselhoff, E., Concerning the injurious effect of water containing copper sulphate and copper nitrate upon soil and plants (Tr.), Landw. Jahrb., vol. 21, p. 263, 1892. 16 Hattori, H., Studies upon the effect of copper sulphate upon certain plants, Jour. Coll. Sci., Univ. Tokio, vol. 15, pt. Ill, 1901. 1' Haywood, J. K., Injury to vegetation and animal life by smelter wastes, U. S. D. A., Bur. Chem. Bull. 113 (revised), July, 1910. 18 Jensen, G. H., Toxic limits and stimulation effects of some salts and poisons in wheat, Bot. Gaz., vol. 43, p. 11, Jan., 1907. 19 Kirchner, O., tJber die Beeinflussung der Assimilationstatigkeit von Kartoffelpflanzen durch Bespritzung mit Kupfervitriol Kalkbriihe, Zeitschr. f. Pflanzenkrankh., vol. 18, Heft 2, p. 65, 1908. 2oKraeiner, Henry, The copper treatment of water. Am. Jour. Pharm., voh 76, no. 12, p. 574, Dec, 1904. 21 Kraemer, Henry, The use of metallic copper for the purification of drinking water, Und., vol. 78, no. 3, p. 140, March, 1906. 22 Kraemer, Henry, The use of copper in destroying typhoid organisms, and the effects of copper on man, ibid., vol. 77, no. 6, p. 265, June, 1905. 23 Lehmann, H. B., Der Kupfergehalt von Pflanzen und Thieren in kupferreichen Gegenden, Archiv. fiir Hygiene, vol. 27, p. 1, 1896. 24Lipman, C."B., and Wilson, F. H., Toxic inorganic salts and acids as affecting plant growth, Bot. Gaz, vol. 55, no. 6, ]>. 409, 1913. Bibliography 237 2s LiiMiian, C. B., and Burgess, P. S., The effect of copper, zinc, iron and lead salts on ammonification and nitrification in soils, Univ. Calif. Publ. Agr. Sci., vol. 1, no. 6, pp. 127-139, March, 1914. 27 Livingston, B. E., Chemical stimulation of a green alga, Contr. N. Y. Bot. Garden, no. 63, 1905. 28 Long, J. H., The physiological significance of some substances used in the preservation of food, Science, n.s., vol. 37, no. 950, p. 401, March, 1913. 29 Luckey, Use of copper sulphate in fertilizer, U. S. P. 838036, 1906. 30 Miani, D., Uber die Einwirkung von Kupfer auf des Wachsthum lebender Pflanzenzellen, Ber. deutsch Bot. Ges., vol. 19, p. 461, 1901. 31 Michigan Acad. Sci., The toxic action of copper sulphate upon cer- tain algae in the presence of foreign substances. Seventh Eeport, p. 48, 1905. 32 Moore, Geo. T., and Kellerman, Karl F., A method of destroying or preventing the growth of algae and certain pathogenic bacteria in water supplies, U. S. D. A., Bur. PI. Ind., Bull. 64, May, 1904. 33 Ono, H., tJber die Wachsthumsbeschleunigung einiger Algen und Pilze durch chemische Eeize, Jour. Coll. Sci. Univ. Tokio, vol. 13, p. 141, 1900. 3* Otto, E., Investigations concerning the behavior of plant roots towards solutions of copper salts (Tr.), Zeitschr. f. Pflanzenkrankh., Bd. 3, 1893. 35 Osterhout, W. J. V., The decrease of permeability due to certain bivalentitetions, Bot. Gaz., vol. 59, no. 4, p. 317, April, 1915. 36 Osterhout, W. J. V., Extreme alterations of permeability without injury, ibid., vol. 59, no. 3, p. 242. 37 Osterhout, W. J. V., Protoplasmic contractions resembling plas- molysis which are caused by pure distilled water, ibid., vol. 55, no. 6, p. 446, June, 1913. 38 Osterhout, W. J. V., Quantitative researches on the permeability of plant cells. Plant World, vol. 16, p. 129, May, 1913. 39 Osterhout, W. J. V., Permeability of protoplasm to ions and the theory of antagonism. ■10 Osterhout, W. J. V., On the nature of antagonism, Science, n.s., vol. 42, no. 1050, p. 255, February, 1915. 41 Osterhout, W. J. V., Extreme toxicity of sodium chloride and its. prevention by other salts, Jour. Biol. Chem., p. 363, March, 1906. *2 Osterhout, W. J. V., Plants which require sodium, Bot. Gaz., vol. 54, no. 6, p. 532, December, 1912. 43 Osterhout, W. J. V., Organization of the cell with respect to per- meability. Science, n.s., vol. 38, no. 977, p. 408, September, 1913. 44 Osterhout, W. J. V., Vitality and injury as quantitative concep- tions, ibid., vol. 40, no. 1031, p. 488, October, 1914. 45 Porchet, F., and Chouard, E., De 1 'action des sels de cuivre sur les vegetaux, Bull, de la Muriethienne, vol. 33, 1905. 46 Phillips, F. C, Absorption of metallic oxides by plants, Chem. News, vol. 46, p. 224, March, 1882. 47 Eeed, H. S., Abstract of Essai sur le valeur antitoxique de 1 'aliment coniplet et incomplet, bv A. Le Eenard, Science, n.s., vol. 28, no. 712, August, 1908. 48 Eitthausen, H., Verbindungen der Proteinstoffe mit Kupferoxyd, Jour, f. prakt. Chem., Bd. 5, p. 215, 1872. 49 Eitthausen, H., Verbindungen der EiAveisskorper mit Kupferoxyd, ibid., Bd. 7, p. 361, 1873. 50 Eumm, Ueber die Wirkuug der Kupferpraparate, etc., Ber. deut. Bot. Ges., vol. 11, p. 79, 1893. 51 Schander, E., Ueber die physiologische WJirkung der Kupfervitriol Kalkbriihe, Landw. Jahrb., vol. 33, p. 517, 1904. 52 Stiles and Jorgensen, I., Studies in permeability, Ann. Bot., vol. 29, no. 115, p. 349, July, 1915. 238 Bulletin 80 53 Stockberger, W. W., Effect of some toxic solutions on mitosis, Bot. Gaz., vol. 49, p. 416, June, 1910. 54 Sullivan, E. C, Precipitation of natural silicates, Econ. Geol., vol. 1, no. 1, p. 67, 1907. ■>■> Vedrodi, V., Der Kupfer als Bestandtheil der Sandboden und unserer Kulturpflanzen, Cliem. Zeitung, vol. 17, p. 1932, December, 1893. 56 Viala, On the action of certain toxic substances upon the vine (Tr.), Eevue de Viticulture, nos. 3 and 5, 1894. 57 Spaeth, E. A., The vital equilibrium. Science, n. s., vol. 43, no. 1110, p. 502, April, 1916. University of Arizona Agricultural Experiment Station Twenty-Seventh Annual Report For the Year Ending June 30, 1916 (With subsequent Items) Consisting of reports relating to Administration, Agronomy, Botany, Plant Breeding, Horticulture, Animal Husbandry, Entomology, Chemistry, Irrigation Investigations, and The Weather And Including a report on AGRICULTURAL EDUCATION Tucson, Arizona, December 31, 1916 University of Arizona Agricultural Experiment Station Twenty-Seventh Annual Report For the Year Ending June 30, 1916 (With subsequent items) Consisting of reports relating to - • **' Administration, Agronomy, Botany, Plant Breeding, Horticulture, Animal Husbandry, Entomology, Chemistry, Irrigation Investigations, and The Weather And including a report on AGRICULTURAL EDUCATION Tucson, Arizona, December 31, 1916 UNIVERSITY OF ARIZONA AGRICULTURAL EXPERIMENT STATION GOVERNING BOARD (Regents of the University) Ex-Officio His Excellency, The Governor of Arizona The State Superintendent of Public Instruction appointed by the governor of the state Frank H. Hereford Chancellor William V. WhitmorE, A. M., M. D Treasurer William J. Bryan, Jr., A. B Secretary Lewis D. Ricketts, Ph. D Regent William Scarlett, A. B., B. D Regent Roderick D. Kennedy, M. D Regent Rudolph Rasmessen Regent Frank J. Duffy Regent RuFus B. VON KlEinSmid, a. M., So. D President of the University AGRICULTURAL STAFF Robert H. Forbes, Ph. D Dean and Director John J. ThornbER, A. M Botanist Albert E. Vinson, Ph. D Biochemist Clifford N. Catlin, A. M Assistant Chemist George E. P. Smith, C. E Irrigation Engineer Arthur L. EngER, C. E Assistant Engineer George F. Freeman, B. S Plant Breeder Walker E. Bryan, M. S Assistant Plant Breeder Stephen B. Johnson, B. S Assistant Horticuhurist Richard H. Williams, Ph. D Animal Husbandman Walter S. Cunningham, B. S Assistant Animal Husbandman John F. Nicholson, M. S Agronomist Herman C. Heard, B. S. Agr Assistant Agronomist Austin W. Morrill, Ph. D Consulting Entomologist EsTES P. Taylor, B. S. Agr Director Extension Service George W. Barnes, B. S. Agr Livestock Specialist, Extension Service L S Parke, B. S Boys and Girls State Club Agent Edith C. Salisbury, B. D. S Home Economics Specialist Arthur L. Paschall, B. S. Agr County Agent, Cochise County Charles R. FillErup. D. B County Agent, Navajo-Apache Counties Alando B. Ballantyne, B. S County Agent, Graham-Greenlee Counties John R. TowlES Secretary Extension Service Frances M. Wells Secretary, Agricultural Experiment Station The Experiment Station offices and laboratories are located in the University buildings at Tucson. The new Experiment Station Farm is situated one mile west of Mesa, Arizona. The date palm orchards are three miles south of Tempe (cooperative, U. S. D. A.), and one mile southwest of Yuma, Arizona, respec- tively. The experimental dry-farms are near Cochise and Prescott, Arizona. Visitors are cordially invited, and correspondence receives careful attention. The Bulletins, Time'lv Hints, and Reports of this Station will be sent free to all who apply. Kindlv notify us of errors or changes in address, and send in the names of your neighbors,' especially recent arrivals, who may find our publi- cations useful. Address, THE EXPERIMENT STATION, Tucson, Arizona. LETTER OF TRANSMITTAL To His Excellency, The Governor of Arizona, Bxecntive Department, Phoenix, Arizona. Sir: I have the honor herewith to transmit to you the Twenty- seventh Annual Report of the Arizona AgricuUural Experiment Sta- tion, of the College of Agriculture, University of Arizona, for the fiscal year ending June 30, 1916. This report is made in accordance with the Act of Congress, ap- proved March 2. 1887, establishing Agricultural Experiment Stations, and the Act of Congress, approved March 16, 1906, known as the Adams Act. Faithfully yours, R. B. VON Kli^inSmid, President. President R. B. von KleinSniid, University of Arizona, Tucson, Arizona. Dear Sir: I submit herewith the Twenty-seventh Annual Re- port of the Agricultural Experiment Station for the fiscal year ending June 30, 1916, with subsec[uent items. This report relates to the administration of the Station and to the work in Agronomy, Botany, Plant Breeding. Horticulture, Animal Husbandry, Entomology, Chemistry, Irrigation Investigations, and the Weather: and includes a chapter on Agricultural Education. Very truly yours, R. H. Forbes, Dean and Director. CONTENTS PACe Administration 239 The experimental field 240 General progress for the year 242 The Salt River Valley Farm 242 The Yuma Date Orchard 244 The Tempe Date Orchard 244 Tl\e dry-farms 245 The Northern Arizona Dry-farm 246 Requirements for future progress 246 Personnel 247 Publications 248 Financial 249 Agronomy 251 Phoenix Farm 251 Crops grown 251 The new Experiment Station Farm, near Mesa 258 The Johnson grass experiment 258 Wheat and alfalfa 260 Prescott Dry-farm 263 Crops 264 Silos 265 General conclusions 265 Sulphur Spring Valley Dry-farm 266 Water supply 266 Crops " 266 Conclusions 269 Botany 270 Root-rot disease 270 Publications 271 Studies in the flora 273 Miscellaneous 274 Horticulture 275 Work with lettuce 275 Arizona climate and bean anthracnose 276 Storage of sweet potatoes 277 Keeping eggplant 277 Plant Breeding 278 Wheat 278 Alfalfa 279 Grain sorghums 280 Animal Husbandry 281 Sheep investigations 281 Feeding 'Tepary beans to hogs 286 Effect of rolled barley on alfalfa-beet pulp ration for milk production 288 Ostrich investigations 290 Instruction and executive work 293 Entomology 294 Chemistry 296 Salton Sea water 297 Caliche 298 Plant stimulation with non-essential elements 300 Changes in chemical character of the Tempe Drainage ditch water. . . 300 Miscellaneous 301 Irrigation investigations 303 Casa Grande Valley 303 The Antelope Valley 304 Transpiration studies 305 Station pumping plants 305 Test of pumping plant 307 Guarantees for pumping machinery 308 Concrete water and oij tanks 308 Additional field at University Farm 309 Irrigation conference 310 Silo at University Farm 310 The Weather .' 311 Educational ;••••. ^^Z Agricultural instruction in the University 317 Agricultural instructjon in the State 318 Farmer's Short Course 319 ILLUSTRATIONS Fig. 1 . Alfalfa in seed near Yuma Frontispiece Fig. 2. Johnson grass on Experiment Station Farm near Mesa 243 Fig. 3. Sudan grass at Yuma 244 Fig. 4. Dwelling and farm buildings at Prescott Dry-farm 263 Fig. 5. Tcpary beans in Sulphur Spring Valley 268 Twenty Seventh Annual Report ADMINISTRATION By reason not only of abundant crops, but of high prices for agri- cultural products, and, also, of markets that for the most part readily absorbed the output of grazing ranges and cultivated farms, the agricul- tural year in Arizona has been one of unprecedented prosperity. This has been true not only of grazing ranges from which have been mar- keted a surplus of mutton, wool, and beef, and of irrigated farms whose varied products are gradually establishing themselves in sufficient quantity and of such quality as to win recognition in distant mar- kets, but also to an increasing extent is it true that the hitherto little known dry-farming regions of the State are gradually becoming se- curely established in a peculiar but stable agriculture of their own. To some extent this general condition of prosperity is doubtless artificial, being due to high prices for many articles directly or indi- rectly influenced in price by the European war. It is safe to say, how- ever, that the impetus thus given will never be wholly lost since in- creased agricultural areas, better agricultural organization and im- proved marketing facilities will maintain a higher level of agricultural prosperity than would otherwise have been possible. i" Among the products that have attracted most attention during the year have been Egyptian cotton which, particularly in Salt River Valley, has been developed to the rank of a leading staple. By reason of the Egyptian shortage and of the increasing demand for this cotton for the manufacture of thread, automobile tires, and other purposes where great strength is necessary, the price of the 1916 crop in Salt River Valley reached unprecedented figures. Wool, likewise, because of the •destruction of great quantities of wool fabrics in Europe and the cur- tailment of importations, has advanced to a very high price, with conse- quently beneficial results to sheep grazing interests on the range. In ir- rigated sections alfalfa seed, although prices have been moderate, has 240 Twenty-seventh Annual Report been very profitable on account of pbenomenal yields, over 1,000 pounds per acre of alfalfa seed having been recorded in the Yuma sec- tion. Feeding stuffs in general have been high-priced and readily salable, partly because of the military market along the Mexican line and partly because of considerable areas which have been turned from alfalfa into cotton, wheat and other crops. Grains in general, including wheat, barley, milo maize and other sorghum grains, have produced well and have brought high prices. The cost of feeds, in fact, has reacted somewhat unfavorably upon livestock interests dependent upon them and in some cases has led to shipments of unfinished stock to localities affording cheaper materials with which to finish for market. The great diversity of crops not only possible in the region, but which year by year are coming into commercial development, continues to be an astonishing feature of the irrigated sub-tropical Southwest. No less than forty-nine such crops are known in the Salt River Valley, which is typical agriculturally of the general region. This diversity is practi- cally equal to that of the State of California or of the thousand mile span of agricultural country lying between the Gulf of Mexico and the Canadian line. The stability and the intensive possibilities of this region, agriculturally considered, are beyond question, a fact which is reflected in the improved conditions which are more and more evident from year to year — better knowledge of agriculture, better farming practice, better co-operation for the solution of agricultural problems, and better agricultural service on the part of public agencies. Respond- ing to this generally improved condition, land values have within the year appreciated considerably and a noteworthy influx of farmers from other sections of the United States is to be observed. THE EXPERIMENTAL FIELD Extraordinary diversity characterizes the agriculture of the South- west not only as to soil conditions, which include extreme alkalinity, diverse physical characteristics and varying chemical composition; and as to rainfall, which ranges from almost nothing to almost humid in amount ; but also as to temperature conditions, ranging from sharply frosty in winter to extremely high in summer. Geographically, agricul- tural locations are distributed from a point about 90 feet above sea level at the southwest corner of the State, where crops can be planted or harvested every month in the year, to an agricultural altitude of 7000 feet, where only quick-growing summer crops can be produced. Deal- ing therefore with a variety of subjects as great as may be found in Arizona Agricultural Experiment Station 241 the neighboring- State of CaHfornia or as may be found between the Gulf of Mexico and the Canadian hne, demands made upon the Agri- cuUural Staff are very diverse in character. While, however, the State of California has an Agricultural Staff of 130 men to handle their situation, and while the agricultural zone between Canada and the Gulf i? served by a whole group of agricultural colleges and experiment sta- tions, Arizona, which, on account of its unique agricultural conditions receives less than the usual amount of help from outside organizations, must handle its problems with a staff at present numbering 21 people. Inevitably, in order to work effectively, this Staff has concentrated its efforts from year to year upon a comparatively small number of prob- lems, laying aside completed work from time to time and taking up new projects as time and funds have allowed. In this way, the efforts of the Staff" having been shaped largely by demands made upon it by the agricultural public, the research work of the Station has for the most part fallen under three general heads re- lating to (1) the development and eff'ective utilization of agricultural water; (2) intensive cultivation of irrigated lands; and (3) the utiliza- tion, by dry-farming methods and by grazing, of lands for which there is but limited water supply. With reference to internal organization this work has been carried on by departments of research classified according to technique as follows : agronomy, animal husbandry, botany, chemistry, entomology, horticulture, plant breeding, and irrigation. Following is a classified list of subjects, exclusive of the 27 Annual Reports, thus far published upon by these departments, comprising 77 Bulletins and 123 Timely Hints for Farmers, besides a considerable list of papers published in scientific journals and a constant output of news- paper articles, addresses and other instruments of information : Soils, water, alkali and farm management 35 Climate 6 Crops 90 Weeds, insect pests, and plant diseases 23 Irrigation 17 Animal industry and the range 29 This fund of agricultural information constitutes a body of knowl- edge indispensable at a time when increasing immigration and a quick- ening in agricultural development has made more urgent the public demand for such information. This body of agricultural knowledge also serves as a basis for teaching, more particularly in the sub-tropical and semi-arid region which constitutes the field of work. Indeed, until such knowledge had been achieved it would hardly have been possible to establish a satisfac- 242 TWENTY-SDVENTH ANNUAL REPORT tory scheme of agricultural instruction in and for the State. Such a scheme, however, is now under development in the high schools of the State under the provisions of the Vocational Pursuits Law, in the two normal schools, and in the State University. Properly systematized and correlated, these agencies will assist in bringing into common under- standing the body of scientific anl economic information thus far achieved. GENERAL PROGRESS FOR THE YEAR Considerable time on the part of the Agricultural Staff has been devoted to readjustments relating to the occupation of the new Agri- culture building and to changes required in connection with the general University administration. Furnishings for the laboratories and offices have been devised and installed, equipment purchased, and at the same time the usual amount of routine work and correspondence has been carried on by the Staff. THE SALT RIVER VALLEY FARM An item of considerable magnitude and importance has been the reclamation of the new Station Farm between Mesa and Tempe, Ari- zona. At the time of its acquisition this property was in a condition of considerable disrepair and a large portion of it was densely seeded to Johnson grass, making a preliminary campaign of reclamation neces- sary before a scheme of experimental and demonstration work could be installed. Worthless trees and old orchards were grubbed up, use- less ditches were plowed in, new fences were built, the two old residence buildings were repaired for temporary use, and a general plan of improvements for the place was drawn up and accurately surveyed. The City of Mesa was permitted in the course of the year to lay an outlet sewer across the southern edge of the place, four inlets being provided, with which it is the privilege of the farm to make connection at a future time if desired. At present, therefore, this property, which lies one mile from the city limits of Mesa, has telephone, gas, electric light and power, and sewerage facilities, and in addition is readily ac- cessible from the State Highway by stage lines connecting with all parts of Salt River Valley. The plan of improvements also calls for a siding and a small station of the Arizona Eastern Railroad, affording additional means by which the public can reach the farm. Four methods of reclaiming the land from Johnson grass are be- ing tried : ( 1 ) Continuous dry fallow, both summer and winter, until the Johnson grass is under control: (2) dry fallow in summer with Arizona Agricultural Expe;riment Station 2-13 winter crops of barley, wheat and oats; (3) winter fallow with in- tensively cultivated summer crops of Egyptian cotton and Indian corn ; and (4) pasturing of ditches and waste ground by means of sheep. In this latter connection the Arizona Eastern right-of-way adjoining the farm, hitherto a jungle of Johnson grass, has been leased and already brought under control by means of sheep. Fig- 2 The Experiment Station Farm near Mesa, September 3, 1915, showing dense growth of Johnson grass which has since been brought under control. According to experience gained, the first method entails expense with no income, and the grass is as yet far from exterminated. In (2) the expense of maintaining summer fallow is offset and a clear profit may be gained from the crop of winter grain. In (3) Egyptian cotton has this year yielded a handsome profit in spite of the large amount of hoeing that was done in order to keep the crop entirely free from grass, while the corn just about offset the expense of intensive summer culti- vation. In the case of sheep, not only were ditches kept clean with a minimum of expense, but the railroad right-of-way, composed of ir- regular ground which could not have been handled in any other way, was brought under control not only at a large saving, but with a small profit from the operation. At present it appears that a combination of sheep and intensive cultivation will take care of the Johnson grass problem in southern Arizona much more profitably than by the old expensive method of continuous dry fallow. Experimental acres of alfalfa, lettuce, and various winter growing 244 Twknty-se;venth Annual Report green manuring crops have been planted on the northeastern forty acres of the farm for the season of 1917, while the scheme of reclamation outlined above is being continued upon the other weedier portions of the place. THE YUMA DATE ORCHARD At the Yuma Date Orchard horticultural plantings have been con- tinued between the rows of date palms, plant breeding work has been continued on a portion of the place, and the new block for horticultural planting has been leveled and enriched by means of two crops of Fig. 3. Sudan giass m Vumu, August 28, 1916. One week's difft-Tence in age ol' two plots. tepary beans ploughed under in preparation for fruit trees the follow- ing season. This garden continues to be one of our best kept agricul- tural properties, and the new Warrenite roads which now pass the property on the south and west sides, and which carry practically all of the travel between Yuma and the lower valley, contribute to its value as an object lesson and as a source of information to the rural popula- tion. The Yuma property has been improved by means of new fencing and additions to the residence building during the year. THE TEMPE DATE ORCHARD Improvements to the residence at the Tempe Date Orchard have been made ; and the old structures, used as packing sheds, have been Arizona Agricultural Experiment Station 245 replaced by a new structure which contains rooms for ripening, pack- ing and displaying the product of the orchard. The crop of 1916 was very much inferior to that of 1915, not only because the trees set less than half the number of clusters of fruit, but also because a heavy rain early in September caused a large portion of the crop from many varieties to sour. The total sales from the crop of 1915 amounted to ^4734. 10, while those from the crop of 1916 amounted to $1563.79. These two years' experience, one of them the most prosperous and the other the most unsatisfactory in the history of the orchard, afi'ord us excellent means of judging the vicissitudes to which the crop in this dimate is liable and enables us to strike a fair average of performance for a number of the more promising varieties of dates at the orchard. A feature of the year's work with dates has been the installation on the Mesa Farm of a propagating house for date suckers according to the plan developed by the U. S. Department of Agriculture in the Coachella Valley, California. This house, the sides of which are con- structed of boards coated with paper roofing and the top of which con- sists of 10 oz. canvas, affords in summer a hot and humid atmosphere and a diffuse light evidently very favorable to the rooting and growth of offshoots, while in winter the newly rooted plants, which are very susceptible to cold, are protected from frost. This method, which at least affords success in the rooting of suckers, solves what has thus far been a most serious problem in connection with the date industry, and puts horticulturists in position to propagate much more rapidly desirable varieties of palms. THE DRY-FARMS The dry-farms at Prescott and Cochise have had a fairly successful year, particularly the one at Cochise in the Sulphur Spring Valley, where the summer rains were somewhat more favorable than usual and afforded excellent crops of Tepary beans, milo maize, feterita, and Sudan grass. A silo was constructed during the year and filled with silage products on the place. The year's work, indeed, has seemed to demonstrate a successful scheme of agriculture for the Sulph ir Spring and similar valleys in the Southwest. The salient features of this plan are, the most effective use of rain- fall, quick growing drouth resistant crops, silos, livestock and the skillful supplemental use of grazing range, dry-farming and irrigating resources available within the region. The supplemental use of the various resources referred to is of particular importance to the dry- farmer in this region, for he must combine grazing, rainfall and 246 Twenty-seventh Annual Report t> ^round-water resources in a manner to reap the benefits and avoid the disasters incident to the use of any one of these alone. The stockman, relying upon the grazing range alone, is subject to disaster by drought. The dry-farmer, relying upon rainfall alone, will Ukewise often fail through want of an adequate water supply. The pump irrigator alone will fail because he cannot afford the cost of his pumped water supply ; but upon the combined resources of the grazing range, the dry-farmer and the irrigator, a scheme of agricuUure can be built up that combines all of the advantages mentioned and avoids the disaster almost certainly resulting from dependence upon any one of them alone. The grazing range, for instance, with its rich burden of green feed during the rainy season, supplements the dry- farmer's silo; and the water sup- plied by the pump irrigator at times when water must be had to start or save a crop, supplements the rainfall upon which the dry-farmer must mainly rely. This cooperation between cheap range feed, dry- farm forage supply available as silage, and pumped or stored water supply used in time of need, together with a scheme of livestock adapted to the best use of forage supplies, points the way towards the utilization of hundreds of thousands of acres of lands in a region of which it was formerly said that it could only be farmed by means of a copious irrigating water supply. THE northern ARIZONA DRY-EARM Operations at the dry-farm near Snowflake, Arizona, were dis- continued because of the great distance from supervision and the diffi- culty, therefore, in securing satisfactory returns for the money ex- pended upon the work. Continuation of dry-farming operations at a third location in the State has not as yet bee-n decided although it is recognized that an agricultural region of higher altitude and conse- quently peculiar conditions exists between 5000 and 7000 feet elevation. This region is distinguished by its short summer growing season and is limited to such quick growing crops as early potatoes, oats, certain varieties of corn, vegetables, and some of the deciduous fruits. REQUIREMENTS FOR FUTURE PROGRESS The physical properties of the several departments of the College of Agriculture are at this time fairly complete and satisfactory, consisting not only of office and laboratory facilities in the Agriculture Building on the University Campus, together with adjacent gardens and the University Farm, but also consisting of outlying cultivated tracts — the Arizona Agricultural Expe;riment Station 247 Station Farm near Mesa, the cooperative date orchard near Tempe, the mtensively cultivated garden at Yuma and the dry-farms near Prescott and Cochise, respectively. This organization of facilities affords not only the advantage of affiliation with the general University organiza- tion, but also affords wide contact with the diverse agriculture of the State. As pointed out in the preceding paragraphs, the personnel of the Station is small in proportion to the diversity of the agriculture which it serves, and as opportvinity offers personnel should now be built up in order to make the best use of the physical facilities available. At this time particularly executive assistance is needed in order that sys- tematic and thorough administration of the affairs of the College of Agriculture and Experiment Station may be maintained. This is par- ticularly true in connection with the outlying farms situated at a dis- tance from the University Campus, which are increasing in the amount and complexity of operations carried on. It is necessary in this con- nection to maintain suitable records of work done, to install proper systems of cost accounting in connection with crop demonstrations, to keep track of public needs and wishes in connection with experiments undertaken, and in other ways provide for the greatest pos'^ible useful- ness and efficiency of this work. Within the campus itself there is the same need for more time in which to study the requirements, the possi- bilities of usefulness and the actual efficiency of departments of work. These objects can only be obtained by means of assistance sought for, a fact to which the attention of our authorities has been called both in written reports and in verbal communications, for several years past. In view of the opportunity for economic demonstrations of farm crops which exists upon all of the farms at this time, it is recommended that provision be made for the assistance mentioned along farm manage- ment lines, and appointments to this effect are at this time urged. Properly organized, such assistance will also relieve the scientific staff of a good deal of executive work with which it is at this time burdened and enable its members to devote themselves more eft'ectively to research, teaching, and extension activities expected (.f them by the agricultural public. PERSONNEL The personnel of the Agricultural Staff has remained substantially the same during the year, but with several shifts between different de- partments of service. 248 Twenty-seventh Annual Report For a period of about ten months the Director was on leave of ab- sence in Riverside, Cahfornia, completing a long standing research relating to the mining waste problem in certain irrigated districts in Arizona, and, incidentally, studying the agriculture of a district re- sembling southern Arizona but older in experience and more highly developed in its methods. Professor G. F. Freeman assumed the duties of Acting Dean and Director of the College of Agriculture and Agri- cultural Experiment Station for the time mentioned, and it is under his direct supervision, with the collaboration of the Director, that the work of the year has been accomplished. A. M. McOmie, for six years Assistant Agriculturist in the Station, went into commercial work January 1, 1916, and was succeeded by Professor John F. Nichol- son, of St. Louis, as Agronomist, and Mr. H. C. Heard, of Moscow, Idaho, as Assistant Agronomist. Mr. Leonhardt Swingle, for one year Assistant in Plant Breeding, went into commercial work January 1, 1916, and was succeeded by Mr. Walker E. Bryan, of Alabama. Mr. C. R. Fillerup, foreman of the dry-farm at Cochise, was promoted to be County Agent in the Extension Service in Navajo County. Mr. L. L. Bates, foreman of the Prescott dry-farm, went into commercial work near Prescott, and was succeeded by Mr. Hyrum Dana. Mr. D. C. Aepli, of the old Station farm near Phoenix, was transferred to the Yuma garden ; and Mr. C. J. Wood, formerly of the Yuma garden, was transferred to the foremanship of the new Station farm near Mesa. Miss Helen M. A. Miller, for several years Librarian and Secretary, was succeeded by Miss Frances M. Wells as Secretary. Mr. J. A. Armstrong, Farm Advisor for Maricopa County, resigned June 1, 1916, to go into commercial work, and his place has not as yet been filled. Mr. Stanley F. Morse, for three years Superintendent of Extension also resigned August 15, 1916, to go into commercial work, and he was succeeded by Professor Estes P. Taylor as Director of the Extension Service. PUBLICATIONS Publications for the year, including Annual Reports, Bulletins, Timely Hints for Farmers, and scientific papers are as follows : Bulletin 11, June 1, 1916. Practical Fig Culture in Arizona. — By W. H. Lawrence. Twenty-sixth Annual Report, December 31, 1916. — By the Station Staff. Timely Hints for Farmers : No. 111. September 1, 1915. Irises for Southwestern Gardens. —By J. J. Thornber. Arizona Agricultural Experiment Station 249 Ko. 112. October 1, 1915. Garbanzo Culture in Arizona. — Bv R. H. Forbes and Stanley F. Morse. No. 113. December 1, 1915. Orchard Heating. —By Donald F. Jones. No. 114. March 1, 1916. Producing Guaranteed Eggs. —By R. H. Williams. No. lis. February 1, 1916. Infectious Abortion in Cows. ■ —By R. H. Williams. No. 116. May 1, 1916. Sugar Cane in Arizona —By A. M. McOmie No. 117. May 1, 1916. Vines for Shade and Ornamental Planting. — By J. J. Thornber. Papers published in scientific and technical journals: The Utilization of Groundwater by Pumping for Irrigation Trans. International Engineering Cong., 1915. Waterways and Irrigation. Volume , pp. 414-444. —By G. E. P. Smith Duty of Water in Irrisation. Ibid, pp. 494-496. —By G. E. P. Smith. Duty of Water and Eyaporation-ratc. Twenty-second International Irrigation Cong., 1915. —By G. E. P. Smith. Composition of Salton Sea Water. June 10, 1916. Carnegie Institution of Washington, Year Book No. 15, 1916, p. SS. — By A. E. Vinson. Quality vs. Number in Range Cattle. Arizona Cattle Growers' Assn., Ninth Annual Report. —By R .H. Williams Registered z'S. Scrub Sires on the Range. The American Hereford Journal, June 1, 1916. — By R. H. Williams. The Practical Application of the Ferris Stock-raising Homestead Bill to Our Western Grazing Ranges. Proc. Nineteenth Ann. Conyention Amer. Live Stock Assn., 1916. p. 116. — By J. J. Thornber. FINANCIAL Financial resources for the year ending- June 30, 1916, were as follows : Hatch Fund, from tlie U. S. Treasury $15,030.00 Adams Fund, from the U. S. Treasury 15,000.00 Sales fund balances from 1914-15 $ 2,022.12 Sales funds 1915-16 as follows: Salt Riyer Vallev Farm, Mesa $ 613.35 Yuma Date Orchard 824.47 Tempe Date Orchard 4.734.10 Prescott Dry Farm 200.(X) Sulphur Spring Valley Dry Farm 21.77 Hatch Sales Fund ' 2,368.05 8.761.74 $10,783.86 Less remittances to ■State treasury 1.941.61 Balances on 'hand S36.M 2.477.92 8,305.94 State appropriations: Balances from 1914-15. 507.73 250 TWKNTV-SEVENTH ANNUAL REPORT Appropriations for 1915-16: Date Palm Orchards $ 3,500.00 Sulphur Spring Valley Drv Farm 4,160.00 Dry Farming Sec. 26 3,000.00 Dry Farming Section 27 A 4,600.00 Northern Arizona Dry Farm 3,200.00 Yuma Horticultural Station 700.00 Plant Introduction and Breeding 3,000.00 Underflow Investigation 2,750.00 Salt River Valley Farm 3,000.00 Printing and Binding ( Agri. ) 1 ,500.00 Maintenance 9,241 .06 $38,651.06 Less balances to 1916-17 5,105.88 33,545.18 $72,358.85 A statement of expenditures by schedules and by funds is also submitted herewith. R. H. Forbes, Director. e;xpi:nditurES by funds and schedules for the year ending JUNE 30, 1916 Abstract State Appro- priations Salaries Labor Publications Postage and stationery Freight and express.. Heat, light, water and power Chemicals and labora- tory supplies Seeds, plants and sun- dry supplies Fertilizers Feeding stufifs Li1)rary Tools machinery and appliances Furniture and fixtures Scientific apparatus and specimens Livestock Traveling expenses. . . Contingent expenses.. Building and land. . . . Balance $ 9,841.26 6.833.37 1,637.99 44.43 2,769.38 158.56 454.33 662.37 4,297.33 584.71 1,897.51 32.50 4.839.17 Sales Funds $34,052.91 $■ 2,974.27 'i32.li 108.19 548.50 895.65 7.31 9.45 590.95 133.35 278.56 18.00 679.95 318.93 1,610.72 Hatch Fund Adams Fund $ 7,276.98 5,199.46 4.85 615.21 7.12 126.91 111.72 244.53 91.75 67.90 13.50 311.92 31.83 26.50 2.00 620.45 20.00 977 3? .05 $10,647.39 1,281. OS (Omit) 57.53 111.00 30.75 254.18 146.07 185.38 185.40 1.35 141.12 5.00 995.36 ""599.43 ""354.60 4.39 Toial $8,305.94 ! $15,000.00 $15,000,00 $27,765.63 16,288.15 1,642.84 804.85 270.74 706.16 365.90 4.055.63 443.00 717.08 14.85 1,706.36 4,467.51 1.300.42 604.71 3,797.34 371.43 7,031.81 4.44 $72,358.85 AGRONOMY Experimental work in agronomy for the year has inckuied opera- tions upon the old Experiment Station farm near Phoenix previous to removal from that place June 30, 1916; the initiation of work upon the new Experiment Station farm between Tempe and Mesa ; dry- farming operations on the Prescott Dry Farm near Prescott, and on the Sulphur Spring Valley Dry Farm near Cochise, Arizona. This work has therefore included experiments and demonstrations on a wide variety of soils under irrigation and by dry-farming, and with a con- siderable range of atmospheric conditions. A good deal of informa- tion has been obtained relating to standard crops — wheat, barley, oats, alfalfa, beans, and sorghum grains, as well as with some new crops in the region. The work finishing operations at the old farm near Phoe- nix is reported in considerable detail. The plan of reclamation at the new farm near ]\Iesa is outlined and a table of the first season's results is submitted. A summary for the work done at the Prescott and Sul- phur Spring Valley Dry Farms for the year is also given. PHOENIX FARM The experimental crop work on the Phoenix Farm this year was limited to small grains, flax, and alfalfa. The work was limited on ac- count of the intention to discontinue experimental operations on this farm at the end of the fiscal year 1916. The character of the soil is designated as Maricopa sandy loam. Little attention has been paid to the maintenance of fertility in previous years, hence the quantities of the crops are below the average. Since, however, most of the experiments were variety tests, the relationship tetween yields of grains tried can be quite accurately observed. CROPS GROWN Wheat : The work for the year demonstrated the superiority of fall over spring planting. All of the 21 varieties tested this year were planted in the fall. All seed used in the tests was treated with formalin for smut. Xo introduction of new varieties was made, hence all seed of this year's plantings were grown on the farm last year. The season was such that very little rust appeared. The Early Baart and the Little Club were the only varieties showing this disease in in- jurious amounts. The following table gives the varieties in the order of their production, and also shows dates of planting, harvesting, irri- gating and rate of seeding per acre. 252 Twe;nty-Se;venth Annual Report TABLE I. VARIETY OF TESTS Variety Date planted Rate seeding per acre Date har- vested Yield per acte Dates irrigated pounds pounds Early Baart 11-15-15 75-80 5-18-16 2460 11-22-15 2-11-16 White Aus- tralian. . . . 11-15-15 75-80 5-18-16 2420 11-22-15—2-11-16 Little Club 11-15-15 75-80 5-12-16 2380 11-22-15 12-11-15 4- 5-16 Marquis . . . 12-20-15 75 6- 6 V' 2128 11-18-15- 2-11-16—3-13-16 Koffoid ... 11-15-15 75-80 5-29-16 2060 11-22-15— 2-11-16 Wild Wheat 11-29-15 75-80 5-23-16 11-18-15 12-11-15 4- 5-16 Marquis . . . 11-15-15 75-80 5-22-16 1900 11.22-15—12-11-15—2-11-16 Sonora . . . 11-29-15 75-80 5-18-16 2060 11-18-15 12-11-15 3-13-16 Kubanka. . . 11-29-15 75-80 5-23-16 1820 11-18-15—12-11-15—4- 5-16 Red Chaff 11-15-15 75-80 5-31-16 1900 11-22-15 12-11-15 3-13-16 Red Fife... 11-26-15 75-80 5-29-16 1800 11-18-15 12-11-15 3-13-16 White Aus- tralian. . . . 11-29-15 75-80 5-29-16 1700 11-18-15—12-11-15—2-11-16 Arinaviar . . 11-29-15 75-80 5-31-16 1700 11-18-15—12-11-16 Macaroni . . 11-15-15 75-80 5-22-16 1680 11-22-15— 2-11-16 Crimean . . . C. I. 1435.. 11-29-15 75-80 5-31-16 1660 11-18-15 12-11-15 3-13-16 Blue Stem 11-15-15 75-80 5-22-16 1660 11-22-15 2-11-16 Defiance . . 11-15-15 75-80 5-23-16 1640 11-22-15— 2-11-16 Turkey Red 11-15-15 75-80 5-29-16 1640 11-22-15— 2-11-16—3-13-16 Buls^arian . . 11-29-15 75-80 5-31-16 1260 11-18-15 12-11-15 2-11-16 Red Russian 11-15-15 75-80 6- 6-16 1200 11-22-15 2-11-1^-4- 5-16 Kharkov. . . C. I. 1442.. 11-29-15 75-80 5-31-16 1100 11.18-15-12-11-15—2-11-16 Crimean — C. I. 1437.. 11-29-15 75-80 5-31-16 1040 11.18-15—12-11-15—2-11-16 Buffum No. 17 11-26-15 75-80 6- 6-16 1040 11-18-15 12-11-15 It will be noted from Table I tbat Early Baart gave the hiohest yield of grain. White Australian, Little Club and ]\Iarquis were not far behind. Early Baart is quite generally grown throughout the Salt River Valley, and meets the demands of the millers generally. With this taken into consideration its yielding capacity would recommend it highly as a standard variety for this section. Marquis is a consider- ably better milling wheat than Early Baart, but so long as the local market will not pay higher prices for it than it does for the softer wheats, and the local production is not equal to the local demand, Early Baart can be profitably grown as the standard variety. The hard winter and durum wheats did not show up as well as the varieties mentioned above, and it is doubtful if it would be advisable to encourage their production at this time. Two plats of Marcjuis, planted November 15 and December 20, respectively, gave a difiference of 228 pounds per acre in favor of the later planting. This can be explained by the better seed bed conditions at the later planting date. The November planting was irrigated by Arizona Agricultural Experiment Station 253 an application of water seven days after sowing, which is a bad prac- tice. The December planting was made in a seed bed which had re- ceived water November 18 and December 11, respectively. The latter irrigation placed the seed bed in excellent condition for planting nine days later. The two plats of White Australian show a difference of 720 pounds per acre in favor of the November 15 planting as compared with the November 29 planting. There were two factors that may have had a bearing on these results. The November 29 planting was made on a more gravelly plat than the other, and the seed for the November 15 planting was home grown, while that for the other came from Yuma. Seed should be locally grown, when of good quality, on account of the influence of acclimatization. In the case of the heavier yield the crop was irrigated subsequent to seeding, as it was with several of the other plats, but in spite of this improper practice the yield was greater than the White Australian grain on the poorer soil. Barley: Nine varieties of barley were included in the variety test plats this year. All of these were sown in the fall. No spring planting was made on account of previous year's trials showing the fall planting superior to the same varieties planted in the spring. Table II gives the varieties in the order of yields per acre, and also indicates the dates of planting, harvesting, irrigating, and rate of seed- mg per acre. All of the seed was treated for smut with formalin, which resulted in there being no smutted grain in any of the plats. All of the seed was grown on the farm last year. TABLE II. VARIETY TESTS OE BARLEY Rate Date Dianted seeded Der Date har- Yield per Dates irrigated Variety ^^ A ^Af a & ^ V^ V* acre vested acre pounds pounds Beldi ... 11-26-15 75-80 5- 6-16 2580 11-18-15 12-11-15 3-13-16 Tennessee Winter. . 11-29-15 75-80 5-12-16 2200 11-18-15 12-11-15 Chevalier 11-29-15 75-80 5-12-16 2160 11-18-15 12-11-15—4 -5-16 California 6-Row. . 12-27-15 90 5-13-16 2000 12-11-15 3-13-16-4- 5-16 Mariout 11-26-15 75-80 5- 8-16 1840 11-18-15 12-11-15—4- 5-16 California 6-Row. . 12-26-15 75-80 5- 8-16 1680 11-18-15 12-11-15 2-11-16 Black Hull less 11-26-15 75-80 5- 8-16 1440 11-18-15 12-11-15 3-13-16 Day.... Brewing 11-26-15 75-80 5-11-16 1440 11-18-15—12-11-15 Utah Win- ter 11-29-15 75-80 5-31-16 1220 11-18-15 12-11-15 3-13-16 W h i t e Hulless 11-26-15 75-80 5- 8-16 1060 11-18-15—12-11-15—3-13-16 254 Twenty-seventh Annual Report Beldi, a common bearded variety, gave the best yield. Tennessee Winter barley, another bearded type, was second, and Chevalier, a 2- rowed bearded barley, was third. Last year the Utah Winter barley was the heaviest yielder out of ten varieties planted in the spring, but proved a very poor producer when planted this year in the fall. The California 6-row barley was planted on two dates, November 26 and December 27, respectively. The December planting gave a higher yield by 320 pounds per acre. The November 26 plat was badly in- fested with burr clover which may have accounted for some of the dif- ference in yield. Since much of the barley grown in Salt River Valley is used for hay, it is highly desirable to secure a beardless variety. White Hulless has a hooded spike, and it was hoped that it might prove sufficiently productive to encourage its general introduction. Its yield of 1060 pounds per acre placed it lowest in the list. Further work is desired along this line either with this variety or some other possessing the advantage of beardless spikes. Oats: Nine varieties of oats were sown in the fall. The previous year's tests gave much better yields for the fall planted plats as com- pared to those planted in the spring. All seed was home grown, except one plat of Red Algerian which came from Yuma and gave 580 pounds per acre better results than the home grown Red Algerian seed. All of the seed was treated for smut with formalin, which resulted in practi- cally no loss from this disease. Table III gives the varieties tested arranged according to yields per acre. The table also shows dates of planting, harvesting, irrigation and rate of seeding per acre. TABLE in. VARIETY TEST OF OATS r>ate Rate seeding Date Yield Dates irri gated Variety planted per harvested per acre acre 1915 1916 pounds pounds San Saba 11-15-15 75-80 5-23-16 2900 11-22—12-11 3-13 Texas Red.. 11-26-15 75-80 5-17-16 2680 n it ... 4-5 Australian Rust Proof 11-15-15 75-80 5-17-16 2400 II II Alberta Red 11-15-15 75-80 5-23-16 2060 tl II Red Algerian 11-29-15 75-80 5-31-16 2020 II II Calif. Red.. 11-15-15 75-80 5-11-16 1680 Boswell Black Winter 11-29-15 75-80 5-31-16 1100 " 12-11 Red Algerian 11-26-15 75-80 5-17-16 1440 II ii Black Eagar 11-15-15 75-80 5-23-16 1000 Texas Red.. 12-29-15 75 5-24-16 800 2-11 " The Texas Red oats gave the highest yield of grain last year but was surpassed by San Saba this year. The Australian Rust Proof Arizona Agricultural Exterimlnt Station 255 proved a very good producer this year. Texas Red Oats were planted November 26 and December 29, respectively. The latter planting was practically a failure with only 800 pounds production per acre. With a production of 2900 pounds of oats per acre there is no question as to the place of this grain in Salt River Valley or other irrigated sections of the State. For feeding upon the farm to work horses during the hot season they are superior to barley, and should find a place in limited acreage on every farm. Rye, cuimcr and spelt: One plat of rye was planted December 9, 1915, at the rate of 50 pounds per acre. This was irrigated four times, including the application of water prior to sowing for the pur- pose of putting the seed bed into shape. The crop was harvested May 23, 1916, giving a yield of 1200 pounds per acre. There is little profit in growing rye with this low production. This, in view of the limited market for this grain, makes it a questionable crop for the irrigated sections of the State. Only one plat of Black Winter emmer was tried this year. This was sown November 26, 1915, at the rate of 75 to 80 pounds per acre. The stand came 90 per cent about two weeks after planting. The plat was irrigated eight days previous to sowing, and again on December 11. Harvesting was done May 31, 1916, showing a yield of 1540 pounds per acre. Emmer produced some 3600 pounds per acre last year on the farm, but even with such yields it is doubtful whether it is a paying crop to grow on the highly improved irrigated lands of the State. It has a place in the crop system of the dry farms of the State, and is proving very valuable there. With good crops of barley, oats, and wheat, the irrigation farmer fills his needs for small grain crops, and will find tiiem much more satisfactory to grow than emmer. Only one plat of spelt was tried this year. This was sown Novem- ber 26 on land irrigated eight days previous. Seeding was done at the rate of 75 to 80 pounds per acre, which gave an excellent stand. The crop was irrigated once after seeding, and harvested June 6, 1916. The yield was 1200 pounds per acre. There is no reason for encouraging the growing of spelt on our irrigated farms. Other and more profit- able crops should be adopted on such highly developed and expensive land. Field peas, reteh and ehick-peas: Two varieties of field peas — Colorado Stock and Canadian — were planted November 29, with re- sults so poor that the crops were not harvested. Spring and Winter vetch planted December 9 failed to germinate. The chick-peas planted 256 Twenty-seventh Annual Report November 15 made a very meagre growth, failed to form any seed, and were plowed up as a failtire. More extensive investigations are planned for next year w-ith these legumes as forage and green manur- ing crops. Our soils are deficient in humus, and it is particularly desir- able that a proper winter legume be found for green manuring pur- poses. The cause of the above failure will be studied, and if possible methods found to grow them successfully in Arizona. • Approximately seventeen acres of the farm were devoted to alfalfa. This was cut twice from January 1 to July 1, yielding the following amount of dry hay : First cutting- April 5 to 10. Yield 33495 lb. Second cutting May 22 to 25. Yield 48325 lb. Average for 2 cuttings, 2.4 tons per acre. The alfalfa was cultivated with a spring-tooth harrow January 10. It was irrigated on the following dates : February 22, March 20, April 21, May 4, and May 17. As stated before, all experimental work on the Phoenix Farm ter- minated July 1, 1916. On that date the alfalfa was about ready to cut for the third time, but was left for the lessee, who took immediate possession. flax: The flax testing jilats were continued again this year, using the same varieties tested last year and a considerable number of others furnished by the U. S. D. A. This work is done in cooperation with the Department of Agriculture under the immediate supervision of Charles H. Clark, Assistant Agronomist in charge of Flax Investiga- tions. Six varieties. North Dakota Resistant, Select Russian, Smyrna, Punjab, Boulga, and Soddo Brown, were growai in one-fourth acre plats. In these seeding was made in 6-inch drill rows. Table IV gives the results of these plantings together with in- formation as to date of seeding, harvesting and irrigation. TABLE IV. FLAX IN ONE-QUARTER ACRE PLATS Variety Govt C. L No. Date planted Date harvest- ed Yield per / acre Dates of irrigation bushels N. D. Resistant Select Russian Smyrna Punjab Boulga Soddo Brown. . 13 3 30 20 37 38 12-24 12-24 12-24 12-24 12-24 12-24 5-11 5-11 5-25 5-25 5-25 5-25 9.6 8.6 10.4 7.1 10.0 8.6 12-11 2-11 2-29 3-13 3-21 4- 1 4-20 5- 3 12-11 2-11 2-29 3-13 3-21 4- 1 4-20 5- 3 12-11 2-11 2-29 3-13 3-21 4- 1 4-20 5- 3 12-11 2-11 2-29 3-13 3-21 4- 1 4-20 5- 3 12-11 2-11 2-29 3-13 3-21 4-. 1 4-20 5- 3 12-11 2-11 2-29 3-13 3-21 4- 1 4-20 S- 3 Arizona Agricultural Experiment Station 257 Some thirty varieties were grown in nursery rows and cultivated eight times. Some of the varieties were planted on two different dates, November 8 and December 22, respectivly. Table V shows the results of these test rows, as well as dates of planting and harvesting. TABLE V. FLAX IN NURSERV ROWS Gov't Date Yield C. I. Date harvest- per Variety No. planted* ed acre bushels Tashkent 11 11- 8 6- 9 7.87 Tashkent 11 12-22 6- 9 10.55 Kashgar 50 11- 8 6- 9 7.92 Turkish 7 11- 8 6- 9 5.21 Smyrna 30 11- 8 6- 9 8.55 Smyrna 30 13 34 12-22 11- 8 11- 8 6- 9 5-12 6- 1 5.11 N D Resistant 4.91 Matania 3.24 Hoshangabad 40 11- 8 6- 1 5.31 Hoshangabad 40 12-22 6- 9 11.63 Punjab 20 11- 8 6- 1 %.2,7 Punjab 20 12-22 5-23 13.64 ■ Jalaun 21 21 11- 8 12-22 6- 1 6- 9 7.18 Jalaun 12.26 Benares 28 28 36 36 38 26 11- 8 12-22 11- 8 12-22 11- 8 12-22 6- 1 5-23 6- 1 6- 9 6- 9 6- 1 6.08 Benares 4.86 Soddo White 6.97 Soddo White 12.65 Soddo Brown 5.95 Canadian La Plata 11.94 Nova Rossick 27 12-22 6- 1 14.96 Fargo Common 18 12-22 5-23 11 79 Hay s Seed Flax 16 19 3 4^ • 12-22 12-22 12-22 12-22 12-22 5.23 6- 9 5-23 6- 9 6- 9 6.82 Russian 9.26 Select Russian 6.82 Select Russian 6.48 Select Russian 9.97 Select Riga 2 12-22 5-23 6.08 N. D. Resistant 14 4 12-22 12-22 5-23 5-23 9.26 Kazan 9.00 Primost 12 23 25 12-22 12-22 12-22 6- 9 6- 9 5-23 7.20 Sethbridee Golden 8.83 Williston Golden 10.08 Mundjar 35 12-22 6- 9 7.91 Boulga 27 12-22 6- 9 8.10 Metcha 39 12-22 6- 1 7.70 *An rows planted November 8, 1916, were irrigated 10-26, 2-18, 3-7, 3-21, 4-20 and 5-3. Those planted December 22, 1916, were irrigated 12-11, 2-8, 3-7, 3-16. 4-3, 4-20 and 5-3. This work was intended only as a test of varieties ; however, those varieties planted at two dates, namely, November 8 and December 22, with but two exceptions gave better results with the later planting. All of the flax was badly infested with the false chinch bug at heading time. Frequently all of the bolls on a plat were intensely festooned with these sucking insects. The result of these ravages must have been 258 Twenty-Sevknth Annual Report very instrumental in cutting the yield, and also in lessening the weight of seed per bushel. All of the varieties mentioned in Table V will be continued in test plats and rows another year. Conclusions should not be drawn, there- fore, until a more extensive trial has been made. In general, it can be said that flax growing for seed has indications of being a profitable industry- for our irrigated valleys in Arizona. THE NEW EXPERIMENT STATION FARM The University assumed direct management of the new Experi- ment Station Farm, near Mesa, on July 1, 1915. The place was rather heavily infested with Johnson grass, the fences were old and run down, and in many places the lay of the land for irrigation needed much im- provement. Accordingly the main efiforts on this farm have been di- rected toward improving the irrigation system, fencing, eradicating Johnson grass, and bettering the general appearance of the place. It has not been considered advisable to attempt much experimental work here until the Johnson grass is brought well under control, and the irrigation can be accurately handled. THE JOHNSON GRASS EXPERIMENT The north half of the east 80 acres of the farm was quite free from Johnson grass when the Experiment Station took charge. Aside from this the entire remaining 120 acres were badly infested. Half the Johnson-free portion was planted to wheat and half to alfalfa. Any stray grass in these fields was destroyed by hand digging. In the south half of the east 80 acres, a strip which had been in wheat in the spring of 1915, was set aside to be dry fallowed. It was plowed in August, of that year, and worked down later in the fall with a disc and harrow. A luxuriant crop of volunteer grains came up with the winter rains, and in many places a perfect stand was found. This heavy growth soon seriously depleted the soil moisture, and the Johnson grass growth in the spring of 1916 was very meagre, being confined for the most part to seedlings. This field was again plowed in April. The land was very dry and no appreciable growth of Johnson grass was noted until after the summer rains began. At this time, as before, seedlings were most in evidence. A particularly hard rainstorm in early September soaked the ground quite thoroughly, and gave the seedlings a fresh start. In order to control these the entire field was plowed and disked the third time. The land was in very clean shape, preparatory to seeding to grains in December, 1916. Arizona Agricultural ExpiiRiMi^NT Station 259 The west 80 acres was divided into five fields, three of which con- tained 20 acres each, and two 10 acres each. Four methods of eradi- cation were tried out on these fields: close pasturing with sheep, in- tensive cultivation of intertilled summer crops, dry fallow in summer followed by grain in winter, and continuous dry fallow. The first field contained 20 acres. It was plowed in September and October of 1915 when very dry and hard, leveled and bordered in November, and seeded to barley in December. The dry plowing in 1915 served to check seriously the Johnson grass, and as a result very few plants were showing above the grain while the latter was still standing. The grain was bound about the middle of May, 1916, and the ground was held dry until the middle of June, at which time about 275 sheep were turned in on it. Between the time of removal of the grain and coming of the sheep, a considerable growth of Johnson grass had sprung up uniformly over the field. None of this was allowed to mature seed. After the sheep came, the field was irrigated at frequent intervals in order to force as rapid a growth of Johnson grass as pos- sible. The sheep kept it eaten very close to the ground, and. as a result, the propagating rootstocks of the grass were showing marked lack of vigor by the fall of 1916. In the middle of November, 1916, the land was prepared and seeded to barley for pasture, and it is believed that by the end of another summer the Johnson grass of this field will either be almost totally destroyed or well under control. The remainder of the west 80 acres had been in grain sorghums for a number of years, and the University did no work to eradicate Johnson grass on it in 1915, except to mow some of it and burn over some of the worst of it. Some of the laterals were so badly infested that it was deemed advisable to fill them with straw and burn them out. The first 10 acres of this part was plowed in February preparatory to putting into Egyptian cotton. In order to make this land irrigate perfectlv it was all replowed once and part was replowed a second tune. In this way the grass was constantly disturbed until the mid- dle of April. The cotton was not planted until this late date on account of the work necessary to level the land properly. A cultivator equipped with 8-inch sweeps was put to work in this field in the latter part of April, and was kept going whenever any grass appeared above the surface of the ground. The weeds in the rows were removed by hand hoeing. By the time the cotton had become large enough to shade the ground very little Johnson grass was appearing, and in the latter part of the season the few plants left were almost all from seeds which, presumably, were brought in by the irrigating water. 260 Twenty-seventh Annual Report The next 10-acre field was treated in a similar manner, except that it was planted to Sacaton June corn in the middle of July. This field was first plowed in April. The Johnson grass was kept down by the cultivator until June, when the field was replowed to facilitate leveling. After being put in corn it was again kept under control by the cul- tivator and by hand hoeing. The condition of the Johnson grass at the time of the first frost was much the same as that in the cotton. The remaining 40 acres are divided into two 20-acre fields, both of which have had the same treatment to date. One of these is to be planted in grain in December, 1916, and the other is to be continuously dry fallowed. All of this land was plowed in March and April, and re- plowed in xA.ugust. It was disced in July and September, and after the latter operation was run over twice with a "Cyclone" weeder. The fight against Johnson grass on these two fields, while it has unques- tionably borne good results, has probably been the least effective of that on any of the fields, and there are a number of roostocks remaining V. hich have approximately normal vigor. An exceedingly heavy rain late in the summer and occasional accidental leaking of irrigation water have been largely responsible for reducing the efBciency of the Johnson grass control method on these fields. It appeared advisable on one oc- casion to pasture sheep for a short time on these fields, owing to an increased growth of the grass due to heavy rains. The value of this pasturage from each field was estimated at $4.60 per acre and is the only returns we have received from the fields during the experimnts. WHEAT AND ALFALFA As mentioned above, the north half of the east 80 acres was put mto wheat and alfalfa. This was run under commercial farming con- ditions and was in no sense experimental in its nature, though it had its value for demonstration purposes. This 40-acre tract had been in grain in the spring of 1915. It was plowed dry in August of that year. Twenty acres were prepared for irrigation in November, 1915, and sown to Early Baart wheat on November 25, at the rate of 60 pounds jitr acre. The soil is very fertile, and a heavy stand of very high wheat was the result. Danger of lodging made it inadvisable to give it all the water it needed for complete filling. A very slight damage was caused by rust, and a considerable amount of trouble was experienced from lodging. The yield was slightly more than 1900 pounds of grain per acre, and, in addition, 27 tons of straw were sold. The wheat stubble on 9 acres was plowed up in July and early Arizona Agricultural Experiment Station 261 August, 1916. This land was planted to Sudan grass in the middle of August at the rate of 20 pounds to the acre. This was cut October 28, and an estimated yield of 30 tons of cured hay was obtained. Because of space taken up by a roadway, and by fences, the actual size of the alfalfa yield was slightly less than 14 acres. After having been summer plowed dry, as given above, this land was prepared for irrigation in September and October, and seeded to Hairy Peruvian alfalfa October 24, 1915, at the rate of 17 pounds per acre. The first cutting was made in the middle of March, and was mostly bur clover and volunteer wheat. The second cutting was excellent hay, though it contained a large proportion of volunteer wheat. The remaining four cuttings were all very excellent alfalfa. A total yield of 89 tons (measured) was obtained. No trouble was encountered from Johnson grass in either the wheat or the alfalfa. Table VI gives a brief summary of the costs of operations on the various fields, the sizes, and the returns therefrom. The third to the eighth fields inclusive were within the Johnson grass eradication experi- ment, and our main efforts were directed toward the control of this pest rather than financial profit. TABLE VI. operations, FIELDS, AND RESULTS OBTAINED ON THE SALT RIVER VALLEY FARM AT MESA, 1916 Size Cost Income of per per Remarks Type of farming fields acre acre acres dollars dollars Wheat 20 23.52 31.50 Sudan 9 21.13 33.00 Alfalfa 14 49.5S 56.03 Cost per acre includes pre- paring ground and seeding 1 year dry fallow 40 17.58 None Cost per acre includes 3 plowings, 2 being under very dry conditions Winter grains and On account of over-grazing sheep pasture 20 32.62 27.14 value of .sheep pasture just paid for irrigation expense Intensive cultiva- Johnson grass under con- tion (cotton) 10 72.58 120.00 trol Intensive cultiva- Johnson grass under con- tion (corn) 10 36.70 42.00 trol 1 vear drv fallow and winter grains 20 14.45 Continuous drv fallow 20 12.85 It is the plan to continue the same methods of Johnson grass con- trol on these same fields until the pest seems to be well in hand. 262 TvvENTv-sEvENTH Annual Report The effects of another season's work will undoubtedly shed much light on the situation, and it is inadvisable to draw too many conclu- sions at this date. However, certain points have been definitely noted and certain results have been obtained which are of interest. A discus- sion of these follows : The matter seems to resolve itself into Johnson grass control rather than eradication. Irrigating water brings in enormous quantities of seed each summer, and plants from this source must be continually dealt Vv'ith in the absence of a suitable method for screening out these seeds. It is as easy to control a seedling Johnson grass plant as any other weed, provided the work is done in time. As a usual thing the propagating rootstock starts to develop about the time the head is in the boot, or just before it appears above its protective sheath. Before this time a single cultivation destroys the plant. It follows, then, that after the old rootstocks are destroyed the key to the whole matter is to attack the seedlings before they have had time to develop rootstocks of their own. The cost involved where the grass is kept down by intensive culti- vation is very heavy, but the returns are often great enough to leave a margin of profit. By this method, the farmer can eventually get his place well rid of this pest without being denied the use of his land ; and, by doing a large share of the work himself can accomplish the task without much outlay of actual cash. If this method is to be successful, he must have a cultivator that cuts every bit of plant material between the rows, and he must be able to do the work immediately when the necessity arises. When leaves are formed above the ground, this por- tion of the plant begins to feed the rootstock, and the only way to make any headway is to destroy the growth while the rootstock is feeding the above ground portion. If this is done the vigor of the rootstock is diminished during the best growing season at a surprisingly rapid rate. Dry fallow is not as quick a method as intensive cultivation. A heavy rain may cause enough growth before the field can be entirely re- plowed to restore otherwise depleted rootstocks to normal vigor. Plow- ing in dry ground in hot weather is very expensive and slow work, and the farmer has a difficult situation to face when he has to bear this expense on land that is returning him no income. Pasturing with sheep promises to be a favored method. The suc- cess of this depends on overgrazing. That is, enough sheep must be run on a field to graze every bit of the grass as close to the ground as possible. When the land has an abundance of water and the proper temperature to induce fast growing, the rootstocks can be very rapidly weakened. Sheep have the alditional advantage of keeping ditches Arizona Agricultural Experiment Station 263 clean. When a ditch is grazed thoroug-hly it is left in ideal shape, for the tramping- and grazing of the sheep tend to smooth the sides and bed of the ditch, partially overcome the effects of gophers, and keep down brnsh and willow growth which make horse work difficult. Where a ditch is well grazed with sheep it is very rarely that any other work needs to be done to keep it in condition. It seems highly probable that some headway can be gained by sup- plementing these Johnson grass control methods with fall plowing when practicable. When this is done, a great number of rootstocks will be brought to the surface and either killed or materially weakened by the frosts of winter. PRESCOTT DRY FARM The crops grown on the Prescott Dry Farm this year consisted of corn, beans, peas, grain sorghums. Sudan grass, saccharine sorghums, and small grains. The 50 acres in cultivation were divided into five fields as nearly equal as possible. Each field was then sub-divided into varying sized plats. The plats of any given field were devoted ex- clusively to one class of crops. 1. 1 I W fill lit mmI laiiii iMiildings at the Prescolt I>r\' Farm, Julj' 30. I'.tlti. RAINFALL Rainfall has direct bearing upon the success or failure of the farm- ing operations on this farm. The season this year was very favorable 264 TwKNTY-SEVENTH ANNUAL REPORT * from a rainfall standpoint. Between five and six inches of rain fell during January, February, and March, and five inches fell during the growing season of July, August, and September. The rains were quite uniformly distributed over the growing months, this having much to do with the success of the crops on the Prescott Dry Farm this year. CROPS Corn: The following varieties of corn were planted from May 22 to June 12: Papago Sweet, Hickory King, Bloody Butcher, Reid's Yellow Dent, Silver's White Flint and Blue Squaw. All of the corn was cut for silage except a small patch of Hickory King and Bloody Butcher which was left for seed. Hickory King yielded the largest quantity of green silage per acre, while the White Flint and Blue Squaw were practically failures. Hickory King made 13,320 pounds of green silage per acre ; Papago Sweet, 8,364 ; Bloody Butcher, 6,720 ; Reid's Yellow Dent, 4,500. The small Indian corns have appeared to better advantage during a less favorable season of rainfall and should be included in order to provide against complete loss of all corns when such seasons appear. Beans: Tepary beans and Colorado Pinto beans were the two varieties tested this year. These were planted May 10, but later were nearly destroyed by rabbits. The teparies were completely destroyed and the' Colorado Pintos yielded only 75 pounds of beans per acre. field peas: Six acres of Canada field peas were sown June 15, which was too late to take advantage of any winter moisture that was present earlier in the season. The majority of the peas did not germi- nate until July when the summer rains appeared. The season from this time on until frost was too short for maturing the peas, and the excellent growth of vines which they made during that time was turned under as a green manuring crop with no attempt made to harvest them. Grain sorgliiiins : The grain sorghums tested this year were Early Dwarf White milo. Standard Black Hulled White kafir, and shallu. These were planted June 1 on plats ranging from one-eighth to three-fourths acre in size. The entire crop of all the grain sorghums was harvested for silage except a small portion of the milo which was left for seed. An estimate of the yield of milo seed was 1260 pounds of grain in the head per acre. The yield of green forage was as follows : Shallu 8062 pounds green silage per acre Standard Black Hulled White kafir 5182 " " " " " Early Dwarf White milo 4000 " " " " " Arizona Agkrtltural Experiment Station 265 The grain sorghums are more drought resistant than corn and in a less favorable year would have compared more favorably with that crop. W hile shallu made the heaviest yield of forage it does not make the best silage and its growth should not be encouraged. Saccharine sorgliiiins: Club-top cane, Red-top cane, Early Am- ber cane, and Early Orange cane were tested in plats of more than one acre in size. These sorghums were all sown from May 10 to June 12. Club-top planted May 10 yielded 11,650 pounds of green silage per acre, Club-top planted :\lay 31 yielded 11,456 pounds, Red-top planted June 9 yielded 5775 pounds. Early Orange planted June 9 yielded 8592 pounds, and Early Amber planted June 12 yielded 3686 pounds per acre. The Club-top out-yielded all of the other sorghums, and as a silage crop is very valuable as a supplement to corn. Sudan grass: A little over 8 acres were planted to Sudan grass on May 10. One small plat was planted as late as June 5. This late planted plat was practically a complete failure due not so much to the date of planting as to the poor soil and the depth to which the seed was sown. All of the Sudan grass was planted in rows 40 inches apart with the exception of one-half acre which was set in 20-inch rows. The narrow rows yielded only 1000 pounds of dry hay per acre while the rest of the field, except the late planted plat mentioned above, yielded slightly over 1.5 tons of dry hay per acre. All of the Sudan was cut three times and furnished a considerable amount of green pasture be- tween the time of the last cutting and the first frost in November. Small grains: During the fall of 1915 several varieties of wheat arid rye were planted, but all were either destroyed by winter killing or by rabbits, except one plat of rye. The rye had a very meager stand and was not worth harvesting. All the small grains were considered complete failures. SILOS During the year a 40-ton cement silo was constructed on the farm. This is the second silo to be built, the first one being a pit silo built the year before with a capacity of about 35 tons. GENERAL CONCLUSIONS Plowing should be done in this locality in the fall or early winter. Spring crops should be sown as early as late frost will permit in order to take advantage of the winter moisture that has been retained in the soil. Locally grown seed should be used on account of its acclimatiza- tion to local conditions. 266 Twe;nty-seventh Annual Report SULPHUR SPRING VALLEY DRY FARM The work on the Sulphur Spring Valley Dry Farm proved suc- cessful this year in demonstrating that feed can be produced in sufficient quantities to carry on a system of livestock farming. This success was due largely to the use of selected varieties of crops which have been proven adapted to this region, and to the copious rainfalls which were well distributed during the entire growing season. WATER SUPPLY The farm is operated so as to take advantage of any flood waters that may come upon it. It is also supplied with a small pumping plant which to a limited extent can be used to supplement dry farming operations. Nine inches of rain fell on the place during the months of July, August, and September. The greater portion of this water fell during July and August in eight or ten showers, which thoroughly distributed it over these two growing months. CROPS Small grains: During the fall of 1915 sixteen varieties of wheat, and one each of oats, barle}^, spelt, emmer, vetch, and rye were planted on one-quarter acre plats. Nearly all of these varieties with the ex- ception of vetch came through the winter with a rather imperfect stand and showed promise of making grain, but upon the advent of warm Vv'eather the lesser migratory locusts appeared and completely destroyed the crops. Grain sorghums: The work with the grain sorghums — kafir, feterita. Dwarf and Standard milo — was largely a test to determine the proper date of planting. The best results from these tests were ob- tained with the March 17 planting of Dwarf Black Hulled White kafir. This crop produced 10,530 pounds of green silage per acre on a two-acre plat. Weights for the quantity of grain gave an estimate of 4001 pounds of grain in the head per acre. This was more than any of the other grain sorghums planted at any date. Feterita gave fairly good re- s>dts with the July planting. This crop harvested 9504 pounds of green silage and an estimated yield of 2052 pounds of grain in the head per acre. The size of the feterita plat that gave these results was one-third of an acre. None of the plantings made on April 17 and May 18 produced a crop of sufficient amount to make those dates of planting practicable. With Dwarf kafir for March planting and feterita for Arizona Agricultural Experime;nt Station 267 planting- in July after the rains appear, the Sulphur Spring Valley farmer is amply provided with crops of this kind. The above crops of kafir antl feterita were grown on some of the poorest soil on the farm. This particular portion of the farm is underlaid with clay and caliche at a depth of 18 to 24 inches and the water holding capacity of the soil is very low. In some seasons this portion of the farm receives copious floodings from an arroyo that comes down from the country above, but this year no such flood water was obtained. Saccharine sorghiiiiis: Club-top cane and Black Amber cane were each planted on three dates: April 15, May 18, July 21, respec- tively. The Black Amber cane made a very poor showing in all of the plantings. The Club Top cane produced two tons of green silage per acre with the April 15 planting and 3.5 tons with the July 21 planting. July planting, however, was immature when harvested. The grain sorghums are superior to the canes for silage purposes, and, since the results indicate greater tonnage from the grain sorghums, there is little reason for the growing of the forage canes. Corn: Six varieties of corn were tested. Plantings \Yere made with each variety on three separate dates: April 16, May 15, and July 22, respectively. The April and May plantings resulted in very im- perfect stands on account of insufficient moisture in the seed bed ; while the July 22 planting did not afiford ample time for complete maturity of the larger growing varieties, such as Mexican June. The Mexican June vvith each date of planting was superior to the other varieties tried, and appears to be a very excellent variety to grow under these dry farming conditions. The other varieties used in the trials were White Flint, Freeds, White Moqui, Mohave, and Papago Sweet. The April plant- ings of Mexican June yielded four tons of green silage per acre, and an estimated yield of 2490 pounds of grain in the ear per acre. The July planting of Mexican June was immature at the time of harvesting, but yielded 11,520 pounds of green silage per acre. The size of the corn plats varied from one-half to one acre. The smaller Indian corns did not equal the yields of the larger growing varieties this year, but in all probability in years of limited rainfall they would give returns when the larger growing corns would be a failure. Canada field peas: Three acres of Canada field peas were sown February 29. The crop was a failure for two reasons, — heat and grass- hoppers. The moisture conditions were good and the peas germinated well giving a perfect stand. When the peas reached a height of seven inches they stopped growing and stood at this size for several weeks imtil the grasshoppers eventually devoured the crop. 268 Twenty-Seventh Annual Report A winter legume is highly desirable in this region for soil building purposes, and more work should be done along the line of testing out either field peas or some other legume that could be used as a green manuring crop. Tepary beans: Seven acres of Tepary beans were planted July 17. The beans were harvested October 5 and gave a yield of 752 pounds of reoleaned beans per acre. After the beans were harvested Fig. 5. Tepary beans on a windy day at the Sulphur Spring Valley Dry Farm. Yield, 752 pounds per acre. the soil was left in excellent condition. All that was then necessary for the planting of small grains in this field was double discing and drilling. Pink beans: Two acres of pink beans were planted on July 19, on land of the same character as the field of Tepary beans and received the same treatment in every respect as the above crop. Pink beans harvested October 22 yielded 208 pounds of recleaned beans per acre. Cowpeas: Two varieties of cowpeas, Whippoorwill and Black- eyed, were planted July 19. The yields for the two varieties were 51 pounds of Whippoorwill peas per acre and 335 pounds of Black-eyed peas per acre. The Whippoorwill peas made much heavier growth of vme, but did not wholly mature its full crop of seeds. The Black-eyed pease were earlier and yielded a mature crop, but the vines were not so luxuriant. The Whippoorwill peas promised to be the best variety Arizona Agricultural Experiment Station 269 for green manuring purposes. A crop of Whippoorwill peas could be planted to take advantage of summer rains and plowed under in the fall. Sudan grass: Sudan grass was planted on three dates: April 15, May 18, and July 21, respectively. The April and May plantings gave a very imperfect stand which was further damaged by grasshoppers. The July planting was on very thin soil underlaid with caliche at a depth of about 12 inches. The yields in all the plantings were very un- satisfactory, less than a ton per acre being harvested from the April and July plantings, and only about 600 pounds per acre from the May planting. Two cuttings were made from each plat. The results obtained from the work with Sudan grass should not be taken as evidence that this crop cannot be made to yield profitable returns on this dry farm. The performance of individual plantings more favorably located as to soil conditions and the appearance of portions of the plats where the early planted seed found sufficient moisture to germinate, indicates that if properly handled, Sudan will become a very valuable forage grass for this region. conclusions The short season crops must be delayed until the coming of the summer rains in July. The dry farmer must farm with the moisture as the limiting factor ; and to conserve that moisture and take advantage of it at the proper time is his main problem. This year's results would indicate that Dwarf kafir, Mexican June corn and Sudan grass planted in March on fall plowed ground ; feterita. Club-top cane, Tepary beans, cowpeas, and a second crop of June corn planted in July on a previously prepared seed bed moistened by the first rains of the summer, and small grains sown in October on the Tepary bean ground, would furnish ample feed for the livestock farmer, and at the same time give a crop of beans or wheat to be placed on the market for cash. J. F. Nicholson, Agronomist. H. C. Heard, Assistant Agronomist. BOTANY Rainfall for the year ending June 30, 1916, was generally up to the average or somewhat above, for the State as a whole. This was true both as concerns the summer and the winter rainfall. As usual most of the summer precipitation took place during July and August. October and November were dry months and there was little growth on the ranges after the middle of October. The long dry fall was unusually favorable for the natural curing of the bunch grass growth, and also enabled stock to consume the heavy crop of mesquite beans before this could be damaged with moisture. The winter rains were abnormally heavy during December and January and lighter than the average in February and March. As is well known, rainfall on the ranges before January 20 is of less value than that which comes later, and when heavy it may prove even detrimental. The heavy rainfall of the earlier winter months caused considerable erosion on the ranges and also serious floods in many of the river val- leys and washes. Besides this, it damaged greatly the bunch grass feed on the ranges through leaching. And, finally, it came at a time when the temperatures were too low, even on the warmer desert ranges, for active winter annual growth. When the temperatures were more favor- able, in February and Anarch, the rainfall had dropped off greatly with the result that the growth of the late winter and spring forage was not as heavy as it would have been with a more timely distribution of the rainfall. The rainfall on the small range reserve, near Wilmot, Ari- zona, which is typical of southern Arizona fanges at the lower altitudes, may be cited as an example of this. The total precipitation for this area for the year ending June 30, 1916, was 13.95 inches, or about 2 inches above the average. Of this 5.65 inches fell during the summer period, July to October inclusive, and 8.17 inches in the winter season, December to April inclusive. Of the latter, 6.22 inches came during December and January, which left but 2 inches of moisture to mature the growth begun in the winter season. Naturally, this growth was shorter than it would otherwise have been. ROOT-ROT DISEASE During the year, Mr. Uphof and the writer devoted some time to the study of root-rot of alfalfa and fruit trees, both in the field and in the laboratory. This work led to the isolation of several different or- Arizona Agricultural Expe:riment Station 271 ganisms or fungi, of which one was a species of fiisariiiin. This fungus was present in practically every culture made from roots of plants that had died from the disease known as root-rot, and it is believed to be one of the organisms causing this disease. This is apparently the same species of fusariiiin that Dr. ^McCallum studied several years ago at this Station, in his work on root-rot. This fungus develops commonly in great quantity as a white filamentous growth on roots of plants that have recently died, when these are washed and placed in a moist, sterile chamber. It is quite easily obtained as a pure culture and grows readily in a large number of prepared media. With several trials Mr. Uphof did not succeed in inoculating healthy seedling alfalfa plants with cul- tiires of this fungus. This inoculation w^ork was done late in the season when the fungus was quite inactive, which may explain the failures, . Unfortunately, it was necessary to discontinue this work last June after the departure of ]\Ir. Uphof. As is well known, root-rot disease is widespread in our State and causes serious losses for the alfalfa grower, orchardist and gardener. Accordingly, this study should be completed at an early date so as to open the way for a possible economic control of the disease. publications Bulletin Xo. 79, Cold Resistance in Spineless Cacti, was com- pleted in July and is now in press. This work is an attempt to deter- mine the factors which influence resistance to cold in spineless cacti and completes an Adams' fund project that was outlined three years ago. Spineless cacti have not proved very hardy in Arizona, which fact was noted in Bulletin 67 of this Station. This statement led to consider- able inquiry and correspondence and was partly responsible for the present bulletin. For this work spineless cacti that were considered hardy, were secured from several sources and, with others that were known to be injured with a few degrees of frost, were planted in the introduction garden at the University Farm in the spring of 1913. The soil was loamy in character and the plants were given moderate care in the way of irrigation and cultivation. The following varieties of platopuntias were among the more im- portant of the ones planted: Opuntia Hens indica from Malta; 0. Hens indica from Sicily; Opuntia sp. Burbank Special, regarded as very hardy; O. fitsicaulis, a slender-jointed spineless pear; O. castillac, a spineless Mexican cactus growing in Tucson gardens; and 0. EUisiana, secured from Mr. B. R. Russell, San Saba, Texas. Careful notes were kept on these plants concerning their rates of 272 Twenty-seventh Annual Report growth, and relative resistance to summer and winter temperatures. It was observed in brief that Opuntia castillae and O. ElUsiana made less growth than the other species, but that they were hardier to winter temperatures. With these species growth usually ceased in October while the others often continued growth until severe frosts began in November. Naturally, the tender half-matured joints were killed with the first heavy frost. In the summer of 1915, Mr. J. C. Th. Uphof, then assistant in botany in the department of biology, made laboratory studies, morpho- logical and physiological, of joints of these plants in order to determine the factors of cold-resistance in cacti. Mr. Uphof found that the varieties of spineless cacti having relatively thick integuments may v;ithstand a low temperature for a short time with little or no injury while those having thinner integuments would be injured. He also . found that the collecting and freezing of water from the cells in the intercellular spaces during low temperatures is not in itself harmful to the plant. Also, that the protoplasm of the cell is not poisoned with the concentration of the cell-sap solution as a result of at least part of the water of the cell being withdrawn to the intercellular spaces and frozen. Mr. Uphof concluded that with normal cactus plants resistance to cold is inherent in the protoplasm, and for this reason some varieties can endure more frost than others. Mr. Uphof's work checked quite closely with observations made by the writer relative to low temperatures in winter. He found that Opuntia castillae and 0. EUisiaiia were more resistant to cold than any of the other species and that Opuntia ElUsiana was considerably hardier than 0. castillae. Mr. Uphof determined that Opuntia castillae would be injured with a temperature of 6.8 degrees F. During the winter of 1912-1913, it was severely frozen back on the University grounds with a temperature of 6 degrees F., and in December. 1916, it was injured at the University Farm with an estimated temperature of 9 degrees F. The literary work of this bulletin was done by the writer, the reason for this being stated in the publication. Timely Hint No. 117, Vines for Shade and Ornamental Planting, was written to meet a growing demand for information on this sub- ject. This leaflet discusses briefly the value of vines for general plant- ing and includes a list of the hardier species, both evergreen and de- ciduous, that are quite generally planted. Short descriptions of the varieties are given together with methods of cultivation. Mnes are among our most ornamental plants. They are planted more in the Southwest than in other parts of the country, partly because of our Arizona x\gricultural Expkrimunt Station 27Z stronger sunlight and aridity, and also the quick shade which they supply. The following species were recommended for planting over the State : tive-leaf ivy or Virginia creeper (Parthenocissus vitacea var. macrophylla) ; Japanese ivy (Parthenocissus tricuspidata) ; Japanese honeysuckle (Loiiicera jdponica) ; English ivy (Hedera helix) ; Arizona grape (Vitis arizonica) ; trumpet honeysuckle (Lonicera sempervirens) ; silk vine (Pcriploca graeca) ; Chinese wistaria (Wistaria chiensis)/, Chinese trumpet creeper (Tecoma chiensis) ; blue passion flower (Passi- flora cacriilea) ; Japanese virgin's bower (Clcmatic paniculata) ; west- ern virgin's bower (Clematis ligiisticifolia;) native hop vine (Humulus lupuliis var. ncomexicana). Timely Hint No. 118, Crown Gall, deals with the well-known disease of orchard trees and suggests means for its control. Severe losses have resulted to Arizona orchardists from crown gall, and it may be looked for now in practically every agricultural community in the State. Recent studies have shown that in addition to deciduous fruit trees, hops, grapes and cane fruits, crown gall attacks roses, chrysanthe- mums,. Paris daisies, walnuts, white poplars and similar shade trees be- sides field crops like sugar beets and occasionally alfalfa. Nurseries have played an important part, often unconsciously, in the spread of this disease. In the light of better information concerning the infec- tious nature of crown gall, and with stringent state inspection laws, there will be less danger than heretofore of introducing crown gall in one's orchard. However, the orchardist and farmer should exercise great care in purchasing nursery stock and insist that it be inspected properly by the state authorities. STUDIES IN THE FLORA This department is assisting the forest service in this State to identify the more important plants, both woody and forage species, that grow on our forest areas. It is also cooperating in a like manner with the Bureau of Biological Survey, Washington, D. C, relative to their work of mapping the life zones of Arizona. More than 200 plants were determined for the Coconino National Forest last summer and smaller lots for other of the forest areas. Thus far 180 species have been identified for the government biological survey work. Most of these plant specimens are deposited ultimately in the herbarium of the University for future reference. This work requires a considerable outlay of time, but it is invaluable since it enables the Botanist to be- come better acquainted with plants from widely separated localities in the State and their distribution. It also helps to make more nearly 274 TwENTY-siSviiNTH Annual Report complete the work on the flora. It has been the means of bringing to notice a number of species that heretofore were not known to occur in the State. In addition to this, the writer practically completed during the year a study of the native Ptcridophytcs or fernworts, Chcnopodiaceae or Goosefoot family which includes the saltbushes, and Amaranthaceae or Tumble-weed family. Studies were also made on the trees of Ari- zona which added several more species for the State, and work was begun on the grasses. Besides the above, two classes were taught each semester. Six weeks of the past summer was spent in field work, principally about Prescott, Flagstafl:', and the Grand Canyon. This trip was made by automobile with a camping outfit which made it possible to stop wherever interest demanded. Much valuable information was secured relative to grazing, carrying capacity of ranges, and poison weeds. The distribution and abundance of the more important plants was also noted. Quite complete plant collections were made at the Grand Canyon and Prescott. A careful study was also made of the shade and ornamental plants growing most successfully above altitudes of 5000 feet. The information on cultivated species is being included in a bulletin on the shade and ornamental plants of Arizona. MISCELLANEOUS The writer read a paper at the meeting of the American National Livestock Association, El Paso, Texas, last January, entitled The Practical Application of the Ferris Stock-raising Homestead Bill to Our Western Grazing Ranges. This was published in the Proceedings of the Nineteenth Annual Convention of the American National Live- stock Association, 1916, pp. 116-120. This law was enacted recently, and the stockman may now take up a section of arid grazing land for a homestead. J. J. ThornbEr, Botanist. HORTICULTURE The major part of the Assistant Horticulturist's time has been occupied in teaching. Extension work occupied twenty-two days' time. Experimental work with lettuce, beans, sweet potatoes, and egg plants occupied the remainder. lettuce; The cantaloupe growers of Salt River Valley, in casting about for a crop to occupy their time and land during the winter months, first began to take serious interest in lettuce during the winter of 1914-15. The efforts of most of the growers this season were discouraging from a financial standpoint. The two most serious difficulties were in the matter of season and marketing. The writer, therefore, took up the task of aiding in the solution of these problems. The questions which arose were : 1. Wdiat methods of packing, loading, and refrigeration will in- sure the safe arrival of lettuce on the market? 2. What is the best variety for Salt River Valley ? 3. What cultural methods would resuh in earlier maturity of the crop? The Glendale growers, who are most vitally interested, solved or partially solved most of the shipping problems themselves during the season of 1915-16. They found that lettuce reached Eastern markets in excellent condition if the following precautions were observed : 1. Pack crates with a 3-inch bulge before the lid is put on. 2. Precool the packed lettuce in the cold storage room of the local creamery for 48 to 60 hours (or until a car is made up). 3. Load cars before daybreak. 4. Load the car only two-thirds deep. 5. Leave ventilating space between rows of crates in the car. At the writer's suggestion Mr. S. B. Tatum, of Glendale, shipped a sample of lettuce to A. Steinfeld & Company, Tucson. The manager of the grocery department of this store suggested that the shipper line the crates with paper to prevent contamination in transit. Mr. Tatum acted upon this suggestion by lining the crates in a part of a car consigned to a commission merchant in Kansas City. Word came back from this merchant. "Line all crates hereafter. Lined crates bring 25 cents a crate more than unlined." Work to decide the relative merits of different varieties was begun at the Yuma Date Orchard in the fall of 1915. The following varieties 276 Twenty-seventh x\nnual Report were grown : New York or Los Angeles, Large Hanson, Denver Mar- ket, Iceberg, Alay King, Early Curled Simpson, Grand Rapids, White Paris Cos, Salamander, California Cream Butter, Big Boston, and White Summer Cabbage. Work at the Phoenix Farm the same year was designed to determine the value of manure in accelerating the maturity of the crop. Following the first year's work an acre of ground at the IMesa Farm is now in variety and cultural experiments to determine (1) If any variety of the crisp type of lettuce is superior to the New York for market purposes; (2) If there are marked dififerences in different strains of New York; (3) What quantity of manure is desirable for the crop; (4) Can cotton seed meat be substituted for barnyard manure as a fertilizer; (5) Which method of culture is to be preferred — one single row on each ridge, double rows to the ridge, or flooding the crop. This work up to this time offers the following conclusions : 1. The crisp type of lettuce represented by New York, Iceberg, and many other varieties are to be preferred for Arizona conditions to the butter head type represented by Big Boston, Tennis Ball, and many other varieties. 2. Drilling the seed makes thinning easier than dropping the seed in hills. 3. Thinning can be done better and cheaper when the plants are very small. 4. Crowding in the row or delay in thinning delays maturity. 5. A heavy soil lacking enough organic matter to make it crum- ble can delay the maturity of the crop several weeks. 6. Applying rotted manure in large quantities ( 10 to 20 tons per acre), or plowing under a cover crop is necessary for a profitable crop in most soils. 7. It takes about 90 days of good growing weather to mature the crisp type of lettuce. 8. Poor seed, poor soil, cold weather, delayed thinning, and poor cultivation will increase this time. ARIZONA CLIMATE AND BEAN ANTHRACNOSE In the spring of 1916, Mr. A. N. Brown, editor of the Fruit Belt, Grand Rapids, Michigan, wrote that he had heard that anthracnose did not aft'ect beans in this State. If this was true he thought Michigan growers would profit by using seed grown in Arizona. The writer was detailed to study the question. Through the kindness of the W. A. Burpee Seed Company, of Philadelphia, samples of 36 varieties of beans were donated to the Arizona Agricultural Experiment Station 217 Station, and were planted on the Sulphur Spring Valley dry farm near Cochise. Later jNlr. Brown sent some diseased bean seed. The diseased seeds were planted in the middle of the variety block so that if the disease could develop in this climate it would have a good chance. Professor J. G. Brown of the University made examinations of suspected material during the growing season and reported that he found an organism which looked like the anthracnose ( Collet otrichum Lindcmuthianum) , but no spores could be developed. After the crop was harvested Professor Brown was unable to obtain any cultures from the beans produced from the infected seed. Of the varieties grown at Cochise all but the very late ones matured a fair crop of seed, showing that bean seed can be grown here if there is any superior quality in seed so grown. storage of sweet potatoes Since the sweet potato is an important garden crop in Arizona, the writer concluded that a study of methods of storage suited to Ari- zona conditions would be beneficial to the truck farmer. In one trial the potatoes were picked in the ordinary way, carried in sacks to the barn, and were spread in thin layers between straw. In the other trial only sound potatoes were chosen for storage. These were placed in crates in a room heated with an oil heater, and then piled between layers of straw as were the first lot. A report on the percent which keeps will be made in the spring. KEEPING EGGPLANT Although the eggplant is a vegetable of minor importance, the presence of summer vegetables on our tables in the winter season is generally welcome. The deterioration of the eggplant is due largely to evaporation from the skin. Noting this fact the writer October 25 dipped eight eggplants in melted parafiin, and hung them up by the stem. Three of the eight eggplants decayed from a brown rot. The other five were in good condition December 16 when one of the them was cooked in the ordinary way, the quality being as good as one direct from the vine. The other four are at this late, January 25, apparently in excellent condition. It may be that the rotting of the fruits can be prevented by disinfecting the surface before coating with paraffin. No rot developed which had not started within the first two weeks. The method appears to be a practicable one for home use. S. B. Johnson, Assistant Horticulturist. PLANT BREEDING Owing to the fact that a considerable part of the time of the head of the department was devoted to the additional duties which devolved upon him as acting Dean and Director of the College of Agriculture and Agricultural Experiment Station, and as a result of interruptions occasioned by other changes in the Staff, it was considered advisable to confine the work of the department for the year to the breeding of wheat, alfalfa, and the grain sorghums. The w^ork with beans and sweet corn, and the transpiration studies with alfalfa were postponed. WHEAT The total acreage of experimental wheat plots at Yuma was 4.08 acres. The total yield of grain on this area was 7S62).h pounds of cleaned grain. The average yield per acre was 30.9 bushels. The alkali spots of the Dyer block reduced the yield to some extent, but in no place was the alkalinity strong enough to entirely prevent the plants from maturing seeds, except in two or three small places of negligible area. The growth on at least one-eighth acre was somewhat dwarfed on account of alkali. Some of the plots lodged badly while the plants were in bloom, and a high percentage of heads on these plots was completely sterile. Cold weather and a light frost came while some of the earlier strains were in bloom, and prevented them from setting a full crop of seed. Owing to these abnormal conditions of weather during the growth of the crop, the yields of the different varieties in 1916 were very different from yields obtained in 1915. The highest yielding variety of 1916 was the Early Baart, making an average of 49.46 bushels per acre, while one plot of this variety yielded at the rate of 56.98 bushels per acre. This strain has been developed from a head selection made from a large field plot, and is proving to be very productive in the large test plots. The average yields for all the large test plots are given in Table IX. TABLK IX. WHKAT VARIETIES AT YUMA, 1916 Name of variety Early Baart Sonora White Algerian. Red Algerian . . . Yield per acre bushels 49.46 39.08 29.00 26.16 Arizona Agricultural Experiment Station 279 In addition to the large test plots, 65 pedigreed races were planted in increase plots. Each of these races was selected from the best head rows of the previous season's crop. The object of this experiment was to increase the seed from these excellent races, and to further test their yielding capacity when planted under practical field conditions. Al- though some of these races suffered severely from a late frost, and therefore made low yields, others outyielded the original races from which they were selected. A selection of Turkey Red wheat produced 51 bushels per acre, while the original stock from which this selection was made produced only 43.2 bushels in 1915. A similar gain in yield was obtained from nine other selections. The abnormal conditions of the spring weather,- such as cold weather and late frosts, make it nec- essary to repeat this series next year. The wheat hybridization project has been continued this year, and data on the third generation has just been completed. Reciprocal crosses of the following varieties have been studied : Early Baart x Macaroni, Sonora x Macaroni, Algerian Red x Macaroni. The object of this project is to combine the hardiness, disease re- sistance, and high yielding qualities of the macaroni with the high mill- ing quality of the bread wheats. A very exhaustive study of heredity in wheat has also been made. About twenty-five thousand hybrid wheat plants were grown at Yuma and harvested in the spring of 1916. Care- ful individual plant records were made of the following characters : Date of first head, height of plant, date of maturity, strength of straw, and rust resistance. The heads of each plant were harvested in a sepa- rate bag and the whole lot was shipped to Tucson where laboratory notes were taken on the following head characters : Number of heads, the dimensions of the largest head of each plant, length of awns, and color of chaft". A very extended study of sterility has been planned and carried forward during the past two years. This is one of the most difficult problems with which the plant breeder has to deal in producing high yielding strains. ALFALFA The alfalfa plots on Land 1 1 at Yuma were continued through the year 1916. Table X gives the total yields per acre from these plots. Table X shows that the Peruvian alfalfa leads in yield, as it has done during the two previous years. It should be said that Plot 39b of the Peruvian is not thoroughly level. About one-third of this plot is too high to receive the same quantity of water as the other plots. This accounts for the low yield on this plot. A seed crop was also 280 TWENTY-SKVKNTH ANNUAL REPORT taken from these plots. From the seed crop taken in 1913. these trial plots were transferred to the Mesa Farm, and the high yielding strains were planted in one-fourth acre plots. TABLE X. YIELDS OF ALEALFA AT YUMA, 1916 No. of plot 39a 11 22 24 39b 27 35 41 39c Name of alfalfa Hairy Peruvian Italian Baltic (from Colorado) Algerian type (Bagdad).. Algerian (Oued Rirh) Hairy Peruvian Turkestan Siberian (Turkestan type) French (European type) . . Hairy Peruvian Total yield pounds per acre 17772 16777 15384 15751 12121 13352 12151 13943 14476 16657 Seeds were taken from all the pure lines of alfalfa growing at the Evergreen Nursery, anl these plots have been discontinued. Twenty- six plant selections were made from these plots and the seeds from these plants were planted in rows at the Mesa Farm last fall. GRAIN SORGHUMS As a preliminary test for securing good foundation stock for breeding work with the grain sorghums, sixty head selections of milo, feterita and kafir were planted at the Yuma Date Orchard in July. Approximately one hundred plants were grown from each selection, and the following notes were taken: Date planted, date up, date thinned to one plant in hill, date first head, date full head, date ripe, number of heads per plant, weight of heads from each selection cut not over one and one-half inches below base. These data will be used as a basis for further selection in breeding for higher yielding strains and more desirable types. A total area of one and one-eleventh acres was planted to these selections, and a total yield of 5758 pounds of head grain was obtained. Geo. F Freeman, Plant Breeder. W. E. Bryan, Assistant Plant Breeder. ANIMAL HUSBANDRY Investigations in animal hnsbandry have been conducted along five different lines : (1) Sheep breeding experiments ; (2) feeding Tepary beans to hogs; (3) supplmenting alfalfa hay for milk production; (4) Ostrich investigations; and (5) study of the variovis systems of live- stock farming in Arizona. she;ep investigations The flock of sheep located in Salt River Valley has undergone considerable improvement this past year. All animals that were of inferior type or unsatisfactory in mutton, v^ool, or other qualities were discarded. The present flock has been materially decreased in numbers. Wool study: The weights of wool of the various crosses of sheep have been studied during the past year. Instead of averaging the entire number of clips of wool of the different crosses as has been done in previous reports, the different clips of wool were compared with each other and with those of other crosses. This was necessary, for the Tunis-Native and the Hampshire-Tunis-Native crosses have many more old sheep than any other. It has been observed that the first clip is usually very light while the second and third clips are much heavier. Some of the crosses give their heaviest fleece at two years of age, while others give their heaviest clip at three yars. Still others have seemingly increased in weight of wool as they grew older. The sheep of some of the crosses have had three clips ; and in comparing their wool only the first three clips were taken into consideration. Table XI shows the weights of wool according to clips of the various crosses for a period of six years. The first clip averages the lightest of all, while the weight of wool gradually increases until the fourth and fifth clips which are slightly lower, but the sixth clip shows a marked increase over the others. It should be noted that before the sixth clip was taken most 282 Twenty-seventh Annual Report table xl weight of wool by clips and crosses Cross T 1 T N 2 2 T HN 2 T 4 S 4 N 2 T 4 T 4 N 2 S 4 4 1 s N 2 S 2 T N 2 S 4 4 H T N 2 H 4 N 8 8 2 H 2 T N 1st clip o 4 days the pigs were fed in a dry lot. Lot 1 received rolled barley and water, while Lot 2 received rolled barley, Tepary beans and water, the grain being mixed in equal proportions by weight. Rolled barley is not con- sidered an especially palatable food for hogs, and it is unbalanced, being deficient in protein. On the other hand the beans are rich in protein, and according to its composition should be well suited for balancing the rolled barley. It is thus shown that Lot 1 was fed a more or less unbalanced ration while Lot 2 was fed a better balanced ration. The pigs were fed twice a day throughout the experiment. The amount given Lot 1 was regulated according to the consumption of the feed by the pigs receiving the mixture in Lot 2. Each lot was started by giving it five pounds of the feed daily or approximately L66 pounds per hundred pounds live weight. At the outset of the experiment the pigs in Lot 2 did not take kindly to the Tepary bean mixture, and did not make satisfactory gains. They carefully picked out the rolled barley from the feed, and did not consume much of it. The next en- deavor to induce the pigs to consume the Tepary bean mixture was by grinding the rolled barley and the cracked beans finely and mixing them thoroughly. This did not have the desired effect as the pigs refused to eat the mixture and 12^^ pounds were weighed back. The feed was made into a wet mash, but this did not increase its palatability. The pigs in Lot 2 were apparently hungry and losing weight; they became restless and rooted more in the ground than those in the other lot. Fifteen days after beginning the experiment the beans were cooked and mixed with rolled barley and the pigs ate them greedily. After this the beans were eaten with relish, and it did not make much difference whether they were ground or whole if cooked. It was found that by soaking the beans overnight and cooking them about 30 minutes they were improved in palatability. Lot 1 Lot 2 No. of (lavs in test 64% 64 1/2 Total feed consumed 365 pounds 351.5 pounds Feed consumed dailv per animal 2.81 pounds 2.80 pounds Total cost of feed. .". $ 5.48 $ 7.91 Total gains 64 pounds 42 pounds Average daily gain 99 pounds .65 pounds Food required per 100 lb. of .gain 570 pounds 837 pounds Cost to produce 100 lb. of gain $ 8.56 $18.83 The pigs in the two lots were given the same amount of feed, namely, 365 pounds, but 12^' pounds were weighed back from Lot 2, before the beans were cooked. After this time the pigs consumed the same amount of feed which was gradually increased until each lot con- 288 Twenty-seventh Annual Report Slimed 8 pounds of feed at the end of the experiment. The following is a summary of the results of this test : The hogs consumed about the same amount of food daily, but the cost of the feed was much higher in Lot 2 than in Lot 1, owing to the high market value of the Tepary beans. When rolled barley was fed, 570 pounds were required to produce 100 pounds of gain, while 837 pounds of the mixture of Tepary beans and rolled barley were re- quired to produce this amount of gain. No doubt the inferior start which Lot 2 had in the beginning of the experiment militated against either large or economical gains. However, it is significant to note that the gains were greater from the lot receiving rolled barley than from the same amount of the mixed food. It is further interesting to note that the hogs receiving the mixed food or balanced ration only gained 42 pounds, while the others gained 64 pounds. This is an in- crease of 50 percent in the gains from the same amount of food. The cost of producing 100 pounds of gain was $8.56 for Lot 1 and $18.83 for Lot 2. Certainly one can not hope to make economical gains from feeding Tepary beans valued at 3 cents per pound to hogs. EEFECT OE ROLLED BARLEY ON ALFALFA-BEET PULP RATION FOR MILK PRODUCTION For the past few years the University has been feeding dried beet pulp and alfalfa hay to the dairy herd. Believing that it would be more economical to replace a part of the beet pulp with some grain, a test was run during the spring of 1916 to determine whether it would pay to feed equal parts of rolled barley and beet pulp rather than beet pulp alone as the concentrate part of the ration. Beet pulp is cheaper in price than rolled barley, it costing only $1.35 per cwt., while the latter retails at $1.70 per cwt. It has given splendid results as a feed for dairy cattle, and it is usually cheap in price compared with other feeds. Beet pulp and rolled barley are about the same in percentage of digestible nutrients, the barley being a little higher in digestible crude protein and fat, but lower in carbohydrates. Since alfalfa is low in carbohydrates but relatively high in protein, it furnishes the greater part of the protein required in the ration. Where figured at $14.00 per ton, alfalfa hay furnishes nutrients most cheaply, the beet pulp ranking next and the barley last. To get a fair test on the rations, ten of the cows were divided into two lots, balancing the lots as nearly as possible according to breed, Arizona Agricultural Experiment Station 289 period of lactation, and amount of milk given. Owing to the limited number of cows, it was impossible to balance the lots perfectly, but they were even enough to compare favorably. One lot was fed molasses- dried-beet pulp as the sole concentrate, while the other lot was fed a mixture of equal parts of rolled barley and molasses-dried-beet pulp, both lots being fed at the rate of about one pound of the concentrate to four pounds of milk produced. The alfalfa was fed to both lots alike, and they were given what they would clean up well. The rations were alternated, so that the lot receiving rolled barley during one period did not receive it during the following period. The actual test covered a period of 68 days. In Table XVI the data are arranged according to feeds fed, so that the results of each ration can be readily compared. TABLE XVl. ALFALFA, BEET PULP, ROLLED BARLEY VS. ALEALEA, BEET PULP EOR MILK PRODUCTION Milk pro- duced Cost of ration Feed cost oer 100 lb. milk Fteed cost per gal. •nilk \'alue of milk at 25 cts. per g-al. Profit over cost of feed pounds dollars dollars cents dollars dollars Lot fed alfalfa, beet pulp and rolled barley Lot fed alfalfa and beet pulp Difference caused by bar- ley 7316.2 6993.4 322.8 91.75 87.00 4.75 1.25 1.24 .01 10.7 10.7 .0 212.68 203.29 9.39 120.93 116.29 4.64 A greater amount of milk was produced when barley was substi- tuted for half the beet pulp. Barley being higher in price than sugar beet pulp, increased the cost of the ration, but enough more milk was produced when it was fed to make the feed cost per 100 pounds or per gallon of milk about the same as where beet pulp was the only con- centrate fed. Valuing the milk at 25 cents per gallon, that produced by the lot fed barley was worth $212.68 as compared with $203.29 when no barley was fed. Barley caused an increase of $4.75 in the cost of the ration, but it caused an increase of $9.39 in the value of milk produced, making $4.64 more profit over cost of feed than where beet pulp was the only concentrate fed. The cows relished the feed more where barley was mi.xed with the beet pulp, and they cleaned it up better. Some of the cows would refuse to eat the beet pulp alone after becoming accustomed to having rolled barley mixed with it. The cows held up a little better in weight during- the time that barlev was substituted for part of the beet pulp. 290 TwENTY-sEvKNTH Annual Report OSTRICH INVESTIGATIONS During the past year ostriches have been fed an average of three pounds of alfalfa hay, one potmd dried beet pulp, and one pound of grain daily. The grain ration has consisted chiefly of whole wheat, but milo maize and barley have also been fed. At the present time there are fourteen old ostriches, two yearlings, and six spring chicks. The heavy snow storm of the \\'inter caused all but two of the strongest yearlings to die. It thus seems that young ostriches can not endure much cold. This snow storm did not seem to injure the older birds. A careful record was kept of the eggs as they were laid. Table XVII gives the egg record for each hen arranged according to breed for the years 1915-1916. TABLE XVII. EGG RECORD FOR EACH HEN ARRANGED ACCORDING TO BREEDING FOR THE YEARS 1915 AND 1916 Breed Hen Eggs laid Average weight of eggs Total weight of fresh eggs 1915 1 1916 1915 1916 1916 1 grams grams grams South African South African South African South African Average. . . 1410 2071 2105 2136 11 34 7 20 on 25 34 26 28.75 1279.6 1489.3 1496.5 1510.7 1440.3 1406.75 1483.50 1566.80 1571.40 1507.11 42,202 37,088 53,274 40,858 43,355.6 Nubian Nubian Average. . . No No. 2170 12 41 26.5 16 35 25.5 1473.0 1704.9 1588.95 1585.0 1608.9 1596.95 25,360 56,313 40,836.5 Crossbred . . . Crossbred . . . Crossbred . . . Average. . . 2305 2180 2292 21 41 5 37.33 31 1 1485.7 33 ■ ! 1612.7 34 1 1761.6 32.67 1620.0 1542.4 1600.8 1801.0 1648.0 47,816 52,827 61,234 53,959 Average for flock 22.22 29.33 1536.91 1579.43 46,330.3 Number of eggs laid by each hen: The diflferent hens laid from 16 to 35 eggs each. With the exception of the old hen, no number, the range was 25 to 35 eggs for the individual hens. The average number of eggs laid was 7.11 greater than the previous year, and there was much less variation in the number laid by the hens. The average number of eggs laid by the flock was 29.33. The three cross-bred hens laid an average of 32.67 eggs per bird, while the South African gave the next highest average, 28.75, and the Nubian 25.5 eggs per bird. It so happened that the hen that laid the fewest eggs was a Nubian, and also the one that laid the greatest number of eggs was from this breed. Arizona Agricultural Experiment Station 291 Since there was a greater range in the birds of the same breed than between the average of the cUfferent breeds, no definite conclusion is justified with regard to the breed of the birds as affecting the number of eggs that they lay. Az'cragc zveiglit of eggs laid: There is remarkable similarity be- tween the general appearance and weight of eggs laid by the same hen over the two years. The ranking of the birds was very similar to that of the previous year. Three of the birds laid eggs with a lighter average weight while six of them gave eggs that averaged from 27.15 grams to 112 grams heavier than that of 1915. Table XVIII indicates the increase or decrease in the average weight of eggs laid by the different hens in 1916 as compared with 1915. TABLE XVIII. COMPARISON OF THE AVERAGE WEIGHT OE EGGS LAID BY EACH HEN FOR TWO YEARS Hen Increase 1916 Decrease 1916 Breed &rams grams South African 1410 127.15 South African 2071 5.80 South African 2105 70.30 South African 2136 60.70 . • . > South African Average 63.09 . . . • ,*Jubian No No. 2170 112.00 Nubian 96.00 Nubian Average 2305 8.66 56.70 Cross-bred • * • • Cross-bred 2180 11.90 Cross-bred 2292 39.46 > ■ ■ ■ Cross-bred Average 28.07 Average of flock ' 42.52 The above table indicates that there were slight variations between the average weight of eggs laid by the different hens over the two years, but there is a remarkable similarity between the two years. The average of the entire flock was 42.52 grams heavier in 1916 than in 1915. This is a very small increase for it is less than two ounces dif- ference between eggs that weigh approximately 3^2 pounds. In othn* words the average weight of all the eggs laid in 1916 was 2.8 percent heavier than that of the previous year. As some of these birds were immature, it is thought that the increase in the average size of the egg was due to natural development rather than to the feed they consumed. Again, hen No. 1410 laid the smallest average weight of eggs and No. 2292, the heaviest. The same relative position was occupied also by the hens that laid the second, third, and fourth heaviest average weight of eggs each year. Hen No No. laid eggs that were large the early part of 1915, but she received an injury about the middle of 292 TWENTY-SEVKNTH AnNUAIv REPORT the laying season, after which the eggs laid by her were much smaller. In 1916 the eggs from this hen were more comparable in size and ap- pearance with those that were laid the year before the injury. This partly accounts for the greater increase in the average weight of eggs laid by this hen in 1916 over that laid by any other hen. Table XIX gives the ranking of the birds according to the average weight of eggs laid by each hen during the two years. TABLE XIX. HENS ARRANGED ACCORDING TO AVERAGE VV^ElGHT OF EGGS FOR TWO YEARS Ranking 1915 Hen Average weight of egg, 1915 Ranking 1916 Hen Averp.ge weight of egg, 1916 grams grams 1 2 3 4 5 6 7 8 9 1410 No No. 2305 2071 2105 2136 2180 2170 2292 1279.6 1473.0 1485.7 1489.3 1496.5 1510.7 1612.7 1 704.9 1761.6 1 2 3 4 5 6 7 8 9 1410 2071 2305 2105 2136 No No. 2180 2170 2292 1406.75 1483.5 1542.4 1566.8 1571.4 1585.0 1600.8 1608.9 1801.0 Tlic iccight of eggs laid by each hen, igi6: There was a great range in the total weight of ggs laid by each hen. Thus hen No No. gave 25,360 grams of eggs, while hen 2292 laid 61,234 grams. This is a difference of 142 percent between the eggs laid by the hen that gave the lightest weight of eggs and the one that laid the greatest weight. Between these extremes the hens range close to the average, which was 46,330.3 grams or 102.3 pounds. Table XX ranks the different hens according to the total weight of eggs laid. TABLE XX. HENS ARRANGED ACCORDING TO TOTAL WEIGHT OF EGGS, 1916 Ranking Hen Total weight of eggs, 1916 grams 1 No No. 25360 2 2071 37088 3 2136 40858 4 1410 42202 5 2305 47816 6 2180 52827 7 2105 53274 8 2170 56313 9 2292 61234 Average of flock 46330.3 (102.3 pounds) Effect of breed: Again, it was noted that the South African eggs are distinctly smaller than the Nubian or cross-bred eggs. They are more deeply pitted on the surface and have not the gloss shown in the Nubian or cross-bred eggs. With the exception of one bird, 2305, Arizona Agricultural Experimijnt Station 293 vvhicli laid an egg that was lighter than the other cross-breds, there is a striking uniformity in the weight of the eggs laid by the birds of dif- ferent breeding. Thus the South African hens averaged 1507.11 grams, while the Nubian averaged 1596.95 grams, and the cross-bred 1648.0 grams. There was not one of the South African hens in 1916 that laid eggs as large as any of the Nubians or cross-breds with the exception of 2305, as previously mentioned. The South African yielded eggs that averaged 89.85 grams less than the Nubian and 140.89 grams less than the cross-breds. These figures are similar in many respects to those secured the previous year. INSTRUCTION AND EXECUTIVE WORK Along with investigations summarized above time was given to teaching students and conferring with practical farmers who came for personal advice. The correspondence has been unusually heavy and considerable executive work has been required in the department. A reinforced concrete silo has been installed at the University Farm, and also a silo filling outfit. Other facilities for taking care of the livestock at the farm have been secured. There has been little change in the number and kind of animals maintained on the University Farm. During the past year 11 cows completed lactation period averaging for the herd 55 days dry before calving, 332 days in milk, and yields of 8231 pounds of milk, and 327 pounds of butter fat. The registered Hereford cows all dropped calves within the year, and most of these have been sold at ruling prices. During the year the University purchased four registered Hampshire ewes, and these are also retained for class room work, along with the Shropshire and Tunis breeds. Four breeds of chickens, namely : Single Comb White Leghorns, Single Comb Rhode Island Reds, White Plymouth Rocks, and Black Langshans are being maintained in the poultry plant. These are used chiefly for class room purposes. A special efifort is being made to develop uniform flocks and herds suitable for experimental purposes in the future. The livestock main- tained is entirely inadequate for these purposes, but it is hoped that the numbers may be increased, and the quality improved so that the animals will be especially suitable for investigation and class room purposes. R. H. Williams, Animal Husbandman. W. S. Cunningham, Assistant Animal Husbandman. / ENTOMOLOGY An extensive series of experiments in the control of the alfalfa seed chalcis fly was planned in the spring of 1915, and arrangements were made with eleven alfalfa seed growers near Buckeye and Chandler for testing out the trap border control method mentioned in the last report. The heavy rainfall in the late winter resulted in such variability in the growth of alfalfa that in several instances the growers abandoned their plans for producing a seed crop in the fields in which the tests were arranged for, and in other cases the growers failed to follow the plan agreed upon owing to a misunderstanding of their directions to workmen. In all other cases the period of eight or ten days allowed between the cutting of the borders and the main part of the field re- sulted in too slight differences in the setting of seed pods. The outcome was disappointing in view of the time and efforts made to arrange for the cooperative experiments on a large scale. It is believed that in further work along this line fourteen to fifteen days should be allowed for the differences between the trap borders and strips and the main part of the field. Continuous oversight of such experiments, which it has not been possible to give so far, will be necessary before they can be conducted satisfactorily. Work against the harvester ants in the ten-acre field near Phoenix has continued. Conditions in the field were more unfavorable than would occur in the average field. Owing to lack of care during 1915 a heavy crop of foxtail grew in the field in the spring of 1916. This was cut, and on May 12, when the season's work against the ants began, it was lying on the field so as to make it difficult to find the nests. During the season a total of 74 nests were found and treated, including many weak colonies which appeared to consist of only a few individuals in each case. The nature of the nests is indicated by the fact that an average of only 1.3 ounces of London Purple were needed for each nest during the season, whereas two seasons ago in the same field the poison required for the 168 nests averaged 2.7 ounces each. The labor and expense for the treatment has been increased disproportionately to the possible injury from the ants owing to the splitting up of the larger nests. Eliminating labor which should be charged to the ex- perimental end of the work and putting all expenses on a basis of practical farm work the cost for the year 1916 averaged about 64 cents Arizona Agricultural Experiment Station 295 an acre as compared with 40 cents in 1915 and $1.19 in 1914. This experiment will be continued for two more seasons, making five in all. An outbreak of one of the false chinch bugs (Nysius minutus Uhl.;* in the spring of 1916 in the Salt River Valley called for some attention from the experimental standpoint. The most important crops attacked were Irish potatoes and flax. The principal source of the insects seems to have been the common pig v^eed, Chenopodium album. On weeds the insects may be destroyed by means of blast torches or strong sprays of kerosene emulsion. On vegetable crops nicotine sul- fate— whale oil soap solution was recommended. Experimental work with these insects was limited to attempts to control them on experi- mental plots of flax at the Experiment Station Farm near Phoenix. On May 15 the flax plants were literally swarming with the bugs, mostly in the adult stages. The seed was the special object of attack, the entire seed crop being seriously threatened. The flax was growing in rows and collecting the insects by mechanical means was obviously the most practical method of protecting the crop. A special galvanized iron collector was devised to be used with a film of kerosene on water in the collecting pan as in ordinary hopperdozers, and this proved satis- factory for work on small plots. For collecting these insects on large acreages of flax the same principle has been incorporated in plans drawn up for a simple device on wheels ^ which can be pushed at a walking pace along the row. Flax seed seems to be a promising crop for southern Arizona and these bugs will have to be contended with from time to time if this industry is developed. Their control by me- chanical means in flax fields appears to be an easy matter. The col- lecting device will be perfected and given a practical demonstration when the false chinch bugs appear again in injurious numbers. A. W. Morrill, Consulting Entomologist. *Determined by the late O. Heideniann of the U. S. Bureau of Entomology. Closely related if' not a subspecies of the common false chinch bug, Nysius ericae Schill (A\ angiistatus Uhl.) CHEMISTRY The chemical laboratories of the Agricultural Experiment Station have been moved during the year into their new and permanent quar- ters in the Agriculture Building. The allotment for the equipment of these laboratories has been used for the substantial and permanent installation of only the most essential furniture, rather than in attempt- ing to complete the laboratories. Sufficient equipment is now in place to continue the research and other activities of the laboratory. Further improvement, however, is needed to meet the increasing demands upon the department. The usual service has been rendered the public in the analysis of irrigating water and the examinations of soils for alkaU. A few soil analyses have been made in urgent cases. The research work of the department has been varied and several important projects are being developed. The study of alkali has continued and accurate maps have been drawn showing the stand of successive crops on a piece of black alkaline land at the University Farm. This tract has been divided into strips by the borders usual on irrigated land, and the various strips have received treatment per acre as follows : Land 30, 10 tons barnyard manure; Land 3\, 20 tons barnyard manure; Land 32, 20 tons barnyard manure and 10 tons gypsum; Land 33, 10 tons gypsum; Land 34, no treatment ; Land 35. 400 pounds acid phosphate and 20 tons barnyard manure ; Land 36, 500 pounds acid phosphate ; Land 37, 400 pounds quicklime ; and Land 38 (new border), 500 pounds nitrate of soda in three applications, only one of which was made. Parallel with the field operations laboratory investigations are being made. The alkali studies have now been organized as an Adams Fund project. The annual analysis of the Salton Sea water in cooperation with the Carnegie Desert Laboratory has been made. Following sug- gestions afforded by the study of the concentration of the Salton water. we have made partial investigations of certain possibilities regarding the mode of formation of caliche which seem to warrant further work. Monthly samples from the Tempe drainage ditch are being analyzed for the systematic study of the changes in the composition of the drain- age water from a typical drained reclamation area. It is desired to extend this investigation to the amelioration of alkali in the soil at a few selected localities in the district. The effect of non-essential elements, especially boron and iodine, in stimulating plant growth has been carried on in the department by a graduate student. ArizoxNa Agricultural Experiment Station 297 SALTON SEA water The tenth annual sample of the water of Salton Sea was taken June 10, 1916, over deep water off Salton. The results of the analysis are given in Table XXI. TABLE XXI. COMPOSITION OF SALTON SEA WATER, JUNE 10, 1916 Total solids (at 110°C.) Water of Delusion and liNdration. Sodium Potassium Calciiun Magnesium Aluminum Iron Carbonic, CO2 (total) Bicarbonic, HCO3 (volumetric) . . Silicic, SiOj Phosphoric, PO4 Boric acid Oxygen consumed Nitric Nitrous Parts per 100,000 1647.2 47.5 528.9 5.71 > 29.85 27.17 .034 .060 11.40 16.10 1.21 doubtful trace trace .170 none trace From June 8, 1915, till June 10, 1916, the total solids in the Salton water have increased from 1377.4 parts per 100,000 to 1647.2 parts per 100,000, which is equivalent to a concentration of 19.6 percent. This is the greatest annual concentration noted with one exception, the con- centration from June 8, 1909, till May 22, 1910, having been 21 percent. Aside from the concentration of the solids collectively, there is little requiring discussion at this place. Mention, however, should be made of phosphoric acid. In the early annual analyses of the series weigh- able amounts of yellow precipitate were obtained. For several years the phosphoric acid test remained positive by scratching the sides of the beaker with a stirring rod, but at this time no unmistakable reaction can be obtained from three liters of water. Phosphoric acid, therefore, has been reported as a doubtful trace. Early in this series of analyses of the Salton water it became evident that calcium and carbonic acid were being lost. How this loss took place was not evident. Algae and bacteria were known to deposit lime, and J. C. Jones showed the ancient deposits of travertime about the Salton Sea to have been formed in this way. Later the writer called attention to the fact that potassium, although present in the water in very small amounts, was following the same course as the calcium. Undoubtedly phosphoric acid and possibly nitrogen must be added to the same list. 298 TwENTY-SIiVKNTH ANNUAL REPORT This observation on the behavior of phosphoric acid has important bearing on the theory of soil fertihty. Probably aside from physical and chemical processes, plant foods are fixed from the soil water and conserved by lower organisms in deposits other than their own tem- porary remains. CALICHE Large areas of mesa soil in the Southwest are underlaid at various depths by deposits of lime-cemented soil, sand, and gravel commonly called caliche, but recently named desert limestone by geologists. While these areas, because of the caliche, are less valuable for agricultural purposes, the analyses published in the Twenty-fourth Annual Report of this Station, page 567, show caliche itself to be supplied with plant food as richly at least as the soils with which it occurs. Because of its dense, hard character caliche takes water badly and plant roots cannot penetrate it. Nevertheless, where covered with a fair amount of soil, these desert limestone areas may become important in the production of special crops such as cactus, agave, guayule, and desert olives. It has generally been held that caliche resulted from some form of evapora- tion. The usually accepted theories are given in detail in Guild's Mineralogy of Arizona, page 48. Reasoning from observations made in connection with the study of the Salton Sea the writer was led to suspect the organic origin of these limestone deposits. Consequently, field and laboratory studies have been begun. In the field the lower courses of caliche are dense, while toward the top of the deposit calcareous caps with occasional interlying layers of uncemented soil are more frequent. Occasionally, however, caps are found beneath strata of dense caliche a foot or more in thickness. The strongest evi- dence of organic origin of caliche is found in these caps. The to- pography of the capped surface is very irregular and successive over- lying caps often approach within two or three inches at one place, while ten feet away they may be separated by a foot or eighteen inches of cemented gravel. The caps in passing over boulders take the curva- ture of the boulder, and even may be found overhanging. Instances occur of erosion of the massive caliche and a subsequent deposition of a cap over the nearly perpendicular eroded surface. It would be difficult to explain these features by evaporation or simple sedimentation. Gen- erally the caps occur on massive beds of cemented gravel, but frequently seams of gravelly loam an inch and even more in thickness may be found overlying one cap with a second thin cap overlying the loam. The lower face of the cap in contact with the loam is an exact cast of Arizona Agricultural Experiment Station 299 the top of the loam layer and non-adherent to it, but its upper surface is quite regular and smooth. Pebbles embedded in the cap are frequent, and the laminae formed after the pebbles became embedded take the contour of the pebbles. When a broken cap is examined in a proper light, it is seen to be laminated and the laminae show various shades of color, from nearly white to chocolate according to the foreign material that became trapped in the lime deposit as it was forming. Thus the caps could have been formed only at the surface and not by any sort of subsurface evaporation. Caliche-like incrustations of con- siderable thickness occur over basalt rocks on the slopes of buttes adja- cent to Tucson. Fossils are absent in cahche with the exception of diatoms, which the writer has found only in one specimen. From its mode of occurrence caliche appears to have been formed by lime- secreting organisms either in water or on surfaces that were frequently wetted with limy waters. During intervals of comparative quiet when little debris was being introduced and there was little interruption to the growth of these organisms the smooth caps may have been laid down. A few observations that may be corroborated by anyone during the ummer months render this theory more plausible. Leaky hydrants supplied with the hard Tucson city water rapidly become covered with lime-secreting algae and deposits of appreciable thickness are formed. These deposits cannot be due to evaporation. On the con- trary flowing hydrants on the University grounds, supplied with a less hard, slightly black alkaline water, form only light lime deposits. On hot summer days with intense insolation caliche roads under lawn sprinklers become green with algae (probably lime-secreting species) in two or three hours. If these processes were continuous and extraneous matter introduced, undoubtedly caliche-like deposits would be formed. The chemical evidence of the organic formation of caliche has been less completely worked out. It appears, howeyer, that the per- centage of readily soluble potassium and the potassium-sodium ratio is quite high in caliche. A few comparative determinations of phos- phoric acid on caliche and on the interlying and overlying loams show the phosphorous content of caliche much higher than that of the associated soils. If caliche were merely lime-cemented soil we would expect the opposite relation to exist, phosphates being moved but slowly by ground waters. Further analytical work will probably corroborate these observations, and show the similarity of caliche to travertines of known organic origin. 300 Twenty-seventh Annual Report plant stimulation with non-essential elements The results obtained by Japanese and French investigators in the stimulation of plant growth by various non-essential elements were reviewed by Mr. P. W. Moore, a graduate student and fellow in the department. The original articles were all carefully studied and a critique in manuscript form made available. Experimental work was confined to boric acid and potassium iodide. Unquestionable stimula- tion, especially of the root system, in both water and soil cultures was obtained, and stimulation with boric acid appeared to give considerable promise of practical use in the culture of root crops, especially radishes. Mr. Moore's own conclusions are as follows : "Both boric acid and potassium iodide are of undoubted value, at least in the culture of radishes. The optimum concentration for both appeared to be in the neighborhood of 750 grams (about 1% pounds) per acre. For potassium iodide this is about ten times the dose recommended by the Japanese investigators. It corresponds fairly well with the dose of boric acid recommended by Agulhon for radishes. The bottoms are increased more than the tops. There seems to be no advantage in using both stimulants at once. If boron and iodine each perform some special function in the plant, then both of them together should be more beneficial than either by itself. Accordingly it is difficult to explain in this way the effect of stimulants, at least in the case of boron and iodine." CHANGES IN CHEMICAL CHARACTER OF THE TEMPE DRAINAGE DITCH WATER The opening of a ditch draining the alkaline area south of Teinpe during the last summer offered unusual opportunity to study quanti- tatively the effect of draininge reclamation on the composition of the water and soil of the drained area. Consequently soon after water began to fiow in the new ditch monthly samples were collected and analyzed. The results of the analyses are shown in Table XXII. The very briny flow shown by the first analyses improved rapidly in composition as the ditch progressed and the flow increased. In September an unusually heavy rainfall raised the water table in the district and undoubtedly increased the flow, although there was no previous flow with which to compare, since the ditch is under constritc- tion and new areas are being added daily. The character of the drain- age water has improved each month until in December the dissolved salts (or alkali) amounted to less than one-fifth that in the original flow. This is due to the improved character of the drainage encountered at or near the head of the ditch rather than to actual sweetening of the drainage at any one point, although such sweetening is undoubtedly occurring. After the completion of the ditch, improvement in the quality of the flow will be attributable to draining off the stagnant alkaline water and its replacement with purer drainage water. The re- markable change in composition with the probability of further im- Arizona Agriculturai^ Experiment Station 301 provement promises well for the use of the drainage water for irrigat- ing lands on the Indian reservation below. It would be inadvisable, however, to apply the drainage water too soon on valuable lands, since rapid and marked improvement may reasonably be expectel. TABLE XXII. COMPOSITION OE WATER EROM TEMPE DRAINAGE DITCH, PARTS PER 100,000 (by C. N. catein) Date, 1916 Total solids Chlories as NaCl Hardness (perma- nent) CaSO, Hardness (tempo- rary) Ca(HCO.,).. Alka- linity NaoCOa SO. CaO MgO June 25 July 13 Sept. 10 Oct. 10 Dec. 8 Nov. 10 1665.2 1359.0 599.4 418.0 312.6 346.4 1170.0 993;51 432.0 303.0 228.0 220.0 107.44 27.2 13.0 5.4 7.6 67.2 66.4 64.0 60.3 172.58 64.76 30.49 33.78 97.64 14.2 14.6 12.6 65.2 25.2 15.75 17.57 MISCELLANEOUS The assertion has often been made that sorghum grown in arid regions produced syrup of poor quality due to excessive mineral salts. Recently a sample of sorghum syrup of apparently good quality pre- pared from cane grown near Yuma was examined in this laboratory. In the accompanying table a comparison is made of the Yuma product with analyses reported in Wolff's Aschcnanalysen and Wiley's Foods and Their Adulteration. The Arizona syrup contains less than half as much mineral matter as Wiley's example, although it appears to be about the same concentration. It contains only a little more mineral matter than the average for raw sorghum sugar according to Wolff, and very much less than the molasses from raw sugar. We presume the samples reported by Wolff and by Wiley were produced in humid climates. One striking feature of the ash of the Arizona syrup com- pared with Wolff's sample is its relatively high sulphate content and relatively low chloride content as shown in Table XXIII. TABLE XXIII. ASH CONSTITUENTS OF SORGHUM SYRUP AND SUGAR Solids Ash SO4 in ash CI in ash. . . Wolff's Aschenanalysen Wiley's Foods Raw sugar Molasses from raw sugar percent percent 1.67 8.84 5.85 5.10 4.30 5.74 Sorghum syrup percent 76.0 4.0 Ariz. Station Sorghum syrup percent 74.0 1.83 15.26 3.31 An interesting instance of water of opposite character and nicely adjusted supply from the same well comes to us from near Toltec in the Casa Grande Valley. The owner has installed a small pump with 302 Tvve;nty-se:venth Annual Report shallow suction to fill an elevated tank for domestic use. The surface flow, which is agreeably black alkaline and soft, accumulates in the top of the well when the larger, deeper-set irrigating pump is at rest, but its volume is not sufhcient to afifect in any marked way the more abundant flow of most excellent hard irrigating water met at greater depths. The composition of the two waters is given in Table XXIV. table; xxiv. COMPOSITION OF DIFFERENT WATERS FROM THE SAME well; PARTS PER 100,000 Upper scanty flow domestic water Lower abundant flow irrigating water Solids at 110° C Chlorides as NaCl.... Permanent hardness as CaS04 Temporary hardness as Ca(HCa)2 Black alkali as Na.CO^ 39.0 3.0 4.3 23.5 A. E \^INS0N, Biochemist. C. N. Catlin, Asst. Chemist. IRRIGATION INVESTIGATIONS CASA Grande; valIvEy The groundwater investigations outlined in the last Annual Report have been prosecuted. A mass of data on the groundwater table has been accumulated, but since movements of groundwater may be very slow, it is possible even now to draw only tentative conclusions. The gauging stations at Tucson have been maintained, and new stations established on the bridges and culverts on the Arizona Southern Rail- way between Red Rock and Sasco, and on the Southern Pacific Railway between Picacho and Maricopa. The floods of the year were very fortu- nate from an investigator's standpoint, inasmuch as they were unusually large, yet not destruci've to the bridges on which the gauging stations depend. Special efforts were made to obtain the highest possible ac- curacy in the measurements at Sasco in order to obtain the true dis- charge at that point, where the Santa Cruz debouches into the Casa Grande Valley. Condensed records of the stream flows are given in Table XXV. TABLE XXV. RUN-OFF RECORDS FOR SANTA CRUZ AND RILLITO RIVFRS IN 1915 AND 1916 1915 1916 N 3 C U o dp u a G o§ <~ o ug 2 Eh a > Dowest Date 17° Dec. 5 15° Jan. 6 16° Jan. 4 18° Dec. 6 6° Jan. 7 22° Dec. 15 19° Dec. 28 15° Dec. 11 Last killing- frost in spring Apr. 7 Mar. 27 Feb. 20 Mar. 12 Mar. 27 Feb. 28 Mar. 7 Mar. 25 1) First killing frost in autumn Nov. 10 Dec. 21 Nov. 12 Oct. 29 Dec. 5 Dec. 7 Nov. 11 Nov. 8 00 Total pre- cipitation 10.21 9.80 11.25 9.84 9.32 19.9 12.62 13.15 Highest Date 106° F. July 13 104° May 29 102° Aug. 18 114° May 30 108° July 5 102° June 21 102° 1 June 22 102° July 4 It Lowest Date . * 5^ Jan. 6 Dec. 25 * 0° Jan. 7 20° Jan. 21 14° Dec. 28 6° Dec. 11 i^ast killing frost in sprmg * Apr. 17 * * * May 2 Mar. 22 Apr. 15 o ii'irst killing frost in autumn Oct. 7 Nov. 30 Oct. 22 Oct. 22 Oct. 27 Nov. 27 Nov. 11 Nov. 8 Total pro- ci))iiaiion * 12.90 * * 9.03 18.01 13.49 14.69 ■'Not given, ffiescott data 1909 to 1912 inc. The terms "killing frost" and '"freezing temperature" as far as dam- age to vegetation is concerned, are not strictly interchangeable. How- ever, in an arid section, a killing frost seldom occurs until the tempera- ture of the air has fallen somewhat below freezing point ; and, moreover, the range in daily temperature being relatively great, the duration of freezing temperatures is shorter. Thus frost temperatures may often be experienced with little harm to vegetation. The growing sea.son in the northern part of the State at the higher altitudes is very short, and hard freezes arc common late in spring and early autumn. Destructive 314 Twe;nty-se;ve;nth Annual Re;port frosts in central and southern Arizona are very uncommon, and when they do occur it is during December and January. Referring to Weather Bureau reports for aU points within the State, the mean annual temperatures for 1911, 1912, and 1913 were the lowest for many years. The minimum temperatures for 1911 and 1912 were not unusual, but the January freeze of 1913 was the most severe within the history of the State. ■ On January 6, 7, and 8 the lowest temperatures ever known were recorded in nearly all sections. The maximum temperature is usually reached during June or July. May, 1910, was abnormally warm, breaking all previous records for May, and the temperatures of May 29 or 30 are, in most instances, the maximum temperatures reached during a period of many years. How- ever, considering the high day-time temperatures of Arizona from a human standpoint, it must be remembered that the thermometer is not a reliable indicator of physical comfort. Heat is rapidly dissipated from the body by reason of excessive evaporation due to the extreme dryness of the atmosphere. This dryness, with almost constant breezes, renders the temperatures, that in more humid sections would be intolerable, easily endurable. The daily range in temperature is great, being from 30 to 60 degrees, and the resulting cooler nights during the hot season are most enjoyable. There are two rainy seasons, the more distinct one beginning each year early in July and ending about the middle of September. The rains during this season are usually local and of short duration, but torrential in character. The other rainy season is not so well defined, and pre- cipitation may occur in the early winter, or as is more usually the case, in February and March. Much of the precipitation at higher altitudes in the winter months is in the form of snow. So much depends on the timeliness of the rainfall that the total precipitation for the year is not a certain indication of its effectiveness. Although the av^erage rainfall for the State for 1913 was but slightly below the normal, the year was exceptionally unfavorable for all interests dependent upon adequate and timely precipitation. Bulletins 64, 65, and 70 of the Arizona Agricul- tural Experiment Station contain excellent discussions of the character and extent of the rainfall of Arizona with its bearino- on irrieation, grazing and agriculture. Tables XXIX and XXX show some monthly and annual data for the year 1916. The temperatures for the year for the State as a whole may be considered as about normal. A frost March 25 and 26 badly damaged Arizona Agricultural ExpI'Rimlnt Station 315 o w K Q o o S S o < w W CU o ti <:« D Pi W Pi •z l-H I— I < o o a

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CO \q ^ * irJO'^ONO'rO^i^'rig^ .— .CMCNjrO^'-OirjTj-cO'— I * OC^<^l'^"^"^C7NS"^QrA r^ooootxJONONOOONt^coNo vo o:i c^i c-i -^ o~- c^i t^ 't o~- '+ ^ -:^ ^ O '^ 0-' cr' -*■ CD "^ ^2 3; i/^ ■uiW •XBJV[ UT39H ir>cci'-^t^ONCN)C>000'— i^Ci Cvj ^ ,— . r-H ro CO ro ro CNl >— ' l: lO CSOODON-d-NO^l'^Ot^ONCOO o oo ooooooo CO* r^ro* CMOOOOOOCMQC in NO rrj i< 00 CD 00 CD CTn t>^ !->. t^ t^ u-> in CO ■uiW r^^^,--,Ln* 0"^<^ONfMCO\0 f » CVl ro CO -^ -^ m CO CO • Si >. !:/". Q, 4J > cJ NO 1^ o O 3 > To -^ o 25 316 Twenty-seventh Annual Report TABLE XXX. MONTHLY AND TOTAL PRECH'ITATION IN INCHES FOR 1916 V-i S 4) >> S o3 s O .., 0 s-g 3 (-. 0) o UCS tate niv o t- 5 b IXQ \mO 0^ tHXP OQ January. . 2.70 8.16 4.33 .64 2.34 4.00 2.20 February .64 .77 .31 .01 .13 .58 .48 March . . . .83 1.77 1.45 .25 .37 .50 .63 April .... .18 .06 .41 T .15 .51 .08 May 1.52 .37 .05 0 T 0 .28 June 0 0 0 0 0 .07 0 July 1.27 2.46 2.22 .67 .77 2.03 3.7S August. . . 1.57 3.29 2.66 0 .30 2.26 4.10 September .72 1.78 1.13 T 1.66 1.29 1.55 October. . .71 3.61 2.65 0 .65 1.10 1.36 November 0 0 0 0 0 0 0 December 1.30 1.11 .03 .73 .39 .81 .23 Total for year. . . . 11.44 23.38 16.14 2.30 6.76 13.15 14.69 Normal . . 11. 16 22.73 * :k 7.90 11.93 11.78 *Not given. fruit in the central and eastern cotmties. Ang'iist and September were slightly cooler than nstial. September had more than its normal ])re- cipitation, and excessive rains in the u]danfls north of Salt River Valley caused floods which broke the main canal and flooded a portion of the }>roject, causing considerable loss to farmers as well as damage to the canal system. November, as compared with other years, broke all records for low temperature, dryness and abundance of sunshine. Although tiiere were no unusual extremes of cold, the temperature of December was ahiKjst continuously below normal, and the precipitation was less than usual. The total precipitation was slightly below that of the previous year. January, 1916, however, is the wettest month on record for many years. The melting of the December snows and the heavy rains caused floods throughout the State. According to reliable information, the high- \\ater marks of the Salt and Gila Rivers this season have not been exceeded since 1891. May. usually the driest month, had less tlian average rainfall this year, but June was still drier, the only ai)prcciablc precipitation being at Tucson. Farms without irrigation suffered. As a whole, the weather conditions of 1916 may be considered as favorable to the agricultural and grazing interests of the state. C. N. Catlin, Observer, EDUCATIONAL AGRICULTURAL INSTRUCTION IN THE UNIVERSITY The healthy growth of the College of Agriculture is indicated by tlie graduation of eight students in June. 1916, with the degree Bachelor of Science in Agriculture, and one Bachelor of Science doing major work in agriculttu-c. The present senior class numbers eight, most of vdiom will probably be graduated in June, 1917. The enrollment in the College of Agriculture since its organization in 1908 is as follows : students < 1908-1909 2-year course and others 9 1909-1910 2-year course and others 15 1910-1911 2-vear course and others 26 1011-1912 2 and 4-ycar courses and others 38 Total 9 and 4-vr Other receiving courses and ^^^^t^^^ instruction suecials elect ng- m agri- speciais agriculture culture 1912-1913 26 27 53 1913-1914 29 9 38 1914-1915 41 7* 48 lQlS-1916 59** 3* • 62 1916-1917 (1st semester onlv) . . 51** 1 52 ♦Including one student in the College of Arts and Sciences majoring in agriculture. **Including two graduate students. During the first years that instruction in agriculture was given the organization was that of a department rather than a college. Conse- quently all students taking agriculture were enrolled in the Agricultural course. These included preparatory students and students in the general Arts and Science courses. The number of these has diminished from year to year due to the withdrawal of preparatory work and to changes in the curriculum of the College of Arts and Sciences by which applied sciences, including agriculture, were segregated and no longer accepted as meeting the requirement in pure science. These losses in numbers have been equalized by new enrollments in the College of Agriculture. The organization of the College of Agriculture Ins been strength- ened materially by cataloging the work of the college, formerly all classified as agriculture, in five distinct deiiartments. Agricultural Chemistry, Agronomy, Animal Husbandry, Horticulture, and Plant Breeding. By the fortunate combination of the Agricultural College 318 Twenty-seventh Annual Report with the Experiment Station the services of men engaged in research under our pecuHar conditions can he secm-ed as major professors. Like- wise opportunity is afforded the student in many instances to famiUarize himself with investisrations being carried out bv the members of the Experiment Station Staff. The curriculum has also been strengthened by adding new courses. Through the cooperation of the Department of Zoology in the College of Arts and Sciences a course in Entomology is being given for the first time. This enables the College of Agricul- ture to train men for horticultural inspection work as well as to round out the general instruction given in horticulture and agronomy. Further cooperation with the other colleges of the University is contemplated. The Agricultural student body has shown excellent spirit during the year. They have entered heartily into the affairs of the general student body and have contributed much to social and athletic life on the campus. The Agricultural Club has held regular meetings with interesting and instructive programs carried out for t-lie most part by the students. The Staff of the Experiment Station has also held a monthly Agricultural Science Seminar which, while not primarly for the student body, has been open to them and some have improved the opportunity to attend and take part in the discussions. AGRICULTURAL INSTRUCTION IN THE STATE In accordance with Paragraphs 2791-2797, Laws of 1913. granting state aid to high schools and normals for instruction in agriculture and industrial arts, twenty-one schools have qualified. Of these nine are offering courses in agriculture ranging from a single year's work in general agriculture to more or less specialized four-year courses. The other twelve institutions receiving state aid are devoting it to industrial courses, including home economics but exclusive of agriculture. While the statistics at our disposal are too incomplete for publication we feel that the teaching of agriculture in secondary schools deserves more at- tention than is being given. One or two elective units of the high school curriculum can be given to such instruction, even in the mining districts, with advantage to the individual and to the State, especially to pupils who do not contemplate taking a college course in agriculture. Those contemplating a college course, however, should be advised to take the regular college preparatory course with just enough agriculture as free elective to arouse and hold their interest in the subject. Arizona Agricultural Experiment Station 319 FARMER'S SHORT COURSE The fourteenth annual Farmer's Short Course was held for two weeks in January, 1916, with a total enrollment of 163, including 35 women in home economics. This was the first short course organized with sections for different interests meeting simultaneously. With the increasing attendance this division becomes more and more practicable, and the farmers in attendance can be given a wider range of instruction from which to select what suits best their own needs. At the fifth annual Farmer's Short Course, lasting for one week only in January, 1917, three sections were given for farmers and one for the women in home economics. The attendance in 1917 reached 250 with 144 women in home economics. The growing attendance at the short courses justifies the invitation of specialists from beyond our own borders to come and give our farmers the newest and best each year in carefully chosen fields. The information and enthusiasm carried home by those attending are having a marked intiuence in bettering agricultural conditions in the State. The growth of these courses during five years has been : Registered Attendance 1913 80 1914 103 1915 143 1915 163 including 35 in Home Economics 1917 250 including 144 in Home Economics R. H. FoRUES, Dean. A. E. Vinson, Professor Agr. Cheni. 320 Twe;nty-se;ve;nth Annual Report o CO o ON On 14 O rjl W I — I Q o o IS o _2 ■ !=! in a. . "^.f'"' .^^ 0 n\ F Fig. 2. — Plan of rabbit drive. Flan of drive The pen, A, should be of sufficient size (usually about 20' x 20') to hold the rabbits of an ordinary drive. It should be made of stout close- mesh woven wire fence, 5 ft. high, WMth the bottom wire 3 to 4 inches under ground to prevent the rabbits from digging out. The wings, B and C, must also be of sufficiently close-meshed wire so that the smaller 322 Bulletin 81 rabbits will not get through. The fencing need not be as high as that for the pen, wire 24 inches high, or more, bHng suitable. The wings should be as long as they can be made. One mile is not too long, but a shorter length should catch many rabbits. These wings bad to a small opening, D, in the pen. The people in the drive form a semi-circle in front of the pen and wings, as shown by the small circh, E. The distance apart of the drivers and the distance from the pen depends upon the country, whether brushy or open grass land. In brushy country the drive should hi short, perhaps one mile ; while in open grass land the drives may extend over two to five miles. Th; people should carry tin pans, or other objects with which to make a noise and frighten the rabbits along, especially when beginning the drive and while the drivers are far apart. The drivers should walk at about the same gait, towards the pen, as shown by the arrow points. Other drivers may be formed in two flanks, one on each side. These will drive towards the front of the pen and form the lines C G, B G before the line E approaches them. No guns should be alloncd, for these may cause accidents; but each driver should carry a light club with which to kill the rabbits as they try to run through the line when it closes in near the p?n. The clubs are also to be used for killing the rabbits in the pen. In some localities there are farmers who have fenced large fi:lds with rabbit-proof wire fencing. In such places, these wir^ fences may be used to great advantage for rabbit drives, by using the wire fence for one of the wings of the drive, as shown in the following diagram : Fig. 3. — Fencing used for nibbit drive. The drivers should be placed in a semi-circle, the flank on the side B driving rabbits towards the front where they will th:n be driven towards A and into the- pen. It sometimes happens that there is a farm on each side of the road fenced, with the corners coming near each other on oppo- site sides of the road in such a way as to form the two wings, in which case the pen can be put in the road as shown. The writer remembers such an instance, near Cochise. How TO Combat Rabbits, etc. 323 In case there is no rabbit-proof wire fence to be used as above de- scribed, woven wire may be attached to ordinary pasture or field fence posts. If there is any farmer in the community who is buying woven wire to fence a field he should be induced to first loan his wire fencing to the community for use in a rabbit drive. Sometimes hardware dealers will rent fence wire to the farmers for this purpose, the farmers each contributing to the cost of the loan while the merchant deducts the rental from the sale-price of tiie wire on account of unrolling. Usage for this purpose does not ordinarily damage the wire. Where a large number of people engage in a drive many rabbits may be killed without the use of wire. The people form a large circle and gradually close in. In this way the rabbits are huddled together in the center where they become confused and can be clubbed easily. No guns should be nlloived. TRAPPING An effective trap can be made by using a pen similar to the one men- tioned for the drive, but smaller ( 10 x 14 ft.) and with a "goose-neck" entrance, as shown in the following figure: Fig. 4. — Pen trap with gooseneck entrance. The opening at A should be about 3 ft. wide and the end of the en- trance alley B should be narrowed down to 8 inches. The rabbits enter this trap and are unable to find their way out, unless they be left in the pen for several days. These traps may be made along garden fences, in which case C orD may be the corner of the fence. Attractive bait such as alfalfa, corn, sweet potatoes, etc., should be placed in the runway and inside the pen. This form of trap is more effective for jackrabbits, but will also often catch cottontails. For cottontails the following is a very effective trap: Nail 4 pieces of 1 X 12 inch boards, 2 ft. long, together to form a box without end pieces. A goods box may be used for this. Set the box in the ground directly under the woven wire fence, so that the bottom wire of the fence is 4 or 5 inches above the top of the box. Have a trap door on the top of the box as illustrated (Fig 5). The rest of the fence should have the 324 Bulletin 81 bottom wire well underground so that the rabbits will not dig under it. The rabbits will run along th? fence, looking for an opening. They will attempt to pass under the fence over the box, when the trap door will drop and let them into the box. T'a ^ p Daufi- ■3£CTiorr A. sSEiCTJort 3 Fig. 5. — Pitfall trap to be placed under fence. This form of trap has been found very effective. One farmer stated that he found from 4 to 6 cottontails in each trap for each of several mornings, until the number of cottontails was materially reduced. In firm soil, instead of putting a box in the ground a pit is dug, and a trap door, with supporting frame, can be used with equal effectiveness. Another rabbit trap, for cottontails, is made of two 1 in. x 6 in. boards, A and B, 3 ft. long and with two short cross pieces, C and D, at each end. Two piesces 1 in. x 5^1 in., about 2 ft. 3 in. long (£ and F) are nailed or fastened with screws atG, one end of the trap is placed beneath the woven -J'-O" • ,< 'A Lb vb I^T 30X ojs. J^rT \ J Fig. 6. — Another form of pitfall trap, for hard ground. wire at a point where the rabbits have been entering, the trap being inside of the garden or field. Undr the trap is a pit or box in the ground. When the rabbit gets near the center of the board, E or F , the board tilts and lets it fall int'O the pit or box. This kind of trap is being used in the San Simon Valley How TO Combat Rabbits, etc. 325 with great success. Many rabbits are being trapped in one of these in a single night. A door in the side of the pit or box can be arranged, through which the rabbits can be removed. During late fall and in winter cottontails make excellent human food, and the young ones are good to eat at all times of the year. Young jackrabbits are also good to eat during fall. and winter, if they are soaked overnight in salt water to which a little baking soda has been added. This will remove the "wild" odor and taste. Rabbits of all kinds make excellent food for poultry. Even poisoned rabbits may be used for this purpose without danger of poisoning fowls, or other animals, provided the head, stomach and intestines are removed and buried. Strychnine acts upon the nerves and kills the animals before it is absorbed into the circulatory system. One jackrabbit per day fed along with a grain ration is sufficient for 35 to 40 hens. The rabbits may be ground or chopped finely, or if fed fresh, may be cleaned and then nailed to a post for hens to pick at. poisoning Both jackrabbits and cottontails can be controlled and largely extermi- nated by systematic poisoning. However, care should be exercised in using poisons. The U. S. Department of Agriculture, Bureau of Biologi- cal Survey, recommends as follows: "When the law permits, poison can often be used to advantage, es- pecially at times when the natural food of the rabbit is scarce. The fol- lowing formulas have been employed with considerable success: "Alfalfa poison: Dissolve 1 ounce of strychnine sulphate in 2 gallons of boiling water and sprinkle over 16 pounds of leafy alfalfa hay, chopped in 2-inch lengths. The poisoned hay may be scattered in small heaps along rabbit trails in inclosures from which stock is excluded. "Grain poison: Mix together 1 ounce of powdered strychnine (alkaloid) and 1 ounce of baking soda. Sift this into 1 pint of thin hot starch paste and stir thoroughly. (The starch paste is made by mixing 1 heaping table- spoonful of gloss starch in a little cold water, which is then added to one pint of hot water and boiled until a clear thin paste is formed. Add one- tenth ounce of saccharine and stir. "Apply to 12 quarts of oats, rolled barley, milo maize or feterita. Mix well until grain is evenly coated. Use as directed for alfalfa poison. H the powdered strychnine alkaloid is not available, strychnine sulphate crystals may be used if prepared as for prairie dogs. "This same creamy paste can also be applied to orchard prunings. The smaller twigs should be cut up into 2 or 3 inch lengths and the poison applied in the same way as with oats. "Poisoned green baits: Cut up a supply of sweet potatoes, carrots, par- snips, apples, or other similar baits into cubes lA to 1 inch in diameter. Insert in each a small quantity of powdered strychnine or a small strych- nine crystal. When a larger quantity is to be prepared, the powdered 326 Bulletin 81 strychnine can be dusted over the bait by means of a salt shaker in the proportion of Ys ounce of strychnine to 2 quarts of the baits. "The poisoned grain, prunings, or green baits are dropped along rabbit trails or in places frequented by the rabbits, care bemg exercised in plac- ing them to prevent any possible injury to live stock." Rabbits are especially fond of sweet potatoes and these are the3-efore better than alfalfa for poisoned- bait. Several years ago the writer killed laige numbers of rabbits, mainly jackrabbits, on the plains of Texas, where the rabbits were numerous, by mixing a little powdered strychnine with salt, dampening this so the wind would not blow it away, and placing it in rabbit trails and along woven wire fences, out of reach of stock. In portions of the Southwest where there are alkali spots or "salt licks" to which the rabbits resort, this salt bait may not be effective; but where they cannot obtain salt readily the poisoned mixture would be efifective. The following salt bait has betn used successfully in Oregon: 2 quarts salt 1 quart sugar 1 oz. powdered strychnine One tenth of an ounce of saccharine may be substituted for the one quart of sugar and would be much better. Put this mixture out in small heaps of 1 to 2 tablespoonfuls each on hard ground where stock will not get to it. Still another poisoned bait for rabbits consists of 1 lb. powdered arsenic 1 gal. bran 1 qt. molasses Mix thoroughly and spread small quantities in rabbit runways as the sun is going down. PROTECTION AGAINST RABBITS The surest method of securing against damage by rabbits is to fence against them. For this purpose a woven wire fence at least 30 inches high should be used. It is more economical to put in a fence of good, stout wire than one of small and weak wire, like common poultry netting, which cannot usually be stretched taut. The mesh should be small enough to prevent cottontails and young jackrabbits from getting; through. One to one and one half inch mesh should extend to 16 inches above ground, and then the openings may gradually increase. Cottontails have the bad habit of digging under fences. To insure against this the bottom strand should be stretched taut upon the surface of hard ground, or 3 to + How TO Combat Rabbits, etc. 327 inches ben-ath the surface of soft ground. All washes or other openings beneath the fence should be securely closed and the field should be in- spected occasionally to see that no fresh openings have been made. If such are found they may be closed immediately or a trap set in the open- ing. One or two rabbits will usually do much damage to a garden or young orchard in a single night. Farmers who live in the same section of land can economize by co- operating in fencing their farms. Where there are four farmers in the same section, each having 160 acres, they can reduce their rabbit-fence expense by fencing the whole section on the outside, instead of fencing each farm separately. The expense of fencing can be reduced further if the people in the same locality will club together and purchase wire and posts in carload lots. Tree protection: Individual tree protectors of woven wire, wood, paper, straw, etc., are good to defend trees against cottontails, but these do not protect the lower branches from jackrabbits. The writer has seen many young fruit trees, the branches of which had been cut off above the protectors by jackrabbits. One farmer in the San Pedro Valley states that he paints his young fruit trees with nicotine oil and finds that the rabbits do not injure the trees; while the rabbits destroyed trees in a nearby orchard which were not protected. This, or any other oil or paint, should not be applied to the foliage, or to very young and tender twigs, as it may kill them. Young trees just set out may also be injured and even killed by a coating of grease or thick paint, as this coat will close the pores in the bark. These "paints" are not poisonous but are repellants. On>e tablespoonful of nicotine extract — "Black leaf 40", to ^^ gallon of whitewash is also effective as a repellant. The following formula is from one of the U. S. Department of Agri- culture Weekly Press Letters: Poisoned tree wash: "Dissolve 1 ounce of strychnine sulphate in 3 quarts of boiling water and add ^X pint of laundry starch, previously dis- solved in 1 pint of cold, water. Boil this mixture until it becomes a clear paste. Add 1 ounce of glycerin and stir thoroughly. When sufficiently cool, apply to trunks of tre-s with a paint brush. Rabbits that gnaw the bark will be killed before the tree is injured." Note: It is probable that >^ pint of molasses may be substituted for 1 oz. glycerin. This poisoned wash has proved highly satisfactory in the West and promises to be one of the most popular methods of protecting trees from rabbits. 328 Bulletin- 81 natural enemies Owls, large hawks and coyotes are animals that prey upon rabbitj; and other animal pests, such as prairie-dogs, gophers, rats and mice. Hawks (except the small "darters" or chicken hawks) and owls should be protected. They are very valuable in destroying harmful animals and they do practically no damage. Once the rabbits are materially reduced in number or nearly exterminated by drives, trapping and poisoning, thes? animals will usually ke?p them in such check that their damage will be negligible. GOPHERS The following formula for the control of gophers is recommended b\'- fhe U. S. Department of Agriculture Bureau of Biological Survey: DIRECTIONS FOR DESTROYING POCKET GOPHERS *Tocket gophers are readily caught in several makes of special traps commonly on the market, and a few of these suffice to keep small areas free of these pests. For ridding alfalfa fields, orchards, and long stretcher of ditch embankments of them, a very successful and much more practi- cal method is to poison them by placing baits of sweet potato or of pars- nips in their underground runways. "The baits should be cut about an inch long and a half inch square, and washed and drained. From a pepper box slowly sift % ounce of powdered strychnine (alkaloid) and 1-10 of this quantity of saccharine (ground together in a mortar or otherwise thoroughly mixed) over about four quarts of the dampened baits, stirring to distribute the poison evenly. "The runways, which are usually 4 to 8 inches beneath the surface, can be located by means of a probe made of any strong handle an inch in diameter and 36 inches long. One end should be bluntly pointed. Into the other should be fitted a piece of -)/« inch iron rod, protruding about 12 inches, and bluntly pointed. A foot rest aids in probing in hard soils. By forcing down this iron rod near gopher workings, or a foot or two back of fre^h mounds, the open tunnel can be felt as the point breaks into it. The blunt end of the instrument is now used to carefully enlarge the hole, a bait or two is dropped into the run and the probe hole closed. "One soon becomes expert in locating the runs, and a man can treat 300 to 500 gopher workings in a day. Baits need be placed only two places in each separate system of 10 or 30 mounds, which is usually the home of a single gopher. In our experience baits placed fairly in the op mi runs have invariably killed the gophers. The method has found great favor wherever it has been introduced." The writer has used poisoned bait made from sweet potatoes accord- ing to this formula and foundj it to be entirely satisfactory. He has also given demonstrations 'n making and using this poisoned bait and reports of satisfactory results have been received. Messrs. D. A. Gilchrist and Duane Stonier, assistants in the extermination of predatory animals, with the U. S. Biological Survey, rendered excellent assistance in this work during the fall of 1916 and winter of 1916-17. How TO Combat Rabbits, etc. 329 Fig:. 7. — Note the gopher holes ami small mounds around this dead apple trt'i'. (Joplicrf >\o much damage to crops as well as to orchards and gardens. They are especially inmMesom*- idjout reservoirs and irrigation canals and ditches. 330 Bulletin 81 PRAIRIE DOGS Prairie dogs are found scattered over large areas within the State, mainly in the northern and in the southern portions. They spread very rapidly. According to record the first prairie dogs found in the Sulphur ^^'^' Fiir. 8. — Which shall havt- the grass — the cattle, which are valuable, or the prairie dogs and har\ester ants, which are of no value? Prairie does and ants destroy grass, roots and tops, and also cause the soil to become washed away by flood waters. Use poisoned grain for the prairie dogs and London Purple for the ants. Spring Valley were discovered near Willcox about 40 years ago. Th^y are now infesting at least 200 sections of land in this valley, and ther? are many other sections which have been infested by thsse pests on which the "dogs" have destroyed the grass and have moved away. It does not talc? long for prairie dogs to destroy the grass on an area infested by them. They eat the crowns and roots of grasses, and they usually destroy the best pasture grasses first. They also prevent the reseed- ing of the grasses by cutting down the seed stalks, in their efforts to main- tain an open view of their towns. It has been estimated that 20 prairie dogs, with their normal increase, will eat or destroy as much grass in a year as a cow will consume. But this is not all the damage they do, for in destroy- ing the protective grass sod they leave the land bare for erosion, especially on slopes and hillsides. In such districts "washes" will occur which gradually increase in size, until grasses cannot again establish themselves. The writer has observed many such places. In other regions where the erosion is not so great, especially in sandy soil, when the prairie dogs are killed off and the cattle are kept off for one to two years, the good grasses reappear. Besides large areas of prairie dog-infested land in the Sulphur Spring Valley, there are many sections of infested grass land in the San Pedro How TO Combat Rabbits, etc. 331 Valley near Hereford, and westward toward »^he Huachuca Mountains; and in the upper part of the San Simon Valley. The grass on much of these 250 sections in the county has been destroyed, and is rapidly being destroyed on the balance of this area. Assuming 250 sections of land in Cochise County infested by these animals, a conservative estimate of the value of this area before the prairie dogs reduced it may be made from the number of cattle it would support. Twenty-five acres of average range in Sulphur Spring Valley will support one yearling for one year. Two hundred and fifty sections, 160,000 acres, will therefore support 6,400 yearlings which at a value of $25 each would be worth $160,000. This is a conservative estimate of the annual damage doen by these pssts in one county. The means by which to prevent this enormous loss is to exterminate the prairie dogs by poisoning them. This work should be planned, un- dertaken and carried out on a community, state-wide basis, although individuals can profitably keep them killed off their own land. The State Legislature (Session laws of Arizona, 1917, Chapter 48) has pro- vided that, upon petition of 100 residents of any county a tax of one- half mill may be assessed, and the resulting fund used to purchase and prepare poisons and distribute them to landholders for use against rodent pests. This law should be strengthened by compelling every land- owner to kill the "dogs" on his holdings. This should apply, also, to state and school lands. The National Government, through the Biologi- cal Survey, will co-operate by killing the "dogs" on Forest Reserves and the public domain, as it is now doing in the northern part of the State. Advisory assistance may also be rendered to communities and individuals. According to the U. S. Biological Survey there are seven species of prairie dogs. There are two distinct species in Arizona, — the small species in the northern part of the State and the large species, which is found in the Sulphur Spring Valley. According to Mr. D. A. Gilchrist of the U. S. Biological Survey, who has charge of predatory animal ex- termination work in Arizona, and who has had experience in poisoning these pests in both sections of the State, the small northern spxies hiber- nates during winter. This species, therefore, must be poisoned in spring and summer, when the grass is good, and hence it is more difficult to kill with poisoned bait than the southern species which is active the entire year and can be killed easily by putting out poisoned bait in winter, spring or late fall. However, in Cochise County, best results have been secured by poisoning during the dry months of March, April and May. Mr. Gilchrist and the writer tested milo, feterita, wheat and rolled barley for poisoned bait for prairie dogs in the Sulphur Spring Valley. 332 Bulletin 81 We found that rolled barley was most effective. Excellent results were obtained bj' making and applying bait according to the following formula, recommended by the U. S. Biological Survey: DIRECTIONS FOR POISONING PRAIRIE-DOGS IN ARIZONA "Dissolve 1 ounce of strychnine sulphate in 13<2 pints of boiling water. Add 1 heaping tablespoonful of gloss starch, previously mixed with a little cold water, and boil until a clear paste is formed. Add 1 ounce of baking soda and stir to a creamy mass. Add 1-12 ounce of saccharine and 34 pint of syrup and stir thoroughly. Pour over 13 quarts of rolled barley and mix vi^ell until every grain is evenly coated. Allow to dry before using. "In bushel quantities use, as above directed, 2j/2 ounces strychnine, 2^/2 ounces soda, 1-5 ounce saccharine, 1^4 ounces starch, 13^4 quarts boiling water and ^ of a pint of sirup. "Scatter poison, when the natural food of the prairie-dog is scarce, on clean, hard places near the holes, 1 quart to 50 holes. Do not put the poisoned bait in the holes. "If powdered strychnine alkaloid is used, prepare the hot starch paste first. Then sift strychnine and baking soda previously mixed thoroughly together, into the hot starch paste, and stir to a creamy mass. Proceed as in the above directions with sirup, saccharine, etc. "In some localities in Arizona where the natural prairie-dog foods are abundant, success with poison has not always been obtained by the usual methods. In such cases excellent results may be secured by placing a very small quantity of clean rolled barley at each active hole and after two days treat the areas with poisoned grain prepared as in the above directions. Caution "All poison containers and all utensils used in the preparation of poison should be kept plainly labeled and out of reach of children, irrespon- sible persons, and livestock," When poisoned bait is used according to the above direction — that is, about one small tablespoonful thrown down on hard earth near the hole, thus scattering the bait, there is no danger of poisoning stock. In cases where it is desired that the prairie-dogs be killed off quickly while the natural food is plentiful, or where a farmer has only a few acres infested with prairie-dogs and does not care to use poisoned bait, carbon bisulphide ("high-life") may be used. This generally kills all of the animals with one application. It is more expensive to use than the poisoned bait. The following directions are recommended by the U. S. Biological Survey: "One ounce (two tablespoonfuls) of carbon bisulphide should be poured on a small piece of cotton waste or other cheap absorbent material and placed well down the hole. Close the hole immediatelv with dirt or sod. How TO Combat Rabbits, etc. 333 Every burrow which shows evidence of being used should b- treated, and all holes should be closed with dirt. One gallon is sufficient to treat from 100 to 130 holes (an av-rage of about 125 holes). This can be accom- plished by one man in 2 to 3 hours. "Less gas is absorbed by damp soil than by dry soil, hence carbon bisulphide is somewiiat more effective after a heavy rain. "Careful and judicious use should exterminate practically all of the animals from the ar;;a treated. Caution "Carbon bisulphide evaporates very rapidly, so it should be kept in tightly corked bottles or cans. It is highly explosive and inflammable and should never be brought near fire." COYOTES Coyotes are valuable animals for destroying rabbits, prairie-dogs and other small predatory animals; however occasionally they become so num- erous as to attack and kill small calves, lambs and kids and to cause much damage by killing chickens and turkeys. The following directions for poisoning coyotes is given by the U. S. Biological Survey: "In poisoning coyotes it should be borne in mind that the animals are of more than ordinary cunning. Their ability to detect the whereabouts of a trap or the presence of poison in bait is remarkable. Great care should be taken in preparing the bait to avoid human scent, for the coyote seems to regard man as his worst enemy. In handling baits do not touch them with bare hands, but use a pointed stick or wooden forceps. "To prepare poiso'ned bait place 3 grains of strychnine in a capsule and insert it into a piece of suet or cow's udder about the size of an English walnut, being careful to remove all strychnine from outside the capsule. Strychnine is very bitter and if not put into capsules will be detected as soon as taken into the mouth, and the animals, becoming suspicious, will not sw^allow the bait, especially if much poisoning has been done in the neighborhood. Baits should be allowed to stand in a wooden bucket about 48 hours before using to make sure that no human scent remains. "Coj'otes can be attracted to tbe poisoned baits by dragging a piece of meat (or fresh cowhide) behind a saddle horse over foothills and across trails where the animals come from the mountains to the valleys for food and water, and then dropping the baits along the path thus made. As the animals cross the path they will follow it and pick up and swallow the poisoned baits, as their attention is on the scent of the meat drag. "Never poison a carcass, but wait until the coyotes have eaten half or more than half of the fress carcass, then place poisoned baits around the carcass, from 20 to 30 feet away. "As coyotes are very fond of fruit, dried figs and prunes make good bait. Unless an attractive lure is placed near the baits to keep the animals busy until the strychnine takes effect, they may get away and go a long 334 Bulletin 81 distance before dying, as the capsule has to dissolve to free the strychnine." It has been found that if poison is placed in a freshly killed animal (jackrabbit, dog, cat or other fresh meat) which is buried in the earth, the coyotes will dig it up and eat it and be killed by the poison, when they would not eat the uncovered bait. ANTS There are many species of ants, but the ones that cause the great- est damage and with which Arizona stockmen and farmers are especially concerned are the larger species of harvester ants. These are the large red ants that do so much damage to field crops, vegetables, young trees and other plants. The writer has seen young fruit trees killed by these pests, which eat the young twigs and buds. Gardens are sometimes ruined by them, the young plants being cut off at the surface of the ground. Fields of beans have been reduced to less than half stand, the young plants having been cut off just as they were breaking through the surface crust. In some of these cases farmers were at a loss to know why there was not a good stand, not having observed that the damage was done by ants. On one farm the writer found that harvester ants were cutting down the young plants in a Sudan grass field as fast as they came up. Harvester ants not only destroy plants but they sometimes do much harm to animals, sometimes killing them. One woman stated that she lost 150 small turkeys that died from the effects of harvester ant bites. These pests often seriously annoy larger animals. A cow may lie down on a nest, when the ants will bite or "sting" her udder and teats, causing sores. Blackleg may also sometimes be traced to ant bites which cause wounds through which the germs find entrance. Harvester ants are also annoying to people, their bites causing pain and sometimes making sores. The effect of an ant sting is similar to that of a wasp sting, but is usually more painful and persistent. Various methods have been used to exterminate harvester ants. Gaso- line, coal oil, crude oil, cyanide of potassium and carbon bisulphide ("high-life") have been employed with varying degrees of success. The best, cheapest and most easily applied remedy for general use is London purple, the active poison in which is arsenic. It varies greatly in effec- tiveness. Only a good grade should be purchased. It costs about 25 cents a pound in 5 pound lots. Sprinkle a small circle of the powder around the opening of each ant nest, putting a little into the hole. A teaspoon- ful is usually sufficient for treating one nest. This should be applied in How TO Combat Rabbits, etc. 335 dry weather, when the ants are activ.^ and when there is no strong wind to blow the powder away. The best time to begin the treatment is wh:n the ants first become active in the spring. Th: application should be repeated at intervals of one week to ten days, as long as ants continue to show up. The poison acts slowly, killing the ants in one to three days. In crawling back and forth across the poison the ants get the fine powder on their hgs and bodies and thus carry it into their nests and track it over their food supply. Ants infesting houses ehould be traced to their nests if possible and destroyed by pouring in a small amount of coal oil or carbon bisulphide. Th:se small ants are valuable in grain or seed bins. They destroy the larvae of harmful insects, especially pea and bean Weevils, and grain weevils. GRASSHOPPERS Grasshoppers are on the whole th? worst, or one of the worst, pests with which the Arizona farmer has to contend. Grasshoppers not only destroy crop-, gardens, and fruit trees, but also do much damage to the range by destroying grass and mesquite bean crops. Fig_ 9. — Turkeys are great grasshopper destroyers. They should be herded in order that they niav keep on the move and also that coyotes may not harm them. Herding an hour in the morning" and an hour in the late afternoon and penning for the rest of the day and at night is a good plan to handle them. Some one in the comnnmity co\ild well make a specialty of raising and herding turkevs, or taking them to raise and market on shares, thus doing a large enough business to afford' to devote his time to it. (Note the boy in the background and also how the turkeys string out in a line). In communities where these pests appear in large numbers and where the region is sparsely settled, it is difficult and expensive for a farmer who is surrounded by uncultivated land to save much of his crop. However, if active measufes are taken in time grasshoppers can be controlled. 336 Bulletin' 81 MEANS OF COXTROL Poultry: Grasshoppers can be controlled and at the sam^ time can be mad." profitable by raising turkey's to eat them. It is a good plan to herd the turkeys on grasshopper ground one to two hours in the morning and again in the afternoon. In this way they are prevented from damag- ing crops and ar^ protected from hawks and coyotes. In order to herd at a profit one should have a sufficiently large flock to make it a paying business. Elach farmer or farmer's wife in a locality can easily raise a few turkeys. As soon as thes3 are large enough to be herded one man can buy them or take them to raise and sell on shares. Usually, as soon as turkeys are large enough to be h-^rded, grasshoppers and other insects have made their appearance. When the grasshopper season is Fig. 10. — Turkeys and chickens thrive well in Arizona, are big assets to farms and are great insect destroyers. over it requires but little feeding to make turkeys ready for market This is a suggestion which every community troubled with grasshoppers should consider, since Arizona climate is favorable to successful turkey raising. Chickens and guinea fowls, when allowed free range, are also very helpful in destroying grasshoppers and other insect pests. Every farm should maintain a good supply of pure-bred chickens. One farmer in a badly infested grasshopper district was protected from these pests by a large flock of White Leghorn hens. Poisoning: In the absence of turkeys, poison baits are economical and effective for destroying grasshoppers. By the use of poisoned bran several How TO Combat Rabbits, etc. 337 farmers in the badly infested areas of Cochise County saved their crops from destruction by grasshoppers in 1916. The following methods of poisoning are recommended by the U. S. Department of Agriculture. Grasshopper baits: "Ninety-five per cent of grasshoppers attacking crops in widely different parts of the country were killed quickly and cheaply by an improved poison bran bait and the Criddle mixture. The important change in the formula is to double the amount of lemons or oranges used in the bait, and to add thes? fruits to the Criddle mixture. The change in the mixture is recommended by the forage crop entomolo- gists of tht department as a result of thorough tests conducted in New England, Florida, California, and Arizona. These tests were conducted in different sections and with many different varieties of grasshoppers to determine, if possible, why the old formulas were only partially effective with adult grasshoppers and even less effective with young grasshoppers, and to find whether the fault lay with the different mixtures or with the way they were used. The entomologists found that adding the fruit to the Criddle mixture and increasing the amount in the bran bait increased the attraction of the bait to the grasshoppers and led them to eat it more readily. Neiv formulas for bran bait and Criddle mixture: The Criddle mixture as modified for use in killing young grasshoppers is prepared as follows: 50 pounds fresh horse droppings. 1 pound salt. 1 pound Paris green. 3 oranges, finely ground. Ordinarily no fruit at all is used in the Criddle mixture, and but three oranges to each 25 pounds of bran bait. "The poison bran bait, as modified with the especial object of killing young as well as old grasshoppers, is prepared as follows : 25 pounds wheat bran. 2 quarts cheap molasses or blackstrap. 1 pound Paris green. 6 oranges or ^^nnons. "Thoroughly mix together the bran and Paris green in an ordinary washtub or other vessel. Into a separate receptacle, containing the mo- lasses or sirup, squeeze the juices of the fruit. Chop up finely the skin and pulp of the fruit and add to the molasses. Dilute with 3 gallons of water and mix with the bran. Add enough more water to bring the whole to a stiff dough. "The bait should be sown broadcast early in the morning, before sunrise, in strips 1 rod apart, over the area to be treated, so that the grasshoppers may be attracted to it before it dries out. The most satis- 338 Bulletin 81 factory method of distributing the bait is to sow it from the rear end of a buggy." Farmers in the Rucker district of the Sulphur Spring Valley report that th?y have secured best results from poisoning by putting out the poisoned bait between 1 1 a. m. and 1 1 p. m. At this time of day, during the hot and dry days, the grasshoppers seem unusually thirsty and will travel a long distance for the moist bait. Hopperdozers: Grasshoppers are found usually in large bunches soon after hatching out. If these are discovered before they begin to fly they can be exterminated cheaply by the use of 'hopperdozers,' provided con- ditions are favorable for their use. (For further information on hopper- dozers see Timely Hint No. 104 of the Arizona Experiment Station). When grasshoppers are hatched out in areas that contain much dried grass, the pests may be destroyed by burning off the grass. A circle on the outside should first be set on fire so that the hoppers cannot escape. In regions where grasshoppers are likely to occur the people should keep a strict lookout in the spring and early summer in order to determine where they first appear, so that control measures may be applied before the young grasshoppers begin to fly or destroy vegetation. Clubs should be formed for this purpose and regular reports made by the members in order that there may be community cooperation. REFERENCES For further reference and reading matter on the subject of agricultural and range pests the reader will find the following publications very interest- ing and instructive : Farmers' Bulletin No. 335 : Harmful and Beneficial Mammals of the Arid Interior. Farmers' Bulletin No. 702 : Cottontail Rabbits in Relation to Trees and Farm Crops. Farmers' Bulletin No. 670: Field Mice as Farm and Orchard Pests. Farmers' Bulletin No. 369: How to Destroy Rats. Farmers' Bulletin No. 587 : Economic Value of North American Skunks. Farmers' Bulletin No. 747 : Grasshopper Control. Bureau of Biological Survey Bulletin No. 20: Coyotes in their Economic Relations. Bureau of Biological Survey Bulletin No. 40: A Systematic Account of the Prairie Dogs. Bureau of Biological Survey — Circular No. 61 : Hawks and Owls from the Standpoint of the Farmer. Reprint from Yearbook for 1907. U. S. Department of Agriculture. The Rabbit as a Farm and Orchard Pest. University of Arizona Agricultural Experiment Station Bulletin 82 Rootstocks on seedling Johnson grass plant Johnson Grass Control By H. C. Heard Tucson. Arizona, December 1, 1917 UNIVERSITY OF ARIZONA AGRICULTURAL EXPERIMENT STATION C.UVKRXIXC". BOARD ( Rkcents ok the University) lix-Officio His Excellency, The Governor of Arizona The State Superintendent of Pur.i.ic InstructioxN .Ippoiutcd by the Governor of tlic State William V. VVhitmore, A. J\I., M. D Chancellor Rudolph RasmEssEn Treasurer William J. Bryan, Jr.. A. B Secretary vv^illiam Scarlett. A. B.. P.. D Regent John P. OrmE Regent E. TiTCOMB Regent John W. Fi.tnn Regent Captain T. P. Hodcson Regent RuFus B. \ii.\ KlEixsmih. A. M.. Sc. D President of the I'niversitv A^rieultiiral Staff Rop.ERT H . I'oRisEs. Ph. D Dean and Director John J. Thornuer. A. M Botanist Alp-Ert E. Vinson. Ph. D Biochemist Clifeord N. Catlin. A. M Assistant Chemist George E. P- Smith. C. E Irrigation Engineer Frank C. Kelton, M. S \ssistant Engineer George F. Freeman, Ph. D Plant Breeder Walker E. Bryan. M. S Assistant Plant Breeder Stephen B. Johnson. B. S- Assistant Horticulturist Richard H. Williams, Ph. D Animal ?Iushandman Walter S. Cunningham. 11. S Assistant Animal 1 ln>handnian Charles R. Adamson. B, S., .\gr Instructor, Poultry 1 luslxuidry Herman C. Heard, B. S. Agr Assistant Agronomist Austin W. Morrill, Ph. D Consulting Entomologist EsTES P. T.VYLOR, B. S. .\gr Director Extension Service George W. Barnes. B. S. .\gr Livestock Specialist, Extension Service Leland S. Parke, B. S State Leader Boys" and Girls' Clubs Agnes A. 1 1 unt Assistant State Leader Boys' and Girls' Clubs I\L\RY Pritxer Lockwood. B. S State Leader Home Demonstration Agents Imogene Xeely County Home Demonstration Agent. Maricopa County IIazEl Zimmerman. .. .County Home Demonstration Agent, Southeast Counties Arthur L. Paschall. B. S. Agr County .\gent, Cochise County Charles R. Fillerup. D. B County .\gent. Xavaj(j-.Vpache Counties Ai.AXDO B. Ballaxtvxe. B. S County A-ent. (n-aham-(^ireenlee Counties W. A. Barr, B. S County Agent. Maricopa Count\ W. A. Bailey. B. vS County Agent, ^'uma County DeLore X'ichols, B. S County Agent. Coconino County Hester L. Hunter Secretary Extension Service Fr.\xces M. Wells Secretary .-Xgricnltural Experiment Station The Experiment Station offices and laboratories are located in the University Buildings at Tucson. The new Experiment Station Farm is situated one mile west of Mesa. Arizona. The date palm orchards are three miles south of Tempc (cooperative. U. S. D.-A.). and one mile southwest of Yuma, Arizona, respec- tively. The experimental dry-farms are near Cochise and Prescott, Arizona. Visitors are cordially invited, and correspondence receives careful attention. The Bulletins, Timely Hints, and Reports of this Station will be sent free to all who apply. Kindly notify us of errors or changes in address, and send in the names of your nei.ghbors, especially recent arrivals, who may find our pulilications useful. Address, The Experiment Station, Tucson, .\rizona. PREFACE For about thirty years Johnson grass has s;)rea(l, at first slowly and then with increased rapichty. at altitudes of -lOOO feet and below, throughout Arizona. In some cases its introduction was no doubt acci- dental : liut in other instances it is known to have been planted by irrigatiui^ farmers as a ha)- crop, and by stockmen as an emergency forage. Johnson grass is therefore now well distributed over grazing ranges, along" water courses, and throughout the lower irrigated valless of the State. W hile this plant, with its tk'shy rootstocks, may serve beneficially as an emergency forag;e, and as a soil binder to prevent erosion, its main effect is as a j^estiferous weed in irrigated valleys, l)reventing- the profitable culture of simimer cro])s and depreciating land values seriously. The State has endeavored to regulate this weed by means of a law- prohibiting all traf^c in Johnson grass plants and seed, or its culture, but with little effect upon the pest. Many attempts have been made by the farmers themselves to exter- minate or control Johnson grass. Continuous dry fallowing of infested fields is jiracticed ; sheep are to some extent being used along ditches and weedy roadsides ; and "easy methods" of soil treatment by chemicals, steam, or otherwise, have been proposed ; but more and more it is being found that intelligent and persistent cultural methods base

  • Z CJ ^ ^ H I 1 C 1J ;/! E "l- E 03 4; >, HH i; 5; 0 U o E -o E 3 u 1-4 03 t ■*-• 0 4. >• a in -0 E j: rt «j > rt u 0. 43 •^ r 'x >-< >. be t/] J3 15 ct: <5 u rt CJ 3 5: s so s The results of these ferti- lizer tests were very hard to measure. On the first four plots such an irregular stand was secured that no records were kept. The records on plots five to eight are of little value because of the many fac- tors affecting the results. There is no definite period of maturity in lettuce. It increases in size for a long time after it might be mar- keted. Practically any of the soil in the Salt River Valley is strong enough to grow large-sized heads if it lias time enough. A good method of meas- uring the effects of the fer- tilizer was discovered too late to be used. Weighing a certain number of the most mature heads from each plot at regular inter- vals, would have given a comparison of yield as well as earliness. The only conclusions that can be drawn from the fertilized plots are that the ])lot receiving the manure at the rate of 20 tons to the acre was the first to come to maturity and produced the best lettuce. The ma- nure put some sour clover seed in the ground, but af- ter the thinning no trouble was experienced from this. Arizona AgricuIvTuraIv Experiment Station 441 Plots 5 to 8 were divided into thirds so that three strips 23.9 feet by 192 feet were planted in three different ways. The first strip was planted two rows on the ridge. The second strip was planted with one row on a ridge, and the third was planted level and flooded. These three ways of planting have all been used to some extent in Arizona. Of the three methods only the first two are at all satisfactory. The flooded seed had dif^culty in germinat- ing unless the ground was moist on the surface, and the plants did not make as good a growth after they got started. Planting two rows on a ridge was satisfactory, but involved more hand work in cultivation. The single-row system seems to be best adapted to growing lettuce under field conditions where the price of land does not warrant the added expense of hand cultivation. SWEET POTATO STORAGE The results of the preliminary tests in the storage of sweet . potatoes at the Yuma Date Orchard are interesting. The potatoes were stored between layers of straw and covered with a thick layer of the same material. One pile was handled in the usual rough way and carried from the field in sacks. The other pile was care- fully placed in crates; cured in a room kept at a temperature be- tween 85° to 90° for one week, and then piled. The potatoes were taken out of storage April 18th with the following results : Pile No. 1 had in it 106 pounds of potatoes, of which about one-half was marketable. This was 38% of the 278 pounds put in the pile. The second pile contained 74 pounds of potatoes^ of which 757© were marketable. This was 48% of the original 154 pounds put in the pile. Mr. Aepli in reporting on the potatoes when they came out of storage says, "It seems that every potato under two inches '-i diameter shriveled and every one over that size except the bruised ones kept very well." From this it can be seen that in putting sweet potatoes out of doors the dry air is suf^cient to cure them and that to prevent excessive drying a layer of dry soil should be thrown over the pile after the curing had taken place. This work is to be continued during the year 1918. S. B. Johnson, Assistant Horticulturist. 442 Twenty-e;ighth Annual Report THE DATE ORCHARDS The date crops of 1915 and 1916 were especially interesting because the conditions governing them ranged from the best to the worst within our experience. The crop of 1915 was not only very heavy, some 5100 blooms at the Tempe orchard having been pollinated that year ; but the nearly rainless fall season was perfect for ripening purposes. The yield of all varieties ripening at Tempe was therefore heavy, and there was almost no loss due to souring or to the fungus spot disease. In 1916, however, the crop was light, only 2173 blooms having been pollinated, and the heavy rain of September 8, with subse- quent humid weather, having resulted in very large losses by sour- ing and fermentation of partly ripe dates. The fungus spot disease, to which the Deglet Noor is especially liable, also caused large « losses this year.- As in previous years, artificial ripening processes were em- ployed both for late varieties and to save the fruit which would otherwise spoil in wet weather. These processes consist, first, in some cases, in subjecting the sufficiently matm-e fruit to an atmos- phere of carbon dioxide gas for 18 to 24 hours ; and, second, in all cases, in subjecting the dates to certain degrees of heat for varying lengths of time. Conditions of humidity under which heating takes place have also much to do with the quality of the product. Each variety of dates seems to require a certain combination of condi- tions to ripen well and must therefore be individually studied. Deglet Noor, for instance, is first exposed under slight pressure lo carbon dioxide, is then heated on trays in a ripening chamber J t 45 to 49 degrees C. for 48 to 60 hours. All varieties are now pas- • teurized before packing in order to destroy eggs, larvae, and insects that may be present. This is done by heating at 65 degrees C. for two to four hours, according to size of dates. Much experience has been gained also in packing and market- ing the crop, most of which has been sold for immediate use as fresh fruit. Most varieties were packed in one-pound baskets and shipped in five or fifteen-basket crates, lined with unbleached mus- lin to exclude insects. Thus prepared for market the crop has ])eon shipped successfully all over the United States and to Canada, and even as far as Denmark. One shipment was sent to San Francisco, thence to Honolulu, and back to San Francisco, before being deliv- ered to the addressee. Nevertheless, it has been recommended that Arizona AcriculturaIv Experiment Station 443 the product be considered fresh fruit, and be consumed soon after leaving the orchard. In dry, cool weather these dates keep well, but in warm and humid weather some varieties sour and mold readily. Semi-dry dates like the Deglet Noor were packed in tin boxes, and in that shape will last for months ; while the dry or bread dates will last a long- time with comparatively little care. The ])rices charged for the product were reasonable — much less than could have been gotten for a market novelty, the desire being to avoid inflated estimates of the possible profits from date culture. Thus, fresh dates of good quality packed in baskets were delivered at the local express office, — five-pound crates for $1.00 and 15-pound crates for $2.50. Deglet Noors in 14-ounce tin boxes were sold three boxes for $1.00. A few special lots of dates were sold at higher prices and inferior grades for less. Following is a statement of sales for the graded crop of a few leading varieties for the two years under consideration : DEGLET NOOR, 40 TREES 1915 47 ho.yes @ 40c 59 35 745 33 1,318 30 163 20 96 V2 10 2,428 i/„ /3 18.80 20.65 248.35 395.40 32.60 9.65 $725.45 1916 36 225 1 2 6? 1/2 7 16 348 Vo bo xe.s @ 35c 33 1 /3 30 25 20 15 10 $ 12.60 75.00 .30 .50 12.30 1.05 1.60 103.35 BENT KEBALA, ONE TREE 191.') 1916 76 l)(>xes fi> 20c $14.20 146 l)t)xcs ^ 20c $29.20 31 •' • 16 2/3 5.15 47 162/3 7.82 23 10 2.30 107 $19.35 216 $39.32 H.W.VNV, 17 TREES 1 91 r, 1916 85 1)ONOS ((f 25o S 21.25 "3 1 .002 20 200.40 573 2.785 16 2 3 464.15 1.128 3 10 .30 7 2 3.875 .$686.10 1.803 $ 23.25 114.60 188.00 1.05 .20 $327.10 444 Twenty-eighth Annual Report NAZE EE BACA, TWO TREES 1915 1916 20 boxes @25c $ 5.00 114 i4 16 2 /3 19.00 139 a 20 27.80 1 n 10 .10 274 $51.90 RHARS, ] 159 TREES 1915 1916 2,361 boxes fx) 20c $ 472.20 384 boxes @ 20c $ 76.80 9,496 *( 16 2 /3 1,582.35 2,481 •• 162/3 413.50 1,4351/2 ti 10 143.55 994y2 " 10 99.45 13,2921/2 $2,198.10 I 3,859^/2 MAKTUM, THREE TREES 7?, 20 S 16 2 3 71/2 •• 10 1321/2 1915 82 104 37 223 lbs. @ 25c 20 $11.00 14.60 1.35 .75 $27.70 ITIMA, FIVE TREES 1916 16 2/3 $20.50 20.80 6.15 30 lbs. @ 20c 47.45 KUSTAWI, SIX TREES 1915 25 lbs. @ 20c 27 " 16 2/3 1 1/2 " 10 531/2 $5.00 4.50 .15 $9.65 1916 235 lbs. (a 20c 53 " 16 2/3 4 " 10 292 $589.75 1915 25 lbs. @ 25c 24 " 20 $6.25 4.80 1916 137 lbs. @ 20c 5 •• . 16 2/3 142 I, ONE TREE 1916 $27.40 .83 49 1915 $11.05 MENAKHEl $28.23 $6.00 $47.00 8.83 .40 $56.23 It is of interest here to note the gross commercial results for the whole crop for three years, the scale of prices for the product remaining the same for that period of time : Average Blooms Cash returns pollinated receipts per bloom Crop of 1915 5.100 $4,734.10 $.93 Crop of 1916 2.173 1,563.79 72 Crop of 1917 : 3.093 4.771.74 1.54 Arizona Agricultural Kxi-krimlnt Station 44? In 1915, with the palms blooming heavily and \vt:!.h a good season, good gross and average returns were secured. Jn 1915, with scant blooming and bad weather, low gross and average re- turns were received. In 1917, with a luvv blooming record but with perfect weather and no waste, a high gross and average re- turn was secured. It is also of interest to inspect the statement of results for the crops of 1915 and 1916 prepared, packed, and marketed in this manner, as given in Table VI by Mr. F. H. Simmons, foreman of the Tempe orchard. This statement is by no means conclusive as to the relative merits of all varieties included therein. Some varieties are rep-^- sented by only one or a very few trees ; and others, while perform- ing poorly at Tempe, are known to do well at lower altitudes. Yet, with the experience of other years relative economic mer- its of the different varieties are to some extent indicated. For instance, Amari gave good results in 1915, its merit being that its extreme earliness gives it a market at a time when other varieties are not yet ripe. Early rains in 1916 soured the crop almost en- tirely. Bent Kebala is a date of good quality, affording good incom--, ripening late both years, and thus escaping September rains in 1916. Deglet Noor gave an almost perfect and very profitable crop ■of dates in 1915. Although these dates fcjr Deglet Noor were distinctly second class as grown at Temi)e, yet their flavor and their good keeping qualities made them desirable and readily marketable. In 1916 this variety was nearly all sptnled by the fungus spot dis- ease, which is favored by wet weather. A few late Deglet Noors were ripened artificially and marketed. Hayany in 1915 yielded an almost perfect crop of fine dates, which in our experience, are preferred by a majority of buyers both on account of the appearance and the quality of the fruit. In 1916 the croj) was diminished considerably by souring, and fruit started to distant markets was much of it at first reported sour upon receipt. Later in the season, howover, few complaints were received. Itima marketed well in 1915. but was adversely afifected by the wet weather the next year. Kustawi did not bear much in 1915. but set a large crop m 1916 which, on account of the lateness of the variety, escaped the humid weather and ripened well. 446 Twe:ntv-kighth Annual Report Khardrawi, a late date of excellent quality but bearing- lightly, was not injured by the wet weather. Maktum, another late date of excellent quality but trees not bearing heavily, was not injured by September rains. Menakher bore well in 1915, but none of the crop was saved the following year. TA15LE \I. — SUMMARY OF DATE CROPS BORNE; AT THE TEMPE ORCHARD, 1915 AND 1916, BY VARIETIES 1915 1916 No. of trees Crop har- vested Cash rec'd No. of trees Crop har- vested Cash rec'd Azcrza 2 5 2 4 ■ 1 2 1 1 2 2 4 45 1 1 1 1 17 3 4 1 5 1 1 6 1 1 4 2 r 2 342 Va 37 1481/2 21 6 107 29 85 711/2 104 11 813 24 81 54 7 3875 47 1391/2 53 223 9 3 531/2 5 2 43 14 361/2 $ .35 59.40 6.75 26.10 j.yo 1.15 19.35 18.05 7.95 18.25 1.95 81.30 725.45 3.30 6.55 9.95 1.25 686.10 8.55 22.95 9.75 47.45 1.50 .60 9.65 l.(M) .35 8.20 2.35 6.45 5 2 1 2 1 2 2 4 39 1 1 17 3 1 1 1 1 1 5 1 1 ? 1 3 2 ' ' 2 1 171/2 59 341/2 123 216 26 301/2 84 154 21 3431/2 23 50 1803 103 1231/2 16 13 121/^ 34 30 62 5 292 13 44 70 22 6 $.... Amari 3.50 A'oochet 10.63 Arcchti Andandon 6.88 Asrherasi /\niri 12.30 Bent Kebala Boo Affar 39.32 Beed Hammam Bread dates 4.83 3.05 Biirni 16.57 Berhi Baguin Jurghi Culls Deglet Noor Deglet Beida Doonga Dishtari 29.70 3.73 103.35 4.46 Oashv Gush Havanv 9.50 686. lU ITalawi 16.80 ["Ipimraia TIanirava 23.61 Hellawee 3.20 Hellali Halooa Htirsliut 1.70 1.25 6.21 1 1 i m a 6.00 Tteem JoIkt 12.40 Karooij Kes1)a .93 Kustaw i 56.23 Khalt Khir 2.40 Khadrawi 7.57 Koroch Kaharaf?) Kaiby 12.53 3.86 1.20 Arizona AgricuIvTural Experiment Station 447 TABLE VI. — Continued No. of trees 3 1 1 1 3 2 1 8 5 2 2 1 162 6 1 3 1 4 6 3 4 4 2 5 1 1 Crop hai-- vested Cash rec'd No. of trees Crop har- vested Cash reo'd Karba TChpclrwet^ 49 1321/2 3 68 16 83 274 59 170 168 85 82 40 13,2921/2 37 2 10 28 96 V2 140 337 3431/2 511/2 43 4 441/2 55 54 7 37 18 11.05 27.70 .60 13.15 2.85 16.05 51.90 10.60 34.45 21.30 15.45 6.75 3.20 2,198.10 6.80 .35 1.85 3.55 6.05 65.10 25.20 61.15 62.45 S.40 8.05 .80 7.75 10.75 11. QO 1.30 6.75 3.20 159 1 9 142 595 4 62 26 21 119 53 46 111/2 38591/2 5 159 10 7 71/^ 86 70 50 134 22 48 25 38 14 8 22 4 .20 1.56 A/raktiim 28.23 ATenakher Mixed Dates Nakelet Feraoon Nakelet el Leef IMo Name 59.50 .30 11.93 5.13 IM-i?! el Raca Nesheem 3.66 Oga or Saidy Purdy Seedling Rhazi 20.70 9.S6 7.85 Retbet Regaia Remta 2.02 Rhars 519.75 Roghm Gazal Seedlinff .50 Seba Loosif Saver Seba Redraa 1.00 30.53 Safraia 1.00 Saidv f not) .77 Snkeri .25 Timdjouert (Red)... Timdjoiiert (Yellow) Tadala- 16.30 Tennessini Tafizooin 12.60 Tazizaoat 8.86 Tcntebusht Taurarhet Takadet 26.00 Totee 4.40 Tamzoohart 'Toorekhet 9.57 4.70 Tozerzaid Khala Unknown varieties. . . Zerza 7.?,7 2.80 1.60 Zrai 4.20 Zehedi 15-7 .80 5-6 Rhars ripened a heavy crop in 1915, nearly all of which was marketed; but in 1916 about three-fourths of the crop cracked open and soured on the trees. Timdjouert (red and yellow) yielded fairly well in 1915, but all spoiled in September of the following year. Takadet, a late variety, ripened its crop both years. 448 TwicxTv-i;i(;irrH Annual Rkport Dry dates in general came through the rainy season success- fully. These observations indicate that the climate of the region, evjn with the assurance afforded by ripening operations indoors, to a considerable extent controls the harvesting of the date crop, a fact which, however, is not in itself unusual or discouraging inasmuch as the date growing regions of the Old World are to some extent similarly affected by rains during the harvest season, especially on the Persian Gulf, Avhere, it is stated, some years an almost complete loss of the date crop is caused by untimely rains. At the present time cultural, packing house, and marketing experiences with date palms at the Tempe date orchard, place Hayany, an Egyptian variet}', distinctly in the lead. This variety is a very heavy bearer. The fruit is large, easily picked and cheaply harvested. It ripens well on the tree and in adverse seasons lends itself readily to artificial ripening operations. The finished product presents and attractive appearance and the cpiality is fairly good. The American public has also expressed in a majority of cases a distinct preference for this variety. Rhars also is a heavy bearer and the fruit is liked by many consumers. It ripens scatteringly on the tree, however, and is not easily picked. It sours very readily in wet weather. Deglet Noor has given satisfactory results at Tempe only dur- ing the exceptionally dry and favorable autumn of 1915. It is not recommended for planting in the Salt River Valley, although un- doubtedly a superior variety at lower altitudes having a longer season and a drier climate. Other excellent -varieties are represented by few trees only, some of which are still young and presumably not yet in full bear- ing. Commercial results with them, while interesting, are not necessarily conclusive. Table VII gives a summary of results witu a selection of the most promising varieties at Tempe, giving, in addition to data already stated, average results per tree. COLD STORAGE OF DATES Some attention has been devoted during the year to the cold storage of fresh dates in order to prolong the marketing season for a perishable product, notice having been directed to the subject by the experience of Messrs. F. W. Butler and Son at the Ferry fruitstands in San Francisco. These gentlemen observed that dates being sold by them from day to day on the San Francisco market Akizoxa Agricultural Experiment Station 449 TABLK VII.— summary of TEMPE DATF, orchard sales, 1915 AND 1916 1915 1916 Average value per tree Variety Trees Pounds Values Trees Pounds Values 1915 1916 Hayany Rhars Maktuni Deglet Xoor.. Bent Kebala.. Hamraya .... Kustawi Sayer Takadet ]\IenaklKT . . . 17 3.875 $686.10 162 13,292 2,198.10 3 49 11.05 45 725.45 1 107 19.35 1 53 9.75 1 53 9.65 3 1(1 1.85 1 55 10.75 1 ]?,2 27.70 17 1,813 $327.10 159 3,859 519.75 3 142 28.23 39 348 103.35 1 216 39.32 1 123 23.61 6 292 56.23 3 159 30.53 1 134 26.00 $40.36 $19.24 13.57 3.27 3.68 9.41 16.12 2.65 19.35 39.32 1.61 9.37 .62 10. IS 10.75 26.00 TABLE Vlll. — RESULTS WITH COLD STORED DATES Stored Examined Sept. 20 1916 Nov. -1 1916 1 Jan. 20 1917 Feb. 7 1917 Mar. 11 1917 Mav2 1917 Nov. 17 1917 Rhars Perfect i condi- tion . . Perfect condi- tion Perfect condi- tion Musty taste but no mould Good condi- tion Few stale berries sugared mostly marketable Hayany .... 1 Few sour dates Mouldy and wet 58% spoiled All mouldy and spoiled. Bent Kel)ala In per- fect condi- tion , Slightly mouldy and stale Takadet ... do. Mouldy !)Ut sweet — unmarketable /Tenessim . . . do. Slightly moukfy and stale Saidy do. Slightly mouldy and stale Hamraya . . . do. Mouldy and quite stale Not named. . do. 1 box mouldy. 1 box in good con- dition. Iteem Johei do. Sugared — in per- fect condition. Purdy seed- ' lins; do. Quite stole. 450 Twenty-eighth Annual Report I'.ept well in dry cold storage. Crates of different varieties of dates packed as for shipment were therefore placed in dry cold storage in Phoenix at a temperature of 36-38 degrees F. The date of stor- age was September 20, 1916, and the samples were examined at various times during a period of fourteen months with results indi- cated in Table VIII. All the varieties tested except Hayany kept well until after holidays, and Iteem Joher, rich in sugar, kept perfectly for fourteen months. Rhars kept fairly well for this time also. These observa- tions indicate that many varieties of dates ma}^ be harvested and held for sale as fresh fruit, thus avoiding overstocked markets at the height of the harvest season. EVAPORATION AND COED STORAGE A further experiment with the Hayany crop of 1917 was con- ducted by evaporating several samples of fresh fruit to 90%, 80%, 70%, and 60% of fresh weight, and then putting them in dry cold storage at about 34-36 deg. F. These dates were picked October 19 and were examined January 23, 1918, in comparison with un- evaporated fruit similarly kept. Table IX. gives the results of this experiment. TAP,I,E IX. — RESULTS WITH CC Sample Picked Examined Fresh fruit Oct. 19 Jan. 23 1917 1918 90% i resh vvt. a it 80% ti li ti i( 70% it a a ti 60% a it (t a Condition Plump, moist, 947c mouldy Fresh, firm, 7% mouldy, flavor excel- lent Wrinkled, no mould, prime quality Semi-dry, no mould, superior quality Sticky-dry. no mould, very sweet, good quality NOTE: — April 20,1918, after six month.s in cold storase, these dates were .sub- stantially in the condition described above. Occasional fruits evaporated to 1)0^ of the original were specked with mould, but after removing these the rest of the package was edible and marketable. Those evaporated to 80% and 70<"^ of the original weight were still in prime condition and of fair flavor. The uni)rocessed fruits used as a check were a mass of mould. Trial baskets removed from cold storage and exposed to warm dry air after one week are in good condition. — A. E. V. These statements indicate that the fruit would have kept well at about 85% of its fresh weight; while at 70-80% it kept perfectly and Avas of superior quality after three months of storage. ROOTING OF date; p.klm sucke;rs A partial review of distributions to individuals of suckers from the date palm orchard indicates that nearly 95 ])ercent of such dis- Arizona Agricultlkal Exi'Krimext Station 451 tributions have perished, partly, without doiil^t, because of the sappy condition of suckers from the water-soaked Tempe Date Orchard, and partly perhaps also because of neglect on the part of some of those receiving them. Results at the Yuma Date Orchard, where some consignments of these suckers were sent were some- what better, but yet far from satisfactory. Following these experi- ments, distributions of date suckers from the Tempe Date Orchard have been stopped for the present, and suckers are being rooted by the new method developed by the United States Department of Agriculture in the Coachella Valley. Three propagating houses ha\ e been constructed at the Salt River Valley Farm and the Yuma Date Orchard and additional capacity will be provided to take care of other suckers intended to be grown in Arizona. It is particularly important at this time thus to safeguard every date palm sucker of value, inasmuch as the French embargo upon further exporta- tions of suckers from the Old World, as well as European war con- ditions, which obstruct importations from any part of the Old World, have thrown us entirely upon our own slender resources for the propagation of desirable varieties. propagation of deglet xoor seedlings Professor Freeman's experiment in fixing Deglet Noor palm seeds true to seed is being cared for at the Tempe Date Orchard. It will require some years for the first generation of seedlings to come to fruition and until then experimental work with the subject is limited simply to the culture of first generation trees. For de- tails of this experiment see the Tw^enty-first Annual Report, page 384. R. H. Forbes, Director. PLANT BREEDING ALFALFA In the alfalfa breeding work live series of plots are now under test. One of these is located within the covered garden on the University grounds, at Tucson, and the other four on the experi- mental farm near Mesa. In the series at Tucson a large number of individual plants are being tested as mother plants. Each indi- vidual is cut as soon as it comes into maturity, (early blooming stage), and weighed. By this means it is hoped to tind high yield- ing strains having the power of rapid growth and quick recovery after cutting. In the 121 days, from August 20th to December 1st, a number of plants matured three cuttings, whereas, others ma- tured only one. The majority of the plants matured two cuttings, the first being made about September 20th and the second about October 25th to November 10th. A strain of alfalfa ( Xo. 17) originating from a single plant selection in 1909 has been maintained and increased on account of the good yield and high quality of hay produced by it. Apparently, however, the mother plant was a hybrid, for the offspring was by no means uniform in type. It was decided therefore to make pedigree selections within this strain. Seeds from 25 selected mother plants were therefore secured and sown in plant rows at the Mesa Farm. The differences in average 3rield per plant for these rows are so interesting that they are given in Table X. in the order in vhich they occurred in the field. Rows Nos. 444 and 462 may be noted for their high yields. whereas, rows Nos. 447 and 461 are correspondingly low in yield. Yields for the 18 one-fourth-acre plots at the Mesa Farm which were planted in the fall of 1916 were recorded during the present- crop season. Table XI. gives a summary of the results. In the fall of 1917, 36 pedigree races in rows, each 600 feet long, were planted on the Salt River Valley Farm. This series con- stitutes the second elimination test of a large number of plant rows previously tested on the trial grounds at Tucson. In addition to these a series of 22 one-eleventh-acre plots were planted on the Salt River Farm. These plantings constitute a series of increase plots for testing out on a larger scale the elite pedigree races which have already withstood a first and second eliminati'm test in rows. Arizona AcRicui/ruRAL Experiment Station 453 TA1;LIC X. AVKRACK VIKLI) I'KK TUAXT, PIvDIC.RlCE ALFAL,FA, SAlVf RlVER \ALLi:v FARM, 1917 >«^-i* No. No. Cutlinij Cutting Cutting Average Plant.s Aug. 17 Sept. 20 Nov. 15 lb. lb. lb. lb. 442 155 .31 .19 452 156 .37 .44 .57 .46 451 148 .33 .45 .55 .44 450 160 .41 .51 .59 .50 449 140 .30 .48 .60 .49 448 150 .39 .51 .60 .50 . 447 153 .33 .42 .52 .42 446 154 .43 .52 .59 .51 445 15S .34 .51 .58 .4^ 444 141 .47 .52 .59 .53 443 147 .34 .45 .56 .45 441 146 .36 .56 .64 .52 440 143 .34 .54 .63 .50 464 151 .21 .31 .37 .30 463 146 .24 .48 .42 .38 462 152 .31 .57 .46 .45 461 145 .23 .40 .37 .33 460 152 .31 .52 .47 .43 459 145 .27 .44 .43 .38 458 155 .27 .41 .38 .35 457 148 .25 .44 .37 .35 456 80 .33 .48 .47 .43 Peruvian 133 .30 .45 .40 .38 455 84 .20 .32 .48 .33 454 155 .23 .39 .37 .33 453 149 .25 .47 .51 .41 TABLE XI. — FIELD PLOTS OF ALFALFA, SALT RIVER VALLEY FARM, SUMMER, 1917 No. Variety No. nlots Average total yield lbs. per A. 7? Arabian 3 10765 41 European ? 16223 39 Peruvian 6 14394 11 Variegated 3 13807 24 .Mgerian 2 15127 35 Siberian 1 9465 27 'J'urkcstan 7723 As the productivity and hardiness of Peruvian alfalfa is be- coming better known throughout the Southwest, the ptjpularity of this variety is increasing ra]:)idly. The true Peruvian alfalfa may be recognized by its somewhat stifif, upright hal)it, narrow leaves, flark ]nirple flowers, and a marked pubescence (short Inie hairs), on the upper parts of the stems and on the yotmg leaves. vSomc confusion has arisen on account of there having been ])ut on the 454 Twenty-eighth Annual Report market a so-called smooth Peruvian alfalfa. However, that the superiority of the true Peruvian variety is now generally recog- nized by the public is reflected in the fact that purchasers are willing to pay approximately double the price of ordinary seed to dealers who can guarantee to furnish seeds of the true Hairy Peru- vian alfalfa. In order to meet the demand for information concerning Hairy Peruvian alfalfa this department has gathered together the results of its experiments and experience with this variety in the last eight vears to be published as Timely Hints for Farmers No. 132. Those desiring copies of this publication may obtain same by addressing the Arizona Agricultural Experiment Station. BEANS Investigational work with beans during the past season has been confined to genetic studies. Hybrids of the third generation have now been secured and they furnish material for the biological analysis of the varieties entering these crosses whereby the genetic formulae of each are being resolved and tabulated. When the genetic formulae of agricultural varieties of plants in general can be written in much the same manner as the chemical formulae of organic compounds, the basis of a rationale for constructive plant breeding will have been laid. Owing to the great demand for information concerning the culture and varieties of Southwestern beans and teparies, the orig- inal editions of the two publications (Bulletin No. 68, Southwestern Beans and Teparies and Timely Hint No. 92, The Tepary, A New Southwestern Legume) relating to this subject were quickly ex- hausted. To meet this demand Timely Hint No. 92 was revised and reprinted April 20, 1914, and later to fill the need for more detailed information Bulletin No. 68 was enlarged to include ex- perimental and other data relative to beans and teparies, which' have accrued in the last few years, and republished January 15, 1918. The tepary bean, first introduced by the Arizona Experiment Station, has now become well established in the agricultural and seed trade. The common stock is now, however, beginning to be replaced by an improved variety (No. 17) which was produced by selective breeding by this department. Those desiring seeds of this new variety may obtain a list of the growers of the same by addressing this department. Arizona Acricultural Exi'i:ki.mi:n r Station' 455 CORN The work with corn this year has been confined to that part of the project relating to the resistance of the pollen, to heat and dry air. Apparently varieties difTer in this respect. Methods for the artificial germination of corn pollen have been successfully tested out and a beginning of systematic research is being developed on the part of the project. The Papago sweet corn put out by this department (See Bul- letin No. 75) has now found its way into the regular seed trade and is becoming popular in many parts of the Southwest. An unex- pected development for this variety is its high promises as an ensilage corn in the high altitudes of northern Arizona, and in parts of the middle and eastern states where it has been tested. DATES The orchard of seedling Deglet Noor dates planted at the Tempe Date Garden, April 1-25, 1912, bloomed and bore fruit for the first time during the present season (1917). At this time 235 trees are alive and in a healthy growing condition. Of the 49 trees blooming, 22 were females and 27 were males; 21 females bore fruit. Careful notes were made upon these October 24th, at which time the fruits on a number of the trees were ripening. It is inter- esting to note that 10 of the 21 females bore fruit as light in color as the Deglet Noor female parent, whereas, the other 11 had fruits which were deep red when matured, and black when ripe. These facts offer the first step in the genetic analyses of the Deglet Noor date, for they indicate that the Deglet Noor variety is homozygous for the light colored fruit, whereas, the Deglet Noor male seedling used as a parent in this cross, had for a male parent some dark colored date. They furthermore indicate that the dark color of certain dates (Plyani, Perdy, etc.) is a unit character. As to quality of fruit, date of ripening and response to the stimulus of heat in artificial ripening, these seedlings varied widely. The quality was for the most part poor, a fact which further emphasizes the futility of attempting to start commercial date orchards from seedling trees. There were, however, one or two rather promising trees which indicate the possibility that by the time all of the 235 trees have proven their characters, an amply sufficient number may be found well worthy of selection for breeding stock in the further I'rf)secution of this ])r()ject outlined in 23rd .Annual Report, p. 384. 456 TwENTv-EiGiiTii Annual Report WHEAT The wheat work during the past year was confined to the economic phase of testing and selecting ])romising strains of the third and fourth generations of the wheat hybrids made in the summer of 1913, to genetic studies in wheat and to the compilation of data already secured. Two scientific articles originating from this data (G. F. Freeman, Linked Quantitative Characters in Wheat Crosses. Amer. Nat. Vol. LI. Nov., 1917, and George F. Freeman, A mechanical expiation of progressive changes in the proportion of hard and soft wheat kernels. Journ. Amer. Soc. Agron. Vol. 10, No. 1 ) have been published. Others are in course of preparation. In the wheat breeding work 500 plots of hybrid wheats were grown at the Yuma station. These formed the basis of further selections for planting in the fall of 1917, at which time 600 head rows, 100 pedigree increase plots and 25 one-tenth-acre plots were l>lanted at the Yuma station. At the Mesa farm 10 one-fourth-acre and three one-half-acre plots were jilanted, for testing on a still larger scale, a number of promising pedigree races which had been previously grown in quantity sufticient for making milling and baking tests. These milling and baking tests were made by the milling department of the Kansas State Agricultural College and, include the determination of the following characters of the wheat : Weight per bushel ; percentage of flour, moisture, ash, aciditv, pro- tein and phosphorus ; and of the Hour, the moisture, ash, acidity,, protein, wet gluten, dry gluten, phosphorus ; and of the bread the following: Water, absorption, time of fermentation, maximum volume of dough, oven rise, weight and volume of loaf and color and texture of crumb. The results obtained during the past three years from a com- parative study of Arizona wheats, indicate that grain of excellent milling and baking quality can be raised on irrigated land in this state and that there are striking differences in the bread-making (|ualities of different varieties when grown under identical con- ditions. Plate I is introduced as an example of these facts. The k)af in the center was baked from a blend of hard wheat flours grown in Kansas. Such blended flours make a larger, lighter loaf than could be obtained from the flour of any one wheat alone. The loaf at the elft was from Arizona grown Early Baart wheat produced on the Agricultural Experiment Station at Yuma in 1915. It will be noted Arizona Agricultur-\l ExpkrimivXT Station 457 that this loaf is ahiiost equal to that arising from the blended fiours. The loaf at the left was produced from White Sonora wheat. This was also grown at the Yuma station in a plot adjacent to that on which the wheat giving the loaf at the right was grown. It is here introduced to show how strikingly the bread-making qualities of some varieties may differ, although grown under identical condi- tions. Realizing as early as 1899 that the product of the flour mills of the state could not long compete with flovtr imported from the hard wheat districts of the middle west and north, so long as they used locally grown White Sonora wheat, the Experiment Station began casting about for a higher grade wheat, which would yield well in Arizona. To this end a number of foreign wheats were imported and tested. As a result of these tests the best variety. Early Baart, was introduced to the farmers in 1902. During the interim before the Early Baart was widely distributed, the milling industry suffered greatly, to such an extent that several of the mills were compelled to close. Early Baart, however, pro^^ed so much superior to the old W^hite Sonora in quality that the remaining active mills are now urging that their constituent farmers grow no other than Early Baart wheat. The superiority of the Early Baart in milling and baking qualities is clearly exhibited in plates II and III. Plate II is from the crop harvested in the spring of 1915 and Plate III from that harvested in 1916. The wheats giving rise to these loaves were grow^n each year on adjacent plots and were given identical treatment as to culture and irrigation. In both plates, the loaf baked from Early Baart flour is placed at the center, with the Sonora loaf at the left. On the right in Plate III is shown a loaf from Arizona grown Turkey Red whea/. This is the stand- ard hard winter wheat of the middle j)lains region. Results for two years (1915 and 1916) indicate that for Arizona conditions at least the Early Baart is a better milling wheat. T.vnLE XII. — YIELDS, MILLING AND BAKING TESTS OF ARIZONA GROWN W H EATS Variety Year grown Yield per A. bu. Wt. per bu. lb. Volume of loaf Character of crumb Sonora 1915 « 1916 tt 51.7 43.3 43.2 34.3 39.1 49.5 43.2 62.3 61.5 60.0 57.5 63.5 61.5 62.8 1650 CC. 1690 " 1640 " 1375 " 1780 •■ 2(>35 •• 1675 '• Eine — licht Early Baart Turkey Red Alaska or Mummy Sonora Early Baart Turkey Red (( t* ti It Coarse — heAvy Fine — light it u 458 TwuxTv-KiGHTH Annual Report ■J. 5 "I o a: 3 re O r- Co ^ cd C K (1) G 01 ^ p bib ai c o ^3 < 0) 0 0 03 0 ^ -^ T-t Ti 03 rH (TJ a 0) m i> ^ c '^tM >. 3 0 ~ 0 ctf ;> 0 cS ;_ 0 oi J r. 0 U 1 t-H 0) -4-J ri fl. AuizoxA Ac;ktcultukal Experimkxt Station 459 4a\ TVVKNTY-J-IGHTII A.XNUAL REPORT OJsc 0) c i c C3 i-I 0; ^ ■*- cc - J- c rn c 0/ . C -M O o o . C c AR120XA AC.RICILTURAL EXPERIMENT STATION , 461 The comparative yield tests have not given tinally definite re- sults inasmuch as in 1915 the White Sonera gave the best yield, whereas, in 1916, the best yielder was Early Baart. Table XII gives a brief summary of the yields and milling and baking tests of these wheats for 1915 and 1916. At the right in I'latt- II is shown a loaf of bread produced from a plot of Mummy or Alaska wheat. The yield and loaf volume of this variety are shown in Table XII. Several years ago this wheat, under the name of Alaska wheat, was introduced into Arizona and the seed sold at a high price by parties who made wonderful claims for its yielding power and milling quality. These tests show that it is in reality a practically worthless sort under Arizona conditions, and they moreover emphasize the necessity and economy of having some competent and reliable authority (such as the State Exi)eri- ment Station) test all varieties of agricultural crops before the/ are widely sold or planted within the state. The results of several years tests at this station have shown the decided superiority of Early Baart as a milling wheat and that in yield it is at least not inferior to other sorts. Under these cir- cumstances the Experiment Station does not hesitate to recommend this variety where it is planned to grow a milling wheat. Thus a superior wheat, introduced about twelve years ago by the Experiment Station, has now almost completely replaced all other varieties as a milling wheat, and has not only gone a long wav toward saving the several hundred thousand dollars invested in milling machinery but has also held for the farmers a local mar- ket for one of their principal farm crops which otherwise was slip- ping away from them in the gradual death of the milling industry t)f the state. It is not claimed that the Early Baart is a perfect wheat and that it would be impossible to improve upon it. As a matter of fact, among the several hundred hybrid wheats produced by this department there are a number which appear very promising, and it may be possible that some of them will prove superior to the Early Baart. Until, however, they have been thoroughly tried by both yield and milling tests it would be unwise to substitute any tif them for a variety which has already established its value and reliability in the state. Geo. F. Freeman, Plant Breeder. W. E. Bryan, Asst. Plant Breeder. ANIMAL HUSBANDRY The year just closed has been one of unusual concern to Ari- zona stockmen. A cold winter and late spring: caused considerable losses among range animals in the northern and southern counties. Summer and fall range was unusually good in Coconino, Yavapai and parts of Mojave counties. The larger part of the range pro- ducing districts received little summer, and practically no fall rains, so that the year closed with ranges in bad condition, and Gila, Pinal, Yuma, Maricopa, Cochise and Pima counties were losing many animals. Over most of the range producing states the fall range was inferior, and this closed the demand for stockers and thin cows so that few animals were sold and prices ruled lower than they were since 1913. This left the ranges much overstocked ; feeds were scarce and high in price, so that losses have been unusually severe. Except for the high mortality among shorn sheep and y(jung lambs during the late spring sheepmen have had an unusually profitable year; ewes, lambs and wool almost doubled in value. Range was good in most of the sheep growing centers and no diffi- culty was encountered in marketing the surplus. The sheep and goat industries are on a sounder basis than ever before in the state and increases in the numbers of these animals can be expected if winter feed or range can be secured for them. In irrigated districts there has been a distinct tendency to liquidate dairy cows, hogs and horses owing to the high price of long staple cotton, forage and grains. Stockmen believe that there is more money in producing crops for market than marketing them through the live stock route. They lose sight of the important consideration that live stock must ultimately be depended upon to secure a market for most agricultural products, and it is certainly a mistake at this time to go out of the dairy and hog producing busi- ness in irrigated districts. Dry farmers are increasing their live stock holdings as a means of utilizing crops. Range stockmen are looking more and more to the production of feeds as an insurance against range shortage, and. for finishing sheep and cattle for market. They have purchased Arizona AGuicui/ruRAL Experiment Station 463 large acreages in both dry farming and irrigated districts and are nsing many silos to store the feed. INVESTIGATIONS Seven distinct lines have been followed in the investigations in animal husbandry during the past year. These were : 1. Sheep Breeding Experiments. 2. Marketing Arizona Wool. 3. Alfalfa Pasture for Hogs. 4. Feeding Dairy Cows. 5. Silage for Range Cattle. 6. Poultry Management. . 7. Systems of Live Stock Farming. SHEEP INVESTU'.ATIO.XS Further reductions have been made in the number of cross- bred sheep on the Salt River Valley Farm, and the policy has been to maintain the best sheep -in this flock and compare them with other breeds. An inventory of the sheep present July 1, 1917, is given in Table XIII. TABLE XIII. — INVENTORY OF SHEEP JULY 1, 1917 Breed Rams 1 yr. and over Lambs Ewes 1 yr. and over Lambs Hamnshire 2 2 1 5 2 3 8 19 14 7 14 46 6 Shronshire 2 Tunis 3 Cross-bred 27 Eleven Hampshire ewes and five lambs and one Shropshire ewe and a lamb were added to the flock during the year. They are a very desirable addition to the equipment of the department. IVool Production: The sheep were shorn on March 5th and 6th. 1917, Yielding a total of 526.8 pounds of wool and averaged 6.35 pounds per head. Table XIV gives the average yield of wool from the registered sheep and the main crosses. T\1:LE XIV. — AVKK.M.K WOOL CLir ACCORUI.VG TO BREEDING, 1917 Hampshire 5.12 lbs. Shropshire 5.67 lbs. Tunis 6.22 lbs. Hampshire crosses 6.60 lbs. Shropshire crosses 6.71 lbs. 464 TwDNTv-KiciiTii Annual Report Breeding Records, igi6-ij: In the fall of 1916 the cross-bred ewes were bred to the cross-bred bucks Nos. 504 and 549. All pure- bred ewes were mated with registered rams of the same breed. A normal lamb crop was secured and those were inspected carefully and notes taken on July 1, 1917. The lambs sired by the cross-bred buck No. 504 and out of cross-bred ewes were of medium size, blocky, uniform and of good quality. About half of the lambs had black faces and legs, while tlie remainder of them Aaried in color from dark brown to mottled or light brown. The wool fr(»m these lambs was short but hno, soft and dense, and not more than lO'/r of them had inferior w^jol. About half of the lambs sired by buck No. 549 had light colored faces and not more than 25 ^^ had dark points. Many were ahnost white in color, or light brown, and others mottled. These lambs were long in the legs, bodies and necks. They had droojiing rumps and were light in the leg of mutton. Fully 60*^,- of them were so inferior that they had to be culled out. The wool varied greath- In fineness, density and purity. Summing up the qualities of the two rams as shown in tlieir offspring, the lambs from ram No. 549 were longer, narrower and. more rangy than those from ram No. 504. Thev were also less vigorous and had coarser, less dense wool, containing more kemp. The lambs from No. 504 were much more uniform than those from the other ram and there is no doubt that from the standpoint of power to transmit dark points and gO(^d wool he greatly excels the other ram. Some criticism, however, could be made of the small size of the lambs coming from this ram, but the uniformit^' and desirability of his lambs in other respects warrant his use another year. Buck 549 was discarded. MARKl'lINi; \\o:)L Two lots of wool were marketed to ascertain the dift'ereuce between local and outside ])rices. One lot consisting of 743 pounds of wool was shipped from the vSalt River \'alley Farm and the other lot of 78 pounds from Tucson. These were consigned to commis- sion agents in Boston and Chicago with a request that the w^jol be graded carefully and each grade sold on its merits. The higliest prices obtainable at local ]")oints were 33 cents for the vSalt Ri\-er \'alley wool and 21 cents for the Tucson wool. The commission firm at Bostoti secured 44 cents for the Tunis wool, and 62 cents for tlie cross-bred wool. The Chicaijo asfent sold .\kiz(i\.\ .\(;kktltur.\l ExpKrimK.xt Station- 465 lit 45 cents for the Tunis wool, 50 cents for the cross-bred, and 60 cents for the reg-istered llami)shire and Shropshire wool. Roth agents rei)orted that the Tunis wool was highly undesirable on ac- count of the large amount of brown hairs which it contained. These brown hairs lo not take stain properly and are not suitable to make white yarn. The Boston market accejited the cross-bred w<>u\ as liighlv desirable, but discounted the Tunis wool 18 cents a pound below ])rices for good grades. The Chicago agents reported a dis- count of 10 cents a pound in the cross-bred and 15 cents a jtound in the Tunis wa^ol below that of Hampshire and Shropshire quality. The increase in weight of wool between .\rizona and eastern points was quite pronounced. No rain had fallen in Arizona within twenty days from the time of shipment, although the precipitation on that day was .20 inches with a trace the day before. Table XV shows the relationship of the Arizona weights and after storage in Boston until November 10, 1917. TABLE XV. — WEIGHTS OF WOOL AT ARIZONA AND BOSTON, 1917 Name No. of sacks Net Ariz, weight pounds Increase in weights Price Value of lbs. % per lb. increase Tunis Cross-breed . McElvain . . . Longmore . . . 1 2 2 I 6 87 358 219 79 743 5 19 13 00 ^7 5.8 5.3 5.9 0.0 — ■ $ .44 .62 .60 .00 $ 2.20 11.78 7.80 .00 Total $21.7'^ The wool increased 37 pounds on an initial weight of 713 pounds, which is approximately 5% of an increase in weight of the wool. The value in this increase in the weight of the wool was $21.78. or 62% of the cost of marketing. This amounted to more than the freight on the wool from Arizona to Boston. Other figures secured from private shipments of wool indicate that somewhat larger increases may be secured. It is highly interesting to note that there is much less dis- crimination between good and inferior wool in Arizona than at the large markets. This suggests that local dealers believe in buying wool sufficiently low to yield a profiit on almost any grade of wool which may be purchased. The total expense of marketing 74,^ pounds of wool was $34.90. which is approximately 4.7 cents a pound. When the increase in the weight of the wool is taken into consideration lJ-4 cent a ]iound would be sufficient to send the wool lo eastern markets. In one shii-nieiit of wool it was found that the 466 TvviCNTv-KiGHTii Annual Report net receipts from the commissiuu agent was 142 yc greater than tlie highest local quotation. This suggests that persons producing as small quantities of wool as 50 pounds would profit by consigning their wool to a warehouse or commission firm. ALFALFA PASTURE FOR HOGS The modern method of feeding hogs in Arizona is to maintain them on good alfalfa pasture, and feed liberally on grains. Prelimi- nary tests were conducted to ascertain the elYect of feeding young pigs t)n alfalfa pasture alone and to learn the results of adding alfalfa pasture to an otherwise well balanced ration. Alfalfa Pasture for Young Pigs: Two pigs 97 days old were placed on a plot of alfalfa pasture and maintained there without additional feed for eight weeks. During the first four weeks these pigs lost two and one pounds, respectively, and the next four weeks they gained eight pounds each. Oyer the entire eight weeks the pigs on alfalfa pasture gained only six and seven pounds, respect- ively, while the litter mates fed on ordinary rations made a gain of 40 pounds each. The results of this test prove that gains are extremely low with young pigs maintained on alfalfa pasture which is too coarse and bulky for them. After the pigs become older they will make slow but steady gains on alfalfa pasture alone. Balanced Rations and Alfalfa Pasture I's. Balanced Rations in a Dry Lot: Ten registered Duroc-Jersey pigs were divided into two lots of five each. Both of these groups were fed rolled barley and skim milk, but Lot 1 was fed in a dry lot and Lot 2 was given a small amount of alfalfa pasture. Each lot Avas given two pounds of rolled barley and six pounds of skim milk ])er 100 pounds live Aveight. The experiment covered a period of 12 weeks and the animals were weighed once a week during this time. As the ex- periment advanced the amount of barley was increased to three pounds per 100 pounds live weight and the skim milk continued at the same rate. The lot consuming alfalfa pasture made more rapid gains, but consumed 80.5 pounds more rolled barley and 108 pounds more milk. During the entire experiment the pigs in Lot 2 made more economical gains from the grain and skim milk consumed. This difference was especially pronounced at the beginning of the ex- periment, but towards the close there was little difference between the two lots in the amount of food required to produce 100 pounds of gain. No doubt the larger and fatter hogs made less efficient use Akizox.\ agricultural Experiment St.vtiox 467 of the feed as they became more mature. Table X\T gives the average gain of the ])igs according to four-week periods. T.M'.Lli XVI. — GAIXS OF PIGS .\CCORDING TO FOUR WLKK PERIODS Lot 1 Lot 2 Period Total gain l)ound.s Average gain per pig pounds Total gafn pounds Average gain per pig pounds 1st 4 week.s 2n(i 4 weeks 3rcl 4 weeks Entire three periods 81 125 167 373 16.20 25.00 33.40 24.87 105 145 183 433 21.00 29.00 36.60 28.87 In every case the pigs in Lot 1 gained more slowly than those of similar breeding and individuality which were given the same food but allowed alfalfa pasture. It was only in the third period that the pigs in Lot 1 gained as much as one pound per head daily, but the animals in Lot 2 gained over one pound a day. except dur- ing the first four weeks. The animals receiving alfalfa gained 60 pounds more than those not allowed this food. The animals in Lot 1 were distinctly unfinished in appearance, and much inferior to those receiving alfalfa pasture as judged from market and breeding standpoints. They averaged 12 pounds less, in weight and there was a greater difi'erence in attractiveness and in finisli than the weight would indicate. An average of 485 pounds of pigs were maintained oti about, one-eighth acre of alfalfa pasture. This is fully 2,000 pounds of pigs per acre at the outset and 5,600 at the close of the experiment. An acre of good alfalfa pasture will carry at least twenty hogs averag- ing 100, or 10 averaging 200 pounds. From this small plot of alfalfa and 80.5 pounds more rolled barley and 108 ]:»ounds more skim milk the hogs made 60 pounds more gain in twelve weeks than those in the dry lot. At 15 cents a pound the increased weight on the hogs would mean a yield of $9.00 for the pasture and the addi- tional feed for the pericxl. Deducting $2.95 for the value of the additional rolled barley and skim milk, this would mean $6 05 for one-eighth acre of pasture or $48.40 for one acre in three months. This places a high feeding value on the alfalfa pasture. After the close of the experiment the animals in the two lots were placed together and those that had l)een allowed alfalfa jiasture made more rapid gains and appeared to be more vigorous than those on the drv lot. 468 TwHNT^-KicjiTii Annual Report ALFALFA HAV vs. ALFALFA H W AND SILAtJF FOR DAIRY COWS During the spring of 1917 an experiment was conducted to de- termine the vahie of corn silage as a supplement for alfalfa hay when fed to dairy cows. Corn silage can be produced to good advantage on Arizona farms, and dairymen are beginning to use it quite extensively for balancing the highly nitrogenous ration sup- plied by alfalfa. Many dairymen want information regarding the use of silos, and it is highly important that some preliminary v/ork be done to ascertain the desirability of adding silage to alfalfa hay. Seven cows were used for this test and these were divided into two groups, three in one and four in the other. Since the groups could not be evenly balanced in number, quantity of milk produced, and similarity in lactation period the feeds were alternated so that each lot was given each ration the same length of time. The cows were maintained in separate corrals and an accurate (|uantity of hay given each lot. The corn silage was fed individually at the time of milking. An interval of ten days was allowed between each period in order to accustom the cows to a change in ration. During the first period of 21 days Lot 1 was fed a ration of 20 ])ounds of alfalfa hay and 35 pounds of corn silage, and Lot 2 was given 30 pounds of alfalfa hay. During the second period the rations were reversed. Table XVII gives the result oi the experiment. TABLE XVIL — AVERAGE DAILY YIELD AND COST OF RATION OF COWS FED ALFALFA HAY COMPARED WITH ALFALFA HAY AND CORN SILAGE Average daily yield Cost of ration Ration Milk lbs. Pat lbs. per head daily cent.s Ration 1 Alfalfa hay 20 lbs Corn silage 35 lbs Ration 2 Alfalfa hay 30 lbs 24.27 24.72 .881 .846 • 30 30 The amount of milk and butter fat produced was practically the same for both rations. Where alfalfa is priced at $20 and corn silage at $6 per ton, the cost of the rations per day was the same for each lot. The experiment shows that 35 pounds of corn silage may replace 10 pounds of alfalfa hay in the ration. Most of the cows lost weight during the test period, but it was found that 30 pounds of alfalfa hay tnaintained the live weight more uniformly than the ration consisting of 20 pounds of alfalfa hay and 35 pounds of silage. The silage was dry and inferior in quality and it is be- lieved that more favorable results would have been secured from Arizona AciKicuLTUKAL Expkrimunt Station 460 both the standpoint of milk production and maintaining body weight with an equal quantity of good silage. SI LACE FOR RANGE CATTLE The crops of corn and grain sorghums secured at the Cochise and Prescott Dry Farms were placed in silos and used for studying the suitability of silage to tide cattle over short range. In Cochise County the range was unusually short and backward during the year 1917, and the heavy covering of snow in Yavapai County pro- duced short range, causing many animals to die from starvation. Cochise Dry farm: Fifteen cattle were fed silage and dry pas- ture to ascertain the economy of using dry farm feeds for range cattle. The animals were a mixed lot, consisting of three Hereford steers, nine months old, two Hereford heifers, two years old, one Holstein heifer, two years, one Hereford Bull, two years, and six cows of mixed breeding, ranging in age from two to ten years, ^rhere were five cows with calves at the beginning of the experi- ment, and another calf was born before the experiment closed. The animals averaged 564.3 pounds at the beginning of the test and after being fed an average of 98 days weighed 646.4 pounds. They con- sumed about 55.4 pounds of silage jjer day and gained from 1 to 125 pounds per head. The entire lot of 15 (omitting the calves) gained 1231 pounds, or an average of 82.1 pounds per head. Prescott Dry Farm: In February, 1917, fourteen grade Here- fords were selected to study the efifect of feeding silage alone over a period of six weeks. Among the animals were seven cows so thin that a conservative stockman estimated about four of them would die before spring if left on the range. The animals were given all the silage they would consume without waste. The aim was to feed them well so that they would be in good condition rather than to learn how little silage would carry them over the winter. The animals ate about fourteen tons of silage or one ton each in six weeks. This would amount to 47.6 pounds consumed per head daily. All the cattle thrived on the silage and undoubtedly made good gains. They were strong at the close of the experiment and withstood shipping a considerable distance to spring range. During the summer they proved to be good rustlers and gave every indication of having completely recovered. The results of the two tests give conclusive proof that silage is a good feed for cattle when the range is inferior. The succulent and nutritive qualities of the silage not only keep the animals alive, but it gives weak, hungry cows a new strength to hunt for food. 470 TwiiNTV-KlGHTH ANNUAL REPORT The cows and young stock did unusually well after being turned out on the range and all except those with calves were much fatter and more vigorous than similar animals left on the range. Since there are large areas in dry farming and overflow dis- tricts suitable for growing crops for silage these experiments sug- gest that stockmen should put forth every possible effort to secure good land and raise crops which may be fed the animals during short range. ^ POULTRY In the years 1916-17 four breeds of chickens were continued from the previous year. These were the S. C. W. Leghorns. S. C. R. I. Reds, W. Plymouth Rocks, and Black Langshans. They were used chiefly for class purposes, with an effort being made in the spring of 1917 to rear enough new stock to make the ])lant self- supporting. The plan for 1917-18 includes the moving of part of the poultry plant to a new location just south of the present site in order to make room for the new observatory. A pen of ten hens with pullet rec(jrds averaging 230 eggs will be added to the present stock of Leghorns. From this pen it is planned to develop a flock of Leghorns of high a^g production, gradually discarding all hens that have records less than 150 eggs per vear. ^ ^ , ' " INSTRUCTION AND KXECUTIVK WORK Much time has been devoted to the general work of the depart- ment such as supervision of the live stock, planning new equipment, ])urchasing new animals, judging live stock at fairs, addressing meetings, correspondence, and personal conferences with stockmen. The number of students taking work in animal husbandry has increased over past years. Fifty articles have been ]niblished in technical journals and local periodicals regarding live stock. The department has had supervision of the official testing of the registered cows of various pure bred associations. A number of very creditable seven day official records have been secured with Holstein Friesian cows owaied by prominent breeders in the State. Several Jersey as well as Holstein cows have been under semi- official tests for a year, but not many have completed their records. The cow, Josephine Arizona Maid 164449, gave 13,414.9 pounds of milk, 406.7 pounds of butter fat and 508.38 pounds of butter in .365 days. This cow is owned by the University and she is the first one tested in the State to be accepted by any pure bred association for the vear-long test. Arizona .ViKicuLTUKAL ExpurimKnt Station 471 The Ihilstcin Friesian herd lias been increased very materially by the piu'chase of a lierd sire, live cows, five heifers and two calves. These animals rei)laced some of the jrrade cows which have been retained dnring the past five years. Table XVI 11 gives the vield of cows in the herd dnrinc: the ])ast year. 'lAliLK will. VIKLDS Ol' DAIKV COW S AT TlIIv UNIVERSITY FARM, 1916-17 NmiK! of cow Josephine Arizona Maid. Miss Columbia ("jirl Childebcrte Princess of Clicwawljcek Gipsy Draconis Blanco Mollie Exception II Pedro *Sheppardcss *Xettie *IMissonri .Averajjc for lierd Breed Holstein Friesian Jersey (^,ra l(il>tein Ayrshire Jersey drade 1 lolstein £ tic I c "=££ "*" I Ylo> >>^ SS2 76 444 0 299 87 272 100 363 34 287 36 374 42 312 65 311 49 275 105 409 Si 277 6S 233 59.7 321.3 Yield in lbs. Milk Butter- fat 14,447.4 432.2 3,342.3 231.8 4.885.1 291.0 6.721.2 358.9 5,797.7 281.2 7,742.7 274.8 9.350.3 344.0 6,921.0 261.9 7,242.9 382.4 13,371.9 439.3 9,770.6 410.2 6,554.5 273.S 8,012.3 331.8 ^_2 2.99 6.93 6.63 5.34 4.85 3.55 3.67 3.78 5.28 3.19 4.19 4.16 4.14 *Sold before finisliing- their milking period. •The Duroc-Jersey herd of hogs has been increased by the addition of two sows and a boar. It has been the policy of the de- partment to keep nothing- but registered animals of sui)erior qnal- itv. To this end, all of the grade cows have been discarded. Owing to the limited amount of land available for raising crops it is thought best to select a fcAv of the more important breeds and con- fine our efforts to them rather than to maintain a large number of breeds. Holstein Friesian, Jersey and Hereford cattle; Rambouil- let. Hampshire and Shro]:»shire sheep, and Duroc-Jersey and Poland-China pigs should be the first breeds to be developed. It is hoped that during the next year a good foundation flock of Rambouillet sheep and herd of Poland-China pigs may .be se- cured. Another urgent necessity is the purchase of two Jersey females. With the present increase in the Holstein cattle and Duroc-Jerse}' hogs moreAmiform animals are availal^le for investi- gation and instructir)n. R. H. \\'ILLI.\.MS. . Inimal Hnsbandumn. W. S. Cunnin(;ham, Assistant .Iniiiial 1 1 ushandman. ENTOMOLOGY During the past season the writer has considered that grass- hopper control was the most important single problem which could be taken up as a matter of demonstration and direct aid in the con- servation of important crops. The matter of grasshopper control has been disposed of for the most part as an experimental project by numerous investigations which have been conducted in various parts of the country during the i)ast few years. However, there Is a diversity in the details of the recommendations which have been published which show^ that we still lack important information In certain respects concerning the subject. In connection with demon- stration work against grasshoppers in the Salt River Valley during the past season problems were presented which lead to a series of observations and tests which are of considerable local importance. The differential* grasshopper {Melanoplits diftercntialis), the most destructive species in Arizona, is the one which was the subject of the investigation. The formula for poisoned bait which is now most generally recommended by entomologists consists in a mixture of 25 pounds of bran, 2 quarts of molasses, 1 pound of Paris green, 3 to 6 finely chopped lemons or oranges and water to make a crumbly mash. The more important experiments conducted by the writer concern the matter of modifications of this formula with the view to reduc- ing its cost and possibly increasing its effectiveness. Miscellaneous observations were made in connection with these experiments. In many sections of southern Arizona cull canteloupes can be obtained by farmers without expense and the experiments referred to above have shown that canteloupe can be substituted for the lemons in the usual grasshopper bait formula. One pound of finely ground. canteloupe may be substituted for six lemons. The experi- ments have further shown that with the differential grasshopper in the adult stage the molasses may be omitted without interfering with the results, also that in the place of 25 i)ounds of bran a half and half mixture of bran and sawdust may be substituted. These changes in the grasshopper bait formula represent a substantial decrease in the cost of grasshojiper bait. A long series of experi- ments was first conducted on a small scale and the baits made with the substitutions noted were afterward tried out on tracts of land Arizona AgricuIvTural Experiment Station 473 varvino- fn)ni five ti) fifteen acres. Additional field tests will be necessary before the new formulae can be recommended for use against other species of grasshoppers in Arizona or against the immature stages of the differential grasshopper. Miscellaneous observations made in connection with these ex- ])eriments with poisoned baits concern the time of day when the grasshoppers feed most actively, the distance grasshoppers travel after eating a fatal dose of the bait and the amount of alfalfa which adult differential grasshoppers consume per day. The observations in regard to the time of day when the grasshoppers eat most ac- tively were not conclusive, but from the records it appears that there is no advantage in spreading the bait late in the afternoon or very early in the morning, as has been generally supposed. Out of 3382 observations made between 3 and 6:45 P. M. it was found that 40.4 percent of the feeding records were between 3 and 3 :45, 30.3 percent between 4 and 4:45, 17.6 percent between 5 and 5:45 and 9.5 percent between 6 and 6:45. These observations will be continued in order that the question in regard to the time of day when the bait can best be scattered may be definitely determined. In order to appreciate fully the effects of poisoned baits it is neces- sar^■ to know how far the grasshoppers may travel after eating a fatal dose of the poison. The observations made show that poisoned grasshoppers very rarely traveled as far as 70 yards and that under ordinary conditions few traveled further than 25 yards from the place where a fatal dose of the poison is eaten. '^rhe observations made in regard to the amount of alfalfa which grasshoppers may consume have been found to be very effective in demonstration work. The figures obtained refer to the differential grasshopper. It was found that one adult grass- hopper per square yard may destroy the equivalent of three pounds of alfalfa hay per acre per day. In a forty-acre field a moderate infestation averaging 16 2-3 grasshoppers per square yard may destroy the equivalent of one ton of alfalfa hay per day. Grass- hopper infestations have frequently been noted averaging between 25 and 50 grasshoppers per square yard. It is obvious to a grower to whom these calculations are presented that the expense of poi- soning with one of the poisoned baits is exceedingly small in pro- jwrtion to the damage done by the insects. A. W. MORRILI., Consulting Bntomologist. CHEMISTRY During the year the chemists have accomplished the usu.il amount of analytical work, mostly of soils and irrigating water, for the farmers of the State. Research work has been restricted to the study of alkali, both in the field and in the laboratory by means of the auxograph. In this connection a large number of graphs have been made showing the influence of alkali and of soil solutions on the swelling of colloids. During the summer months we were forced to discontinue this line of work because of the disturbing efliect of high temperatures. The annual analyses of the Salton Sea Water, made in co-operation with the Carnegie Desert Laboratory, and incorporated in the annual report of this department for several, years past, have been discontinued, because it was believed that the chief facts to be learned from the work had been discovered. Only, occasional analyses of the water will be made as the sea continues to dry up. Much work was done on perfecting apparatus for pasteurizing and ripening dates, requiring the services of the assist- ant chemist at the Tempe Date Orchard for several weeks. In- struction and laboratory practice in soils have been given in the, College of Agriculture, and much time has been devoted by the chemist to matters of curriculum and registration of agricultural students. THE TEMPE DRAINAGE DITCH In the Twenty-seventh Annual Report a series of six monthly, analyses of the water from the new Tempe Drainage Ditch wus tabulated. Eleven additional analyses are now available and urc presented in the following table, together with those previously reported : ArIZOX.V Ac.KICULTURAL EXPRRIMKXT Sl'.MIOX 475 TAHLli XIX. MOXTHLY VARIATION IX COMPOSI'IIO.X OF W.VTKR KKO.M THE TEMl'K DRAIXAGIC DITCH, PARTS PER 100,000 — ( 1!V C. X. C.\TLIX) Date 1916 June 25 Julv 13 Sept. 10 Oct. 10 Nov. 10 Dec. 8 1917 Jan. 7 Feb. 10 Mar. 9 Apr. 10 May 10 Jnne 10 July 19 Sept. 15 Oct. 14 Nov. 10 Dec. 10 Total Solids Chlo- rides as NaCl Hardnes.s (perma- nent) CaSO, Q) O CO- 1665.2 1170 135^.0 994 599.4 432 418.0 303 3 40.4 220 312.6 228 322.4 227 312.0 216 241.0 163 308.0 222 298.6 217 309.2 209 351.0 228 423.6 298 225.2 145 303.6 205 292.4 168 107.4 27.2 hJ) 7.6 5.4 6.5 3.2 ' 7.6 7.6 10.8 6.5 32.6 Neutral 4.9 ri 67.2 66.4 60.3 64.0 55.5 64.0 58.5 66.8 62.7 65.2 66.0 61.5 65.6 131.2 122.1 Alka- linity Na^COi SO4 3.4 11.87 172.53 64.76 30.49 33.78 Str. CaO MgO 97.64 14.2 12.6 14.6 65.2 25.2 17.57 15.75 Mod. Str. Str. Mod. Mod. Str.lMod. Str, Slight Mod. Str. Mod. Mod. Str. Mod. Mod. Mod. Str. Mod. SH«ht str. — Strong-. Mod. — Moderate. Mod. Str. — Moderatelj- strong. The ditch was completed early in 1917. thus the water for some, months has not been affected in composition by the draina«^e of new areas. All samples have been taken from near the outlet end of the ditch. The season has been very dry and, consequently, the composition has been changed but little by the runoff' of meteoric water diluting the seepage ; nevertheless, great fluctuations in com- position are noticeable. March 9 the water, which had hitherto been hard, was alkaline, containing 3.4 parts per 100,000 of lilack alkali ; but the following month, April 10, it was again found to be as hard as it had been the previous November. The analysis made in February seems to indicate that the permanent hardness of the water was decreasing at that time. During the summer months the hardness remained fairly constant, but increased three or four- fold in September, then became neutral in October and again strongly black alkaline in December, which is the last analvsis available. The total solids dissolved in the water and the chlorides show similar fluctuations. September 15 both total solids and chloride reached a maximum, but dropped abruptly to about one-half that amount in October. This period of high solids and chlorides was 476 TVVI^NTV-EIGHTH ANNUAL REPORT accompanied by very high permanent hardness. In November and December the temporary hardness ("lime") increased to double the average for the other months of the year, which had been nearly uniform. Fluctuations during 1916, when the total solids were decreas- ing rapidly, were explained, apparently, by the opening of new drainage areas as the work on the ditch progressed. The present fluctuations are less easily explained but are probably due to changes in the amount of seepage from various areas according to the amount of irrigation, and also to overflow reaching the ditch which would tend to dilute the usual seepage flow. At no time has the drainage water been entirely satisfactory for irrigating purposes on account of its high salt content. At times when the salt is ex- cessive, as was the case in September, the water should not be applied to agricultural lands. The high black alkalinity in Decem- ber would be dangerous if long continued, but the usual gypsum content of the water would serve to neutralize the occasional black alkaline flows. It is possible that a correlation between the dis- tricts receiving heavy irrigation and the character of the drainage ditch water could be worked out for the purpose of avoiding the use of excessively saline seepage water on the Indian Reservation lands below, that are being irrigated with this water. A simple volu- metric test for chlorides is available and should be applied at fre- quent intervals by some person in the immediate vicinity. Waters above the average in salinity should be allowed to waste. NATIVE FERTILIZER MATERIALS The prevailing high prices of fertilizer materials, especially of nitrogen and potassium, has stimulated the search for these sub- stances in the State. The deposits of bat guano have been drawn upon quite heavily for exportation. The discovery of nitrate of soda or Chili saltpetre in some of the rocks of the State has awak- ened much interest. The cliemist visited one of these deposits near San Simon and secured samples for analysis. The rock, whicti is a rhyolitic tufa, is often covered with incrustations one-half inch thick, more or less, of nearly pure nitre where overhanging ledges protect it from the weather. The rock itself shows a few tenths percent of nitrate of soda, but occasionally very thin seams of the nearly pure salt occur. A tunnel driven ten feet into the ledge did not develop richer material. Recently a sample of similarly in- crusted rock has been sent in from another part of the State, but Akizu.\.\ .\.c;RiCL-i;ruK.\L ExperimivNT Station 4 / / its Di-igin has nut been learned. A soil from the Casa Grande dis- trict sent in to be tested for alkali showed nearly ten percent of nitrate of soda. The sample was probably a surface incrustation and did not represent the soil to any appreciable depth. This mate- rial could be used to advantage as a fertilizer on lands in the neigh- borhood that are poorly supplied with nitrogen. Several samples of saline materials and water from a barren oil well have been submitted to be tested for potash. In every case qualitative tests showed so little potassium that quantitative deter- iiiiniations were nt)t made. Mesquite and brush ashes, and ashes irom incinerators at the military camps have caused some public interest as possible sources of fertilizer. While these materials will seldom bear transportation charges to the fertilizer works, they of- ten can be used locally with profit. Caution should be exercised, h.owever, not to a])ply wood ashes to soils that tend to be black alkaline. UNUSUAL FEEDING STUFFS In co-operation with other departments several analyses of unusual feeding stuffs have been made. The results are shown in the following table : TABL^ XX. — COMPOSITION OF UNUSUAL ARIZONA FEEDING STUFFS Ether Feeding stuff Water Ash Crude protein Crude fiber extract (fat) Carbo- hydirates Yucca No. 1 72.1 1.55 2.09 4.50 0.43 19.33 Yucca No. 2 63.5 3.34 1.12 7.15 0.34 24.55 Sword beans 9.14 4.05 27.05 9.34 4.38 45.59 Alfalfa hay No. 1.... 6.73 8.42 16.21 29.52 2.61 36.51 " No, 2.... 4.53 8.42 14.89 29.86 2.33 39.97 Alfalfa straw, Mesa. . 3.46 8.26 8.95 41.46 1.87 36.00 " Yuma.. 4.79 5.01 6.44 49.48 1.13 33.15 Tepary bean hay No. 1 10.22 13.29 19.95 17.71 2.94 35.89 " No. 2 0.80 13.70 21.54 17.61 3.04 34.31 Sorghum refuse 9.38 4.57 2.62 32.98 1.39 49.06 Milo heads ground No. 1 6.19 4.67 8.99 7.61 3.30 69.21 Milo heads ground No. 2 8.55 4.13 11.46 6.77 3.11 65.98 Milo heads chopped , No. 1 8.23 4.07 11.63 6.83 2.96 66.28 Milo heads chopped No. 2 8.66 4.76 9.09 7.60 3.02 66.87 Bran, Phoenix Mills. . 7.94 4.98 16.65 6.82 4.63 58.98 " Minnesota Red 15.19 " Tucson Mills... 18.50 Cotton stalk hurds... 9.06 Shallu whole crain. . . 10.3? 478 Twi-x TV-EIGHT II Annual Rkport Yucca (Yucca data) No. 1 was young growth from w^iich the leaves had been removed, leaving only the leaf bases; No. 2 was somewhat older material. Sample No. 1 contained .19 percent of saponin in the fresh material, and Nd. 2 contained .21 percent, determined by precipitation with baryta water. No injurious ef- fects were observed when this material was fed ad libitum. Sword beans {Caiia^vlia cusifonuis) were grown and used for feed in Salt River Valley. They are said to yield well. Care should be used in feeding these beans, since they are sometimes poisonous. The alfalfa straws are produced in threshing ripe alfalfa for seed. They are much higher in fiber and lower in protein than the alfalfa hays which are given for comparison. Alfalfa hay No. 1 was grown in Salt River \'alley ; alfalfa hay No. 2 was grown it Yuma. Sorghum refuse was the residue after the cane had been crushed for syrup. Cotton stalks hurds were produced by crushing the stalks U> remove fiber for commercial purposes. The rather high protein is due to the removal of the fiber and to the seed that remained in unopened bolls. M I SCKLLANROUS ANALYSES On two occasions, when large numbers of livestock have died without apparent cause, the chemists have examined material for poisonous substances. A number of hogs, near Yuma, died in a field of Sudan grass, giving cause to suspicion poisoning by hydro- cyanic (prussic) acid, as is known to happen sometimes with drought-stricken sorghums. The animal materials were badly de- composed when received, but samples of the grass were sent to the laboratory with the roots balled in damp soil when taken up. No trace of hydrocyanic acid could be discovered in this grass. 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EVAPORATION TEMPERATURE Inches per day Degrees Fahrenheit MWAN WIND VELOCITY Mi.ies per hour 484 Twenty-e;ighth Annual Report nite policy of building farmsteads on the margins of the bottom- land should be adopted and all newcomers should be warned against building residences on ground subject to injury by river floods. It is possible that better river control by reservoirs on the Gila and its tributaries will reduce the menace in the future and levee protection will be possible to i limited extent. WELL DRILLING AND DEVELOPMENT Considerable time has been spent during the past year accumu- lating data on the drilling and perforating of wells and more par- ticularly on the development of the wells after perforating. This has been done with a view to early publication. EVAPORATION AND DUTY OF WATER For several years this department lias desired to undertake special investigations to study the relationship between the evapo- ration-rate and the duty of water. Although evaporation records are common and have been kept at various times in many places, yet the mass of data thus accumulated is almost worthless for com- parative purposes, because of the absence of standardization in equipment and method, and because as a rule no contemporary observations have been made of other climatic factors. Clearly, it was the province of the United States Weather Bureau to control such standardization, and in 1915, as soon as the Bureau had made, tentative plans for a standard evaporation pan, this office had sev- eral of them built. Later, when Congress made appropriation for twenty-five Class A evaporation stations, three of them were ob- tained for Arizona under cooperative arrangement. This station selected the sites and furnished the pans and standard enclosures. The Weather Bureau furnished hook gages, rain gages, and maxi- mum and minimum thermometers. The observers are paid by this station. The purpose being to test the hypothesis that water re<|uire- ments of plants are proportional to the evaporation-rates, three locations were chosen widely separated in climatic conditions. They are Yuma, the Salt River Valley, and near Willcox. The altitudes above sea level are 127 feet, 1225 feet, and 4200 feet, respectively. Approximately similar soil conditions were ^ound in tb.c three places, and in each place the evaporation pan and other instruments Arizona Agricui^turai. Experiment Station 485 were installed in the center of an alfalfa field. The duty of water for alfalfa is to be obtained. Fuller descriptions will be given in a separate publication, but the general results of the first year's observations are given herein in P'ig. 13. The temperature, the wind movement in miles per hour, and the evaporation in inches of water, in ten-day periods, are shown by graphs. A close agreement between the temperature and the evapora- tion graphs is very apparent for all three locations, but a careful examination reveals that the agreement is modified by the wind movement. Thus, the decreasing wind movement near Willcox in May and June prevented so rapid an increase of evai)oration as in March and April. The apparently erratic curve for Yuma in the summer months is due to the raising of a seed crop. At Yuma an:l at Willcox. in August, the wind movement was nearly equal and the difference in evaporation-rate appears to be due to difference in temperature. Reduced to lowest terms, the evaporation-rate depends upon temperature and the vapor pressure directly at the water surface. The first of these two factors is expressed here by the daily maxi- mum temperature instead of by the daily mean temperature, which is commonly used. The second factor depends upon the relative humidity in the vicinity, and the air pressure, in addition to the wind movement. Air pressure varies mainly with altitude, and the extent and direction of this variation has been much debated. The high evaporation-rate near Willcox is attributable in the main to the rapid wind movement, but may be due in part to the fact that the evaporation station near Willcox is in an isolated alfalfa field surrounded by semi-desert conditions, while at Yuma and Mesa the alfalfa fields are but parts of great irrigated valleys. Willcox lies on the western edge of a region which some investigators have as- serted to have the highest evaporation-rate for the United States. The importance of these investigations to agriculture is appre- ciated when one recalls that the loss of water by transpiratic^i from a well-develo])ed field of alfalfa is greater than the evaporation loss from an open water surface. The average annual loss from a well-irrigated alfalfa field cannot differ very greatly from that of a standard evaporation pan i)laced within the field. Farmers in the Sulphur Spring Valley have added incentive to ])lant windbreaks, to cultivate after irrigating, and to raise crops having low water requirements. 486 TVVKNTY-EIGHTH ANNUAL REPORT MACHINE-MADE CEMENT PIPE On account of the great importance of water economy in Ari- zona this Station has taken a lively interest in the manufacture of cement pipe and its use for irrigation pipe lines. In 1907 the Sta- tion published a bulletin on the subject and has constantly advo- cated the use of cement pipe for irrigating streams of moderate size requiring pipe up to 24 or possibly 30 inches in diameter. For farms that are under pump irrigation, pipe sizes from 8 to 20 inches in diameter are required commonly. During the last few years pipe machines have been developed for making cement drain tile in the Middle West, and during the past year these machines have been modified so as to make irriga- tion pipe. The opportunity presented itself to this department to bring one of these machines to Pima County and to study machine- made pipe and pipe-making. The results of these studies have been prepared as a bulletin and will be published in the near future. The general conclusions of the study are that pipe-making by machinery is entirely practical, that the pipe is much superior in quality to hand-made cement pipe and that the cost is less. The field for a new industry is open and inviting and pipe factories should be built and equipped at a half dozen places in central and southern Arizona. The ultimate result will be greater water econ- omy, and an extension of the irrigated area. For the larger laterals and main canals cement lining is the best method of improvement. Careful estimates show that by lin- ing the canals of the Salt River Valley enough water will be saved to permit an increase of 25 percent in the project area. EXPERIMENT STATION PUMPING PLANTS During the expansion of the Experiment Station work it has been necessary to develop many pumping plants, both for outlying stations and for the campus and the University Farm. A summary <:i these plants with general comparative data is of interest and is shown in Table XXI. In a semi-arid region such as Arizona water supplies are of primary importance. The Yuma and Prescott plants are for do- mestic supply only, but the others are designed for both domestic supply and irrigation. The conditions are very variable, however, and the fact that the design of pumping plants requires specialized training is well illustrated l)y the list. It is to be noted that no two Arizona Agricultural Experiment Station 487 table XXI. — Experiment station pumping plants WELIj PUMP en GIN Rated power Location Type o ® HP ■25 1 Type V tr. eS 0-g Type Ft. Ft. Ft. Gal per min. H.P. Farm at Tucson. . . . Caisson with two feeders 90 15 10 Hor. centr. 720 Oil engine 15 Farm at Mesa Caisson 40 25 4 He:, rotary 62 it 41 5 Yuma Date Orchard Driven 90 12 Vert, plunger 25 li U 2K' Prcscott Dry Farm Drilled 318 265 Vert, plunger 11 Gasoline engine 6 Cochise Dry Farm. . Bored 130 75 Double- acting plunger ICO Oil engine 6 Irrigation laboratory Dug and drilled 281 81 Temporary, for testing well 10.6 Vert, turbine 705 Motor, 35 belted Permanent, for campus supply,. Hor. centr. 40n Motor, direct- fonnected 20 wells are of the- same type, 3'et each is best adapted to the local conditions. The Mesa and Yuma plants are new. For the Mesa plant a rotary pump was selected, because of the shallow water table, the moderate yield and the necessity for pumping extensively on two different lifts. The pump is set just above the water level and is self-priming. The engine is depressed in a pit, which will become the basement of a small building later on. This arrangement ob- viates the necessity for a long belt. For the Yuma plant a recipro- cating pump was chosen on account of the small discharge. The, driven well being too small to admit a i)ump cylinder, a pit was, dug to the water table, the well pipe was cut off and threaded, and the cylinder was attached directly to the pipe. This scheme assures the greatest possible draw-down and, therefore, yield. The engines are nearly all oil engines (that is, they burn tops, a low-grade distillate), with the exception of the irrigation labt)ra- 488 TwijNTY-EiGiiTH Annual Report tory, for which electric current from the central power plant of the University is available. The engines are all of the four-cycle type, and it may be added that the Experiment Station strongly recom- mends that type in preference to two-cycle hot-ball engines*. This department has designed also a new water supply system for the University campus during the past year. The new system is unique and its main features should go on record at this time. The pump room is situated in a l^asement 74 feet ])y 24 feet. At one end is a reinforced concrete sump of 48,000 gallons capacity, into which the discharge from the well is delivered. The pressure jfumps are in duplicate, of 100 gallons per minute capacity, and start automatically when the water pressure drops to 26 and 23 pounds per square inch. When the pressure reaches 33 pounds, the pumps stop automatically. The discharge line is connected with a 5,000-gallon pneumatic pressure tank which is kept about two-thirds full of compressed air. Floor space is reserved for another pressure tank to be added later, and the remaining space is for fire service pumps. The new system is giving good service, with better pressure than was had formerly with the elevated tank. EXTENSION WORK For two months during the height of the pumping season in 1917, this department kept one of its assistants in the field assisting farmers with refractory engines and pumps, and helping them to secure better fuel economy. The Casa Grande Valley and the McAllister and Whitewater districts were covered in this way. The irrigation engineer devoted two weeks in June, 1917, to lec- turing in Navajo and Apache counties. Ten lectures were delivered. During this trip and throughout the year assistance has been given to farmers and canal companies on irrigation and other farm en- gineering subjects. GRADING LAND FOR IRRIGATION Considerable study has been given to the subject of preparing land for irrigation, particularly land on relatively heavy slopes as from 25 to 100 feet per mile. The principal agricultural valley lands in Arizona lie at slopes of 8 to 15 feet per mile, and these, lands can be irrigated very efficiently. On lands that take water * Vide Bui. 74, Ariz. Agr. Exp. Sta., pp. 429-433. Arizona Agricultural Experiment Station 489 readily the water can be run parallel to the steeper side of the field, Vv'hile on the heavy clay soils the flatter grades are used. With the extension of agriculture to lands farther from the rivers, steeper slopes are encountered, and during the past year much new land with slopes of over 25 feet per mile has been devel- oped. The question has arisen as to the desirable slope in which to lay out the borders or rows. In one locality 8 feet per mile has been adopted arbitrarily, although it has entailed much greater ex- pense for grading than would a steeper grade for the direction of irrigation. Moreover, the flatter grade introduces a heavy side-fall, or cro.'^s-slope, which may become very troublesome during irri- gation. The question involves the possibility of irrigating in furrows or lands with steep gradient. Can the field be wetted uniformly? The efficiency of irrigation depends upon the uniformity of distribution even more than upon the average depth applied. If a large unit head of water is turned into each land or furrow, the soil may be washed or eroded, or, on clayey soil, the water may reach the lower end and be turned off before much has been absorbed. If the head is too small, then on sandy soil it will be absorbed in the upper part of the field and the lower part of the field will receive a rela- tively light irrigation. But the head can be varied between quite wide limits, and it should be the dependent variable. On each field it is necessary to ascertain by trial the optimum quantity for the unit head. The length of the furrow, likewise, can be varied if taken in time. One rancher in the Salt River Valley during the past sum- mer ran water in furrows 330 feet long and his neighbor ran the same stream, when it came his turn in the rotation, in furrows one- half mile long. Many cases have been noted where water has been wasted downward by deep percolation below the reach of plant roots in the upper part of fields, and the cause assigned has been that the lands were too long. But in most cases the waste of water could be prevented by turning the direction of irrigation so as tcj get more slope or, the more practical way, by increasing the unit head of water. On the other hand, sometimes the rancher finds that the lower part of his field is getting the larger proportion of the water. Usually he wishes to regrade his field so as to have less fall in the lands, but his more rational solution is to reduce the unit head. The character of the soil, the crop, the slope, the length of run 490 Twenty-eighth Annual Report and the unit head are interdependent upon each other. Any one may be taken as a function of the others, and the efficiency of irri- gation is a compound function of them all. In many cases of laying out new projects, the head of water has been assumed as one of the independent variables, and the slope for the furrows has been made to conform thereto, but probably the better way would be to run the water down the natural slope and thus save in the cost of grad- ing and obviate the troubles accompanying a heavy cross-slope, and then regulate the length of furrows and the unit head to obtain a uniform distribution of the water. The importance of problems in the application of water is indi- cated by the fact that great diversity of practice exists through the State. The Yuma and Salt River valleys use the border method largely, the Upper Gila Valley uses the border method, but often without the borders, the Little Colorado region practices the corru- gation system as in the Northwest, while in Yavapai County the Colorado method of flooding from field laterals prevails. In all of these sections the water is run down the natural slope, except in the Yuma Valley, wdiere it has become the custom to grade the lands level. A discussion of land grading for irrigation has been contributed to the technical press.* WATER RESOURCES At the time of the entrance of the United States into the world war, a survey was made of the condition of irrigation water sup- plies in Arizona**. On the whole conditions were found to be favorable. Two years of exceptionally heavy rainfall had filled the Roosevelt reservoir and had caused increased flows in all the streams of the State. It was obvious that the limiting factor in the increase of agricultural production in this State would not be the water supply, but rather the amount of labor available. Indeed, it was possible the past summer to grant temporary water to 15,000 additional acres in the Salt River Valley. Since the time of that survey, the abnormally low rainfall in the important watersheds of eastern Arizona has made our water supplies a matter of grave concern. Already the Upper Gila Valley and northeastern Arizona have felt the water shortage and the Roosevelt stored supply has been reduced 35 per cent. Attention is again called to the need of storage on the Gila River. To the great ♦Western Engineering- IX, 1. Jan., 1918. **Arizona Magazine VII, 7, May, 1!»17. Arizona Agricultural Experiment Station 491 misfortune of Arizona, there has been enough water wasted through the San Carlos reservoir site during the past three years to have filled the proposed reservoir five times. The most feasible reservoir site on the Gila River is at San Carlos, and the efforts of the entire State should be concentrated on obtaining that reservoir at the earliest possible moment. Groundwater supi)lies also are dependent u])on the rainfall, but the effect of seasons of high and low rainfall is not so quickly felt as in the case of surface supplies. THE PKoi'osi'i) stativ watKr code Special eft'ort has been made, whenever possible, during the 3'ear to present the merits and the urgency of the modern water code, with its ideal system for adjudicating existing water rights without litigation, for initiating new rights, and for State control and distribution of water supplies. A paper outlining the proposed code and relating the success of the modern system in the other irrigated states of the West has been published as Extension Cir- cular No. 11. Five meetings have been addressed on the subject, and resolutions were adopted by the Second Arizona Irrigation Conference and the National Irrigation Congress urging Arizona to fall in line with the other states. G. E. P. Smith, Irrigation Engineer. A. L. EngEr, Assistant Engineer. AGRICULTURAL EDUCATION The University of Arizona College of Agriculture is especially concerned at this time in meeting the emergency educational re- quirements that it may be made to serve. The opportunities that now await the trained agriculturist particularly relate (1) to active farming operations in which any one with a fair degree of skill and business ability has now unusually good chances to prosper. Such staples as alfalfa, with dependent livestock industries ; cotton, and others of the fifty commercial crops that may be growai in this region, offer varied opportunities for the exercise of skill and ad- vanced knowledge on the part of the investing proprietor. Land values are yet comparatively moderate in this region and young men with agricultural training and some practical experience on the farm are recommended to take up farming as a permanent occu- pation. (2) Many opportunities in agricultural industries, those directly connected with farming operations, afford a second class of opportunities for which scientific agricultural training is indispen- sable. Creameries, canned-milk factories, dairies, alfalfa meal mills, canneries, small packing houses, pickling establishments, cotton gins, oil presses, fruit-drying establishments, pedigreed seeds, pure bred livestock, and fancy specialties of all kinds are instances of the industries that, properly conducted, may become foundations for profitable businesses. (3) Professional agriculture affords still an- other class of opportunities to the agricultural college graduate. At this time there is an unusually strong demand at excellent salaries for trained men to serve in technical Government positions, as county agents in the Extension Service, as reclamation and forest service employes, and as teachers of agriculture in schools and colleges. In the wide field of Southwestern agriculture we therefore have opportunities suited to every temperament, to dift'erent de- grees of training, and to varying personal situations ; and particular effort is being made at this time to bring those young men and women not otherwise called upon for service in time of war to entjr some one of the several educational courses in agriculture ofi'ered for their consideration. The College of Agriculture has attempted to so arrange the cur- riculum that students who have taken a large part of their instruc- Arizona Agricultural Expb:rime:nt Station 493 tiun in other colleges may complete their agricultural education at the University of Arizona without loss of time or credits in making tiie change, and thus avail themselves of the opportunity to obtain a working knowledge of the various types of farming practiced under semi-arid conditions. For this reason, and also because of the strong migration of new families into the Southwest, the larger part of our agricultural student body enters with advanced credits, some coming each year for their senior year's work. This condition has been met by group requirements with a minimum of specific requirements in the four years' course rather than a rigid sequence of subjects which would be practicable only for those entering as freshmen. Consistent with the requirements of four-year courses m other Agricultural Colleges, about one-half of the total units neces- sary for graduation are in the pure sciences on which agriculture rests, in English and other modern languages, mathematics, draw- ing, economics, and military tactics. A smaller number of units, totaling 25, is required in a few specific agricultural subjects which are considered essential in the successful pursuit of any line of agricultural work. To insure that the student specializes sufficiently to take a position in some particular field, a major of 16 additional units in one of seven groups is required. The groups are agronomy, horticulture, animal husbandry, agricultural chemistry, biology, rural engineering, and economics. An additional 14 units chosen from the major group or from other agricultural subjects are re- quired to round out the student's purely agricultural training. The balance of the 124 required units, amounting to six units, are free electives. This elastic requirement permits the arrangement within its limits of courses to meet the needs of the individual who wishes to prepare for professional work, or to engage in farming, or who comes from other colleges with his course nearing completion. A special four years' vocational teacher's course in Agriculture is also offered for those who wish to qualify for service under the Smith-Hughes Act. The essential difference between the voci- tional teacher's course and the regular course is the substitution of sufficient work in psychology and education to meet the State requirements for a first-class teacher's certificate, and of cert'iin desirable courses in agricultural education. The four-year courses are open to high school graduates and to ])ersons 21 years of age who have not completed the usual entrance reciuirements, such persons being permitted later to substitute col- lege credits for deficiencies in preparation. To meet the urgent 494 T\vi!;nty-i;igiith Annual Report — I U I— ( « o o E-i d (U c E J! "^ ^ .^2 2s bCO o ON o o On 30 o CO rvj p ro C^l •*_ rv. (\1 p t>! 00 vd ■^' ■—'•—< 00 t-^ 0\ vO ■* (^1 ■* r^ NO (^1 <^ o ro 00 m- iri (^1 V^ 00 y^ (M 0\ CM o 00 00 o 00 00 'or^ CO t^ On NO r-s. (^i (Ni 00 On ro ro r^ ro •— I On C'l On CO ■* -^ NO Tf O <^ O fO p CN) O; 00 p O On On 00 On O CO »r) O t^ f^l r^ 1^ in t^ -^ ■— I ,—1 ^ CO -»-• 'Xj 1> ^ . en n 5 ^ (71 5 3-0 ra c p .:;'' o u oj o ^- ^ o "t^ ^ CL, a; rt -^ u -^ '^ •- tL, fc Ph 'hh < <; Ph o a a- c ^._ ?;^ rt 'X a, rt ' ^J2 5 o o ^ >. o O-^ be .S o) a. n o rt i-' o ^ ^\n rt ^^ j; J feig. 11. Fi- 12. Fia'. 13. Fig. 14. Fitj. 15. Fi-. 16. Fi- 17. Fig. 18. Fit;;. 19. I'ig. 20. Fig. 21. I'jo- 9? llg. 23. Fig. 24. j'lg. 25. Fig. 26. Fig. 27. Fig. 28. Fig. 2<) Fig, 30. Fig. 31. Fig. 32. T" ig. 33. Fig. 34. Fig. 35. Fig. ,36. Fig, ,37. Fig, , 38. 1'ig. ,39. Fig, .40. Fig, .41. Fig ,42. Fig .43. Fig .44. Fig. 45. Fig. 46. PAGE Alfalfa 610 Beans 610 Corn 615 Potatoes 623 Small grains 624 Summary of Sulphur Spring Valley Dry-farm data 641 Sorghums 628 ]\liscellaneijus crops 638 ILLUSTRATIONS PAGE Reid's Yellow Dent corn. Prescott Ury-farm Frontispiece Scene in tlie Petrified Forest, Northern Arizona 501 Scene in the Petrified Forest, Xorthorn .Arizona 501 Amount and distribution of precipitation 510 Amount and distribution of precipitation 511 Amount and distribution of precipitation 512 Amount and distribution of precipitation 513 Ranch in open park in Northern Arizona forest 515 San Simi:n Wash near Solomonville, Arizona 528 Papago rioodwater ditch. Pima County, .\rizona 531 Papago well, showing' method of raising water 531 Chemue\ i Indian field subject to annual inundation 534 Yuma Indian field of corn and beans 534 .Apache village and farms. Northern Arizona 536 Wash on the Snowflake Dry-farm, showing uniformity of soil 541 Dent corn and beans. Snowflake Dry-farm 544 Corn, Snowflake Dry-farm. 1911 548 White Dent corn, Snowflake Drv-farm. August 17. 1912 549 Corn, Snowflake Dry-farm, June 22, 1915 549 Potatoes a o O o S 0) u a 3 C C d C d Flagstaff 5 6.0 7.0 9.0 90 10.0 9.0 7.0 5.0 7.0 7.0 6.0 7,0 7.4 Fort Grant 12 6.4 73 7.4 80 7.5 7.4 6.3 5.9 7.0 6,8 6.7 1 6.5 6.9 Fort Apache.. 9 5.0 6.1 6.8 8 2 7.9 7.7 6.0 5.4 5.8 6.1 5.4 5.1 6.3 Phoenix 18 3.6 42 4.7 4.8 5.0 ^ 4.8 4.7 4.6 4.3 4.1 3.8 3.6 4.4 Tucson 8 4.7 5.7 5.6 59 5.6 5.5 5.1 4.6 4.6 5.6 5.2 4.9 5.2 Yuma 35 6.3 6.8 7.0 7.2 6.8 ,6.1 6.7 6.1 5.1 5.1 5.7 6.2 6.2 In general there are two precipitation maxima, one in midwin- ter and one in midsummer. Winter precipitation, which is of great- er importance in northeastern Arizona, occurs either as snow or a gentle downfall of rain and penetrates quite completely into the ground. Individual showers usually cover a considerable territory. Summer rains, of primary importance in southern Arizona, occur as local torrential showers often lasting but a few minutes and rarely continuing more than a couple of hours. It is difficult to have these rains penetrate well, since one-half inch of precipitation, occurring in a few minutes, is apt to start a considerable surface runofif, and occasionally more than 75 per cent of the heavier showers is lost in this way. The mean annual precipitation varies with the altitude ; but, owing to local topographic features, this variation is usually not in direct proportion. For example, the mean annual precipitation at Tucson, altitude 2425 feet, is slightly greater than at Snowflake, altitude 5644 feet. This is due to the somewhat abrupt southwestern border of the Colorado Plateaus Region. The sudden increase of altitudes causes precipitation of a great deal of moisture from southwestern winds, and it is not until these winds reach a considerably higher altitude that much further precipitation takes place. A second example is that of the Prescott Dry-farm which receives fully two inches less moisture each year than Pres- cott, about seven miles south, while Jerome Junction, about ten miles north, receives still less. The difference in altitude between 506 JJULLIiTIX 84 these places is insufficient to account for the variation in precipita- tion. Table III records the rainfall in these three localities in the summer of 1912. TAHLH; III. LOCAL VARLVTION OF RAINFALL, 1912 Prescott Prescott Dry-farm Jerome Junction Date Elevation 5320 ft. Eevation 5008 ft. Elevation 4650 ft. ■ 1 lie lies Inches Tulv 13 .56 . . ■• 14 .16 > < • , . " 15 .02 • 16 .98 .11 , . " 17 .16 2.07 , . " 18 .75 .43 " 19 .20 .15 , , •• 20 .05 .02 , , •' 21 .02 < > • • , , " 24 .23 .30 , , " 25 .85 .60 , . • 26 1.93 .95 , , •• 27 .18 , , " 28 .11 .40 , , ■• 29 .22 , , . •• 30 .12 .60 , , •■ 31 .24 .49 Total 6.20 6.70 3.66 Aug. 12 .02. j , " 13 .26 .05 .07 " 14 1.00 .11 .10 " 19 .02 9? .05 • > • " 23 .05 .... .02 •• 24 .04 .25 ■' 25 .07 •• 26 .08 • • • ■• 27 .27 .35 • . • '• 28 •• 30 .17 " 31 .37 .02 .02 Total 2.09 .58 .72 Sept. 30 .30 1 .01 Oct. 1 .13 .26 .21 " 2 .31 .17 " 3 .03 . . . . " 4 .92 .20 .24 " 5 1.88 .75 .75 " 6 .01 .06 " 10 .08 .61 " 27 .86 " 28 .6i " 29 • • . • .27 Total 4.22 1.99 1.54 r-rand Total .... 12.81 9.27 5.93 Climatology • 507 A third interesting example of localized precipitation is found in the Sulphur Spring Valley. McNeal, having an altitude of 4150 feet, receives a mean annual precipitation of 15.70 inches; Cochise, altitude 4219 feet, receives 11.41 inches; and Willcox, about the same elevation as McNeal, receives only 10.67 inches. Table IV records mean monthly precipitation, and for convenience in study is grouped into four districts as follows: (1) The Little Colorado Drainage Basin; (2) Other localities above 4000 feet elevation; (3) Localities between 2000 and 4000 feet; (4) Localities below 2000 feet. While the mean annual precipitation is indicative, the distribu- tion of rainfall is of primary importance. For illustration, indi- vidual showers of one-quarter or one-third inch, occurring at inter- \als of two or three days have no real value, and often necessitate considerable work to preserve a mulch. An inch of precipitation falling thus intermittently may be detrimental ; whereas, if the showers had come very close together, or if an inch of precipitation had fallen in one or two showers, the effect would have been bene- ficial. While an inch of precipitation falling in one hour moistens the soil to some extent, it is largely lost by surface runoff'; whereas an inch of precipitation falling over a longer time more completely enters the ground. The amount of moisture lost by surface runoff' is great, often being sufficient to close all trafffc for several hours at a time even on main roads. Since so much value is lost in this manner one of the problems of successful farming is ])roper utilization of floods. In this y\rizona Indians are masters. There are thousands of acres within the State which may be irrigated occasionally by these floods. Figures 4, 5, 6, and 7 graphically illustrate the amount and distribu- ticjn of precipitation at representative Arizona localities. •a o o P o be 3 (0 c >. d § u nJ c 1 c > o iCOlOOO«30qc^^c^;0;Ot-icOCT; rl-OOOVO"^VOCMNN ID •«*; ^. CJ O vo O CO vq Co«-: c: lo ^) <^'. .— '— CN 'cm ^ CM >-"-' CMCM •- ON c^ i=. \0 OC O Tt-_ C t^. 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C^l C^l Cs| 't ^ c; 1 c > o OO vOC c r^toOOsr^lvC C:CvCi/-)vCC;'— 'COC SC CO CO f^ — CO C^ 1 to IT) CO ^ in o O -^ O >J~> <* 1 <^l O C t^ ^1 u-> c. LO CM — o ■* ■^ ^'- OI^LOCO*^Osl\VilCO<^ K^ .— 1 (N) Oslo VT; "T^ 00 so c ro 1^1 f^i T)- U-, or o <^i ST c/" CO' — COt^'— •*TCO' — SO — irjiO Tj- \o -* ro CM CM ro C^^ ro C^l C^i CM * '-J 1^ o o •' o a- J- r; T ^ CSj ct E : 6 ■o ' S4-. " -4 510 Bui^i^ETiN 84 :^ ^ ^ ^ ^ ^ " ^' k ii 0 0 p aj j O ^ Q LAKE.3IDE. \ i 1 ! i 1 ^noivrLA KE. \ \ 1 ll I 1 ll PitfE:DALl Z^ T • t M III 1 / O 5 F^LAG^TAFF 1 1 r I 1 1 _....l ^_. Moccasin ■ ■ ll 1 J 1 4- ^T. UOHN.5 1 T 1 1 1 1 -*— 1 F-g. 1. — i\m Hint and distribution of ])reciiHtation at i-ei)i-e.seiUative Arizona localities. Climatology 511 c '1R.AISD CANy^opf 1 X 1 1 1 1 — 1 1 1 i •0 - 3 ? S i ^ i § ? '^ ^ 0 ^ S Williams 1 ' 1 1 1 ; 1 1 - - _^-X-i--i- P R^El^COTT 4 ^ it^coTT Dry Fa£M 1 i 0 n i f i ! 1 1 1 -J 0 Li— 1 1 J_ ! 1 : 1 s5E:.LI GMAN ^ KiriGMAH ^ q ' \ i i \ — \ — 0 T T / 1 1 . 1 1 r 1 - n U-J- 1 1 -M— I 1 ii Fig-. o.—Ainount and distribution of precipitation at representative Arizona locations. 512 Bulletin 84 '^ 2 ^ b ^ y^ ^ ^ ■^ ^ ^ ^ "J ^ ei t X; --1 s c^ k ii: 0 o p ilJ O ^ Q J PlHAL^ 12. An 'CH II 1 1 1 r O/ZT HUA CHUCA 1 _ 1 il 1 '0 o O ^- "Ci fSi 1 ^ ^- ^5 !^ k i^ u ^ ::J ^5 "^ u 0 4j Tucson 1 1 f I 1 |- AlLAIQ,E:^ i Q,AncH 1 h'' 1 JL I 1 1 rOlZT GRATiT cr EiOWIEL <3 O 1 L T I 1 I - -L I 1 1 1 Fig. 6. ^Amount and distribution of precipitation at representative Arizona locations. Climatology 513 ). ^ 11 ^ « ^ K ^ ^ ^ ^ S '^ s 0 Q fV/LL.CO>C » r I 1 1 1 GlLy\ £>BND •0 0 2. 1 O O ii ti ci S k ^ ^ i:^ ^^^ K U O y^uA^^ 1 1 T 1. 1 1 1 Phobnix 1 I r » Il 1 1 Fig. 7. — Amount and distribution of precipitation at representative Arizona locations. PRINCIPAL DRY-FARMING REGIONS LITTLE COLORADO DRAINAGE AREA While soils of the Little Colorado drainage area are quite variable, they may be divided roughly into four classes : river bot- tom, first mesa, variegated intermediate, and timber soils. A com- paratively large area of fairly uniform soil of each type may be found. The river bottom soils are deep and very fertile, but often con- tain excessive amounts of alkali which in some cases render them valueless. Usually river bottom soils occur as clay loams with occasional patches of clay or adobe soils. The fine texture and lack of humus causes them to crust and bake during dry weather, and often they are hard to till except when they contain the optimum percentage of moisture. Being deep and fine, soils of this type re- tain moisture very well, though water penetration is not rapid. Soils of lighter texture are found in extensive areas, notably at Woodruff, Winslow, and St. Johns, and the broad mesas north of Holbrook and Adamana. These lands, classed as first mesa soils, are easier to till because of their lighter texture, and are more readily permeable but less retentive of moisture. No alkali is found in the first mesa soils, which have resulted from the decomposition of red and brown sandstones. The fertility is not so high as that of the bottom lands. The variegated intermediate soils occur at the mouths of num- erous draws and arroyos, and in little valleys along small creeks between low rolling hills. Because of their diverse origin varie- gated intermediate soils are not uniform and usually occur in small tracts, notably areas of silt soil of considerable depth in the Dry Lake region, at Cottonwood Wash, and on Silver Creek, all in the vicinity of Snowflake. Soils on the higher elevations in this vicinity are too shallow for dry-farming, usually being from one to four feet deep. Thus, the large, gradually rising region extending southward from Holbrook to Shumway is characterized by a shallow soil, only the wider valleys containing soil adapted to dry-farming. Except for grayish brown silt soils near Snowflake the prevailing color is reddish brown as a result of decomposition of sandstone capped by a thin veneer of limestone. Mechanical and chemical analyses of I'kimu'al ^)R^■-FAR^^X(; Ri-.cioxs 515 soil sam]iles fnnn the Snowflake Drv-farm. wliich are typical of the valley soils of this rciiion, arc reported in Tables \' and \'l. The mechanical analysis shows a high percentage nf clay and silt ni the fourth ft.ot. and a high percentag^e of very fine sand and low ])er- centage ui clay in the eighth foot. The soil is a fine sandy loam containing sufificient clay to insure lasting fertility, and enough silt and very fine sand to jjrevent liaking. Soil of this type is easily tilled and allows the economical use of moisture. The chemical analysis indicates a fairly rich soil, free from injuri(nis amounts of alkali. Fig. 8. — Ranch in opm iiark in Nortlicin Arizona forest, 6500 feet elevation. 516 Bulletin 84 TABLE V. MECHANICAL ANALYSIS OE SOIL FROM SMITH FIELD, SNOWFLAKE DRY-FARM Average Very Medium Fine fine Silt Clay .sand sand sand % % % % % 4.8 27.7 23.9 21.6 17.2 3.5 29.4 25.1 22.3 16.7 1.3 15.3 27.6 34.4 20.4 .6 13.0 23.0 40.6 22.4 .6 17.7 31.0 32.4 17.6 2.7 21.8 22.9 28.3 21.0 1.6 25.0 32.0 22.9 17.4 1.1 24.0 38.6 20.1 15.0 2.02 21.73 28.01 27.82 18.46 Note- The .separates referred to in the mechanical analyses eiven in this bulletin are those of the U. S. D. A. Bureau of Soils. Fine grravel, diameter 2 to 1 millimeters; coarse sand, 1 to 0.5 mm.; medium sand, 0.5 to 0.25 mm.; fine sand, 0.25 to o.lO mm.; very fine sand, 0.10 to 0.05 mm.; silt, 0.05 to .005 mm.; clay, less than 0.005 mm. TABLE VI. CHEMICAL ANALYSIS OF SOIL FROM SMITH FIELD, SNOWFLAKE DRY-FARM Phos- Alkali Solu- Calcium Acid Pot- phoric) Lima Nitro- ble Chlo- and mag- Composite in- ash acid (CaO) gen Humus solid! rides nesium sample soluble (K2O) (P2O5) (N) dried at 110" C. ai NaCl sulphates and chlo- rides as CaSOi % % % % % 7n % % % 1st 4 feet 84.470 .517 .089 2.987 .(^2,7 .079 .128 .004 .033 2nd 4 feet 82.959 .834 .075 3 533 .055 .540 .128 .004 .065 Av.?. 8 feet 83.714 .675 .082 3.260 .046 .310 .128 .004 .049 Note: The chemical analyses of dry-farming soils reported in this bulletin refer to that portion of the soil solub'e i" hydroch'oric acid. 1.115 sp. err., according to the methods of the Association of Othcial Agricultural Chemists. The alkali de- terminations refer to the .salts soluble in water when 50 erams of soil are disrested with 1000 C.C. water for ten hours on the water bath. Arizona Agricultural Experi- ment Station Twenty-fourth Annual Report, p. 275. Extensive areas of agricultural lands are found in open parks and on the larger flats of the timber belt. These soils are largely decomposed lava of very fine texture in the bottoms, and coar.se and gravelly on the slopes. The best agricultural soils within the timber belt are loams of medium texture, though coarser types produce well under the rela- tively heavy precipitation of the region. These soils are fairly per- meable and retain water very well with reasonable cultivation. The Principal Dry-Farming Regions 517 bottom lands are of fine texture and lack organic matter. Water penetration is slow but moisture is retained efficiently. Adobe soils also are found in the bottoms. They are low in humus and nitro- gen, baked in the dry season, and are difficult to till. They are rela- tively fertile, however, and if plowed in the fall and exposed to freezing- and thawing in winter are handled with less difficulty. The most interesting lava soils within the timber belt are found near Lakeside, east and north of Showlow Creek and around Flagstaff, but soils little affected by lava occur at Scott's Flat, the mesa south- west of Showlow, the Linden vicinity, and the Pinedale region. Table VII records a chemical analysis of soil from a farm near Linden, which had been under cultivation for two years. It shows less nitrogen and humus than the lava soils around Flagstaff but contains nearlv three times as much lime. TABLK VII. CHliMICAL ANALYSIS OP SOIL FROM NRAR LINDEN Phos- phoric acid (P2O5) Lime (CaO) Nitro- gen (N> Humus Alkali Composite sample Acid in- soluble Pot- ash (K2O) Solu- ble solidi dried at 110° C. Chlo- CaandMg rides sulphates ag and chlo- NaCl i rides as j CaS04 1st 4 feet 2nd 4 feet % % 84.983 .402 84.100 : .500 % .097 .105 % 3.258 3.233 .052 .028 % .700 .750 % 1 % % .128 .004 .000 .140 .012 .022 Ayr. 8 feet ''84.541 .451 .101 3.245 .040 .725 .134 008 Oil Another type, a scoriaceous soil, occurs on slopes of volcanic cones and ridges. It is quite coarse and porous, absorbing water readily and giving it up easily. This soil is composed of a mixture of slag and pumice-like detritus, and is red, gray, or yellow in color. The cinder soil east of San Francisco Mountain is worthless for agricultural purposes and is barren, save for a few quick growing annuals which utilize moisture from summer rains. In Tables VIII and IX are recorded mechanical and chemical analyses of a typical lava soil sample, taken from a field at Cliffs in which grain and potatoes had been grown for five or six years. The lava soil contains more coarse material than the soil from Pipe Springs Valley or from Linden, but the larger amount of clay and silt insures lasting fertility. The percentages of nitrogen and humus are relatively high, and there is a medium phosphoric acid content. 518 r.lLLKTIN 84 TABLK VIII. MECHANICAL ANALYSIS OF TYPICAL LAVA SOIL FROM CLIFFS Very Sample Fine Coarse Medium Fine fine Silt Clay gravel sand sand sand sand % % '/r % % % % 1st foot 3.0 9.4 6.3 15.0 12.3 40.8 13.2 2nd '■ ... 1.2 9.8 4.0 14.4 14.0 41.9 14.5 3rd " ... 5.0 10.1 5.0 15.2 12.3 39.0 13.2 4th - " ... 1.6 3.1 1.4 69 15.9 52.3 18.8 5th " ... 4.2 5.9 2.9 9.4 11.5 47.7 18.2 6th " ... 1.6 5.2 3.0 119 16.7 47.6 142 7th " ... 1.9 7.6 4.8 17.0 17.5 40.9 10.6 8th •■ ... 3.8 10.3 6.1 20.8 17.9 30.5 11.0 Average . . . 2.79 7.67 4.19 13.82 14.76 42.59 14.21 TABLF IX. CHEMIC.\L AN.\LNSIS OF TYPIC.VL LAVA SOILS FROM CLIFFS Acid in- soluble Pot- ash (K2O) Phos- phoric acid (PaOs) Limii (CaO) Nitro- gen (N) Humus Alkali Composite sample Solu- ble soIidT dried at 110"" C. Chlo- rides a^ NaCl CaandMg sulphates and chlo- rides as CaSO, 1st 4 feet 2nd 4 feet % 80.112 70.596 % .413 .892 .652 % .083 .075 .079 % .962 1.265 1.113 % .061 .108 .084 % 1.160 .560 .860 % % % Avg. 8 feet 75.354 VALLEYS OF WESTERN COLORADO PLATEAUS PROV- INCE AND NORTHERN ARIZONA HIGHLANDS REGION The area described below extends westward from the Arizona Divide, which diverts drainage from the Little Colorado on the east and north to the Colorado River, and southward from Fre- donia to Wickenburg. There are wide variations in soil, tempera- ture, and precipitation. I'lic larger valleys of importance include Lonesome, Big Chino, Little Chino, Aubrey, Hualpai, Detrital, Sacramento, and Big Sandy. The smaller interesting valleys are Williamson, Skull, Kirkland. Peeples, and JMcMullen, which are occupied mostly by cattle ranches. LONESOME AND LITTLE CHINO VALLEYS Lonesome and Little Chino Valleys, having the same topo- graphic soil and climatic conditions, and merging into one anoilier. Principal Drv-Fakmixg Rrcions 519 should be considered together. Probably 150,000 acres suitable for dry-farming are included. Granite Mountains on the south and west, and the Black Hills on the east and north almost completely enclose these valleys. The two ]M-incipal drainage streams, Granite and Willow Creeks, flow north and east, and in the rolling to- pography of the valleys numerous floodwater courses have been formed. All drainage courses converge near Del Rio, forming one of the main tributaries of the Verde River. Rapid water erosion takes place in the flood season, and me- andering of the larger streams causes depositions of great quantities of sediment on either side of the floor of the valleys forming a very fertile silt soil. A fairly coarse loam is found on the first mesa im- mediately adjacent to the creek bottoms, and a gravelly loam occurs on frequent knolls in the valleys, though neither of these loams is as fertile as the silt soil of the bottoms. All three soil types are found on the Prescott Dry-farm. Tables X and XI give the mechanical and chemical analyses of the silt soil deposited in limited areas along the stream courses of the Little Chino and Lonesome Valleys. It contains a large percentage of nitrogen and humus, and is very fertile. Tables XII and XIII give the mechanical and chemical analyses of the intermediate loam on the Prescott Dry-farm. The sample is typical of the prevailing soil type of the region. The high percentages of silt and clay classify this soil as a fine loam. It is permeable and retains moisture quite well. The percentages of nitrogen and humus are fairly low, though the soil shows relatively high fertility. TABLE X. MECHANICAL ANALYSIS OF SOIL FROM BOTTOM LAND, PRESCOTT DRY-FARM Very Sample Fine Coarse Medium Fine fine Silt Clay g:ravel sand j sand sand .sand % % '/r ^r <^o '7o % 1st foot 7.4 15.8 7.6 20.2 180 229 8.0 2nd " .... 39 10 4 4.2 147 23.2 31.9 11.3 3rd " .... 7.6 14.8 6.4 213 20 5 21.5 8.1 4th " .... 59 154 7.2 99 S 20.4 20.8 l.(^ 5th " .... 4.5 8.6 4.1 17.1 22.6 30.8 118 6th " .... 11.2 23.0 8.2 i 23.1 t 14.4 13.1 6.6 Average . . . 6.75 14.7 6.28 ' 19.81 19.85 23.5 8.90 520 Bljllictin 84 table; XI. CHEMICAL ANALYSIS OF SOIL FROM BOTTOM LAND, PRFSCOTT DRY-FARM Composite sample 1st 2nd feet feet Acid in- soluble % 80.820 84.917 Avg. 8 feet 82.868 Pot- ash (KoO) .481 Phos- phoric acid (PsOb) % % .532 .190 .430 i .164 Lima (CaO) % 1.650 1.320 .177 1.485 Nitro- gen (N) Humus % .085 .063 .074 % 1.400 l.OCO 1.200 Alkali Solu- ble solids dried at 110° C. % 0.192 O.ICO Chlo- rides as NaCl CaandMg sulphates and chlo- rides as CaSO, % .012 .008 .146 1 .010 % .044 .011 .027 TABLE XII. MECHANICAL ANALYSIS OF INTERMEDIATE LOAM, PRESCOTT DRY-FARM Very Sample Fine Coarse Medium Fine fine Silt Clay gravel sand sand sand sand % % % % % % % 1st foot 40 6.4 2.0 5.0 17.4 48.3 16.9 2nd " .... 5.1 7.6 2.8 6.6 12.6 33.4 31.7 3rd " .... 40 7.9 3.0 8.5 12.4 35.1 29.2 4th " .... 7.6 15.6 7.0 16.6 10.9 24.6 17.4 5th " .... 5.0 12.9 6.8 20.7 11.6 26.6 16.7 6th " .... 112 13.8 5,2 13.6 12.2 26.4 17.5 7th " .... 2.4 3.2 1.0 4,4 162 52.2 20.6 8th " .... 8.4 17.9 10.66 7.6 4.42 18 0 11.67 15.0 13.53 22 8 33.67 10.4 Average . . . 5.96 2005 TABLE XIII. CHEMICAL ANALYSIS OF INTERMEDIATE LOAM, PRESCOTT DRY-F.\RM Acid in- soluble Pot- ash (K,0) Phos- phoric acid (P2O5) Limcj (CaO) Nitro- gen (N) Humus Alkali Composite sample Solu- ble solids dried at 110- C. Chlo- rides as NaC! CaandMg sulphates and chlo- rides a.s CaSOi 1st 4 feet 2nd 4 feet % 80.059 80.863 % .395 .510 7o .328 .209 % 1.760 1.457 % 0.044 .013 % .600 .310 % .148 .148 .148 % .012 .016 % .022 .044 A.vg 8 feet 80.461 .452 .268 1.608 .028 .455 .014 .033 The native vegetation consists of gramas, six weeks' grass, and scrub oak. Water for domestic purposes may be obtained at depths ranging from 40 to 50 feet in the center of the valleys, and from 300 Principal Dry-Farming Regions 521 to 350 feet at higher elevations. Excellent dam sites are available with sufficient drainage areas to allow the irrigation of possibly 15,000 or 20,000 acres. Precipitation varies from twelve to fifteen inches annually. BIG CHI NO VALLKV The Big Chino Valley, about seventy miles long and an aver- age of seven miles wide, joins the Little Chino on the north and slopes towards the northwest. The soil is a fine sandy loam, largely of granitic origin, and is somewhat similar to that of the first mesas of Lonesome and Little Chino Valleys. No precipitation records are available, but the average annual rainfall is probably between twelve and fifteen inches. Apparently, there is ample underground water near the surface for domestic use and a supplemental irrigation supply. A dam site at the upper end of the Valley, subjacent to a large drainage area, makes irrigation of a considerable acreage feasible. AUBREY BASIN Aubrey Basin, forty miles long and an average of ten miles wide, lies between Aubrey Rim on the east, Yampai Clififs on the west, the Santa Fe Railroad on the south, and the Grand Can- von on the north. Drainage is toward the south with no outlet, and there are no water courses of importance in the Basin, ^fhe elevation in the center of the valley is about 5200 feet. The sod is a fine loam resulting from decomposition of red sandstones and gray limestones. In the center of the valley the soil is probably twenty feet deep, while near the edges it is only two or three feet deep. The basin is mostly covered with a growth of native grasses, including grama and galleta, but barren spots are found where the grasses probably have been killed out by overgrazing. In these places the soil is shifted badly by winds. The average annual pre- cipitation is probably about fifteen inches. Groundwater is far be- low the surface. Along the Santa Fe Railroad a small quantity of water is obtained at a depth of 1200 feet; while a strong flow, which rises to within 1000 feet of the surface, is found at a depth of 1600 feet. In the center of the valley a well 680 feet deep furnishes a fairly large quantity of water of excellent quality. 522 BuLLKTiN 84 IH'ALl'AI \ALLi;v Hualpai A'alley, approximately sixty miles long and twenty- five miles wide, extends in a north and south direction and lies im- mediately west of Peacock and Music Mountains. Except at the, north end, it is an undrained basin. Accumulation of floodwater in the center of the basin forms Red Lake, a big muddy flat except (luring the few weeks of flood season. The valley floor is approxi- mately 3000 feet al)ove sea level, and is surrounded by abrupt mountains on either side. The only stream of importance is Trux- ton Creek which is dry most of the year. The soil is a light loam. "Caliche" appears in jdaces but, in general, the soil depth is satisfactory. In the center of the Valley there is considerable soil movement by wind. The native vegeta- tion consists of grama and galleta grasses. At Kingman, located in the low hills on the west border of the \'alley, the average annual precipitation for three years was 7.65 inches, which is insufficient for dry-farming. Underground water may be obtained only at great depths. A well sunk to a depth of 700 feet near the head of the Hualpai Wash failed to go through the toj) stratum of rock debris. Storage of the water of Truxton Creek, which does not seem feasible, appears to be the only method by which Hualpai \'alley can be reclaimed for agricultural ])urposes. BIG SAXDN- \'ALIJ:V Big Sandy \'alley lies south of Hualpai Valley beyond Pea- cock Mountains and Hualpai Peak. Aquarious Cliffs and Aquarious Mountains form the eastern boundary and Aubrey Hills the west- ern. The elevation at Hackberry on the northern border is 3552 feet, and the slope southward is quite abrupt. The X'alley is drained by Big Sandy Wash and its tributaries. White Clifl:', Trout, Abapuk, Spencer, and Sycamore Creeks and Deluge Wash, all of which are dry most of the year. The soil is largely decomposed granite and in many places is shallow. The average annual precipitation is probably from six to eight inches. Little is known concerning the groundwater supply, but it is probably limited and far below the surface. Principal Drv-Farming Re;gions 523 detrital and sacramento valleys Directly west of Hualpai and Big Sandy Valleys, extending north and south from Williams Canyon to the Colorado River, are the Detrital and Sacramento Valleys. Because of similarity of geo- graphical and agricultural conditions these Valleys are considered together. They are approximately 130 miles long and from five to fifteen miles wide. About midway occurs a divide which diverts drainage northward through Detrital Wash into the Colorado River near Stone Ferry, and southward through Sacramento Wash to Yucca, thence westward around the end of the Black Mesa into the Colorado River near Mellon. North of the Grand Canyon the de- pression continues in the valley of the Virgin River. The center of Detrital and Sacramento Valleys is probably about 3400 feet above sea level. The southern half slopes more abruptly than the northern, and the altitude at Yucca is approximately 1800 feet. Precipitation probably averages six to eight inches annually. The underground water is very deep, and wells must be sunk ap- proximately 1000 feet to obtain small amounts for domestic use. The diversion of floods or their storage for supplemental irrigation is feasible in some places. Climatic features of the southern end of Sacramento Valley adapt the region to the growth of sub-tropical crops wherever the water problem can be satisfactorily solved. VALLEYS NORTH OF THE GRAND CANYON PIPE SPRINGS VALLEY Pipe Springs Valley extends north and south for approximately thirty miles, has a width of approximately twelve miles, and lies between Vermillion Cliffs on the east and a local fault line of Antelope Valley on the west. The northern and southern bounda- ries are indefinitely determined, the former being a short, abrupt rise in Short Creek Valley, and the latter a gradual slope to Kanab Creek. The soil of the eastern half of the Valley is mostly de- composed sandstone, while in the center and in the western half there is a considerable mixture of disintegrated limestone. Through- out the Valley the soil is deep, uniform, fairly fertile, and easy to till, but is shifted somewhat by winds. The Valley derives its name from water piped from springs in the Vermillion Cliffs. There are no data concerning the groundwater supply, but from appearances 524 BuLivETiN 84 it is far below the surface. Precipitation at various points averaged about 14.5 inches in 1914. About 300,000 acres of land in this val- ley are adapted to dry-farming, but reclamation will probably be restricted to the area which can be operated by settlers obtaining their domestic water supply from Pipe Springs. Mechanical and chemical analyses of a sample of soil from Pipe Springs Valley are reported in Tables XIV and XV. It is a very fine sandy loam char- acteristic of the region, easily cultivated, and shifted but little by winds. The percentage of clay increases in the deeper samples, and the soil appears to have lasting fertility. It is free from alkali in injurious amounts, fairly well supplied with nitrogen and humus, and rich in lime. This soil closely resembles that of the Southern Utah Experiment Farm at St. George. table: XIV. MECHANICAL ANALYSIS OF SOIL FROM PIPE; SPRINGS, NORTH OF THE GRAND CANYON Sample Fine gravel Coarse sand Medium sand Fine sand Very fine sand Silt Clay 0-15 inches 15-30 30-45 45-60 60-75 % 0.0 .0 .0 .0 .0 % 0.1 .5 .0 .0 .1 % 0.3 .4 .1 .1 .7 % 17,5 10.3 8.0 9.8 10.3 % 46.5 54.7 30.4 43.1 34.6 % 26.8 29.1 44.9 33.4 35.2 % 8.8 5.1 16.3 13.4 19.1 Average . . . .0.0 0.1 0.3 11.1 41.8 33.9 12.5 TABLE XV. CHEMICAL ANALYSIS OE SOIL EROM PIPE SPRINGS, NORTH OF THE GRAND CANYON Acid in- soluble Pot- ash (K,0) Phos- phoric acid (P2O3) Limq (CaO) Nitro- gen (N) Humus Alkali Composite sample Solu- ble solids dried at 110" C. Chlo- rides a.s NaCl CaandMg sulphates and chlo- rides as CaSO, 1st 4 feet 2nd 4 feet 76.144 75.492 % .343 .835 % .128 .112 .120 % 5.170 5.733 5.452 % .028 .036 .032 % .480 .660 .570 % % % Avg. 8 feet 75.818 .589 Principal Dry-Farmixg Rt;GioNS 525 SHORT CREE^K BASIN This basin, immediately north of Pipe Springs Valley, is named from a creek which originates from springs in the Vermillion Cliffs and sinks in the sand at a place about three miles from its source. The soil is similar to that of Pipe Springs Valley. Native vegeta- tion consists of a good growth of white sage, grama grass, and oc- casional patches of bunch grass. The construction of a submerged dam across Short Creek, successful operation of which would make possible the irrigation of 4000 or 5000 acres, is apparently feasible. ANTELOPE VALLEY Antelope Valley, named from Antelope Springs, which rise at its northern boundary, continues south and west from Pipe Springs and Short Creek Valleys and extends in a north and south direction for forty miles with an average width of about twelve miles. It contains about 350,000 acres, and has soil and climatic conditions similar to Pipe Springs Valley. HURRICANE VALLEY Hurricane Valley is separated from Antelope Valley by Hurri- cane Ledge, a red sandstone fault escarpment, which forms its east- ern boundary. The soil is similar to that of Pipe Springs Valley, but it is probably not adapted to dry-farming because of the low precipitation and relatively high temperatures. HOUSEROCK VALLEY Houserock Valley, about thirty-five miles long and six miles wide, is bounded on the north by abrupt cliffs in southern Utah, on the east bv the Vermillion Clififs, on the west by Kaibab Plateau and on the south by the Colorado River. Soils of the eastern por- tion are of red sandstone origin and relatively infertile, while those of the western side are from limestone. "Caliche" is found in many places, and the depth of soil is varied and generally unsatisfactory for water storage. The native vegetation is not uniform, though it furnishes considerable winter grazing for stock pastured in summer on the Kaibab Forest Reserve. The only buffaloes in the State are found in this Valley. There are no data concerning either the groundwater or precipitation, but the practicability of reclamation by dry-farming is questionable. 526 Bulletin 84 KAir.Ar. FORKST reserve; The Kaibab Plateau is a large region capped with surface soil of limestone origin. The maximum elevation is about 9000 feet. The annual precipitation probably averages more than twenty inches, and mostly sinks into subterranean courses which reappear as springs, one of the largest forming Bright Angel Creek which flows into the Colorado River about 2000 feet below the canyon rim. Numerous small drainage courses run through the northern and western parts of the Reserve, chief of which is Tenney's Gulch, which empties into Kanab Creek. Summit Valley, one of the prin- cipal agricultural areas of the north end of the plateau, merges into Telegraph Flat which is continued in the area east of Kanab along Johnson Run. Numerous small parks of fifty to two hundred acres occur at various places on the plateau, but elevations of 7000 to 9000 feet render dry-farming somewhat precarious. Precipita- tion falls largely as snow, and the frost-free season is short. Reclamation by dry-farming in this region is feasible, not so much on the plateau proper, as in the lower valleys bordering the plateau, such as Kanab Creek Valley and Johnson Run. A suc- cessful dry-farm on White Sage Flats, sixteen miles southwest of Fredonia, has been operated since 1910, and has satisfactorily pro- duced wheat, rye, barley, potatoes, beans, and corn. Telegraph Flat, slightly east of north of White Sage Flat, ofifers a consider- able area of similar soil. On the east side of Kanab Creek near Fredonia, somewhat extensive areas of dry-farm lands have been successfully operated for many years. In this vicinity the soils are deep fine loams, except in small basins wdiere they are quite adobe. Alkali is frequently encountered both in the soil and in the under- ground water. About 100 acres near Fredonia with irrigation have produced good crops of alfalfa, small grains, corn, and deciduous fruits. Throughout the region there are excellent opportunities for a combination of livestock and dry-farming where the summer range of the Kaibab Forest Reserve can be supplemented with dry-farmed feeds in winter. VALLEYS OF SOUTHEASTERN ARIZONA At elevations of 3500 to 5000 feet large areas of dry-farm lands are found in valleys of the southeastern part of the State. Chief PrincipaIv Dry-Farming Regions 527 among these is Sulphur Spring Valley, containing approximately 1,000,000 acres. The soil is a fertile decomposed limestone, and "caliche"' ap- pears in many places. A large alkali flat lies east of Willcox and Cochise, and alkali spots, in the vicinity of Whitewater and through- out the southern end of the \^alley, make reclamation of a large part of the area by dry-farming impracticable. Considerable agricul- tural development has occurred since 1907. In the valley proper, underground water is usually found at less than fifty feet depth and often in quantities sufficient to make irrigation with pumped water practicable. A small acreage in the vicinity of Whitewater is re- claimed in this way. On the first mesas of the valley the water table is from 75 to 200 feet below the surface but the soil is often considered superior to the lower lands for dry-farming.* Farming conditions in San Simon Valley are comparable to those of Sulphur Spring Valley. Flowing artesian wells have been developed near San Simon ; and near Bowie artesian water has risen near enough to the surface to make pumping for irrigation feasible. The upper San Pedro Valley contains a large acreage of dry- farming lands similar to Sulphur Spring and San Simon Valleys. Intermittently successful dry-farming has been carried on for about ten years. In general the soils of the three valleys are loams and sandy loams. They are quite fertile and well supplied with lime. Water penetrates them readily and is quite efficiently retained. The soil samples of which the mechanical and chemical analyses are re- ported in Tables XVI and XIX are from the Sulphur Spring Valley Dry-farm near Cochise, and are representative of the soils of the three valleys. The bottom land soil reported in Tables XVI and XVII is a loam with a coarse textured stratum at the fifth foot, which hinders the rise of capillary moisture from below. The fine texture of the surface foot retards water penetration, especially that of light summer showers. For these reasons many farmers prefer the sandier mesa soils. The bottom lands contain fair quantities of nitrogen and humus in the first four feet, but the lower four feet are deficient in these materials. Potash, phosphoric acid, and lime are present in ample amounts. The lighter type of soil is repre- *For a detailed report on geologic and soil conditions in .'^ulphnr Siiring Val- ley, see Paper No. 320 U. S. Geological Survey, "Water Resources of the Sulphur Spring Valley." 528 Bulletin 84 sented by the sample of fine sandy loam from the Sulphur Spring Valley Dry-farm reported in Tables XVIII and XIX. It absorbs water readily and with cultivation retains moisture well. The large amount of lime is due to the presence of a calcareous hardpan. This soil is not so fertile as the bottom lands reported in Table XVII. Fig. 0. — San Simon Wash near .Solonionville, Ai'izona. TABLIv X\l. AII'CIIAXICAL ANALYSIS OF IIOTTOM SOIL, SULPHUR SPRING VALLLV DRY-FARM Very Sample Fina Coarse Medium Fino fine ; Silt Clay gravel .sand sand sand sand 1 % % % % % % % 1st foot 0.9 2.6 1.4 7A 13.6 48.3 25.7 2iid " .... 28 5.0 2.1 98 15.2 38.6 26.4 3rd " .... 4.5 9.5 4.0 16.5 17.1 28.8 19.8 4th " .... 6.8 103 Z.7 16 0 20.3 24.9 17.8 5th " .... 12.0 13.5 5.1 16 0 11.8 25.3 16.4 6th " .... 7.0 9.6 4.2 129 9.6 40.1 16.6 7th " .... 6.1 10.1 4.5 15 0 12.8 35.3 16.1 8th " .... 9.5 12.3 5.1 16 8 14.9 26.1 15.2 Average . . . 6.2 911 3.76 13.8 14.41 33.42 19.25 Principal Dry-Farming Regions 529 table XVII. CHEMICAL analysis OF BOTTOM SOIL, SULPHUR SPRING VALLEY DRY-FARM Acid in- soluble Pot- asli (K.O) Phos- plioric acid (PsOs) Limo (CaO) Nitro- gen (N) Humus Alkal 1 Composite sample Solu- ble solid:) dried at llO" C. Chlo- rides aj NaCl CaandMg sulphates and chlo- '■ides .as CaSOi 1st 4 feet 2nd 4 feet % 80.461 70.295 % .429 .465 % .121 .127 1.196 2.420 % .065 .023 % 1.280 0.510 0.136 0.100 % .008 .004 .087 .087 Avg. 8 feet 75.378 .447 .124 1.808 .044 .895 .118 .006 .087 TABLE XVIII. MECII.-VNICAL ANALYSIS OF LIGHTER TYPE OF SOIL, SULPIUTR SPRING VALLEY DRY-FARM Very Sample Fine Coarse Medium Fine fine Silt Clay gravel sand sand sand sand % <'/o % % % % % 1st foot 6.6 13.0 5.4 20.5 15.9 24.1 14.3 2nd " .... 11.0 11.9 4.6 16.4 13.9 25.0 17.0 3i-d '■ .... 11.1 15.1 5.4 18.6 13.8 23.9 12.1 4th " .... 9.5 14.9 6.6 24.8 14.6 19.4 10.2 5th " .... 12.4 14.3 5.9 21.6 13.2 21.9 10.6 6th " .... 10.8 . 9.3 2.9 10.1 10.8 35.0 21.1 7th " .... 5.4 8.1 3.5 13.1 13.9 38.1 17.7 8th " .... 4.8 9.7 4.3 13.5 14.0 32.8 20.8 Average . . . 895 12.03 4.82 17.32 13.76 27.52 15.47 TABLE XIX. CHEMICAL ANALYSIS OF LIGHTER TYPE OF SOIL, SULPHUR SPRING VALLEY DRY-F.\RM Acid In- soluble Pot- ash (K2O) Phos- phoric acid (P2O-.) Lime (CaO^ Nitro- gen (N) Humus Alkali Composite sample Solu- ble solid", dried at 110° C. Chlo- rides an NaCl CaandMg sulphates and chlo- rides as CaSOi 1st 4 feet 2nd 4 feet % 84.W4 59.831 % .487 .394 % .064 .083 2.048 13.062 7.555 ^0 .059 .020 % .5W .360 % .132 .180 % .004 .008 .006 % .011 Avg. 8 feet 72.362 .440 .073 .039 .450 .156 .005 INDIAN AGRICULTURE IN ARIZONA The Indians of Arizona, numbering from 40,000 to 45,000, have contributed very materially to agriculture in the State. Dry-land crop varieties, which have been grown by them for an indefinite period, are among the most promising ; and their cultural practices, with some modifications, are the bases of successful dry-farming in Arizona. The total area within the State at present set aside as Indian Reservations is about 17,500,000 acres. According to care- ful estimates it is possible to irrigate nearly one-quarter million acres of these lands, 109,992 acres now being under projects. The agricultural value of lands in the Reservations varies from worth- less to the best in the State. TRIBES AND THEIR CHARACTERISTICS The Indians of Arizona mostly belong to three families, the Piman, Yuman, and Athapascan, THE PIMAN FAMILY The Piman family is represented in Arizona by two tribes, lo- cated in the southern and southeastern parts of the State, the Pima and Papago. Tradition indicates that the Hopis of the north cen- tral part of Arizona formerly belonged to this family, but their dialect is distinctly Shoshonean, and their family relationship is questionable. Their tribal customs and agricultural practices cor- respond quite closely to those of the Pimas and Papagoes, however, and their contribution to the science of dry-farming has been as great. TJie Pima and Papago Tribes: Exploration of prehistoric ruins indicates that ancestors of the Pimas and Papagoes have been agri- cultural people for a great number of years. Corn, beans, wheat, chiles, and cotton have been their principal products ; though they now purchase most of their cotton supply. Among the promising crop varieties secured from them are tepary beans and Papago sweet corn, both of which have been bred up and standardized by the Arizona Agricultural Experiment Station. Pimas and Papagoes are particularly expert in the utilization of fioodwaters for supplemental irrigation. Of late years they have Indian Agkiculturk in Arizona 531 iL i b. gg ^ fa t 1 te^ ..^ ■^ JBM ■f ' to *:. V .. ^"^ 1 \~- '%:.. '• sv:??**! '■"'■"'; B*« !r*»- nii^^ w Hr.. J '> ' - Kr^^ Bi- , ~M i^' «i^- J r: ,-■.*" ■**?'■, - m L -_:_ ^^ K ^ ■ W i£^ 1 .^-^.- Fig. 10. — Papago floodwater, cUtth west of Coyote Mountain, Pima County, Arizona. mm J' ^ :>f-,*H. Fig. 11. — Papago well, showing method of water raising. 532 Bulletin 84 devoted considerable attention to stock raising and have developed an interesting system of range management. In winter they move all their belongings into the mountains and higher valleys. Here they stay vmtil well toward the end of the hot, dry spring and fore- summer. Shortly before the usual summer rains are expected, they return to their homes at the lower elevations and plant their crops of corn and beans, bringing them to maturity by means of occa- sional irrigations with floodwater. After harvesting their summer crops they return to their homes in the mountains where the range, which has been refreshed by summer rains, furnishes a maximum amount of forage for their livestock. Thus they are able to guard against famine because of their wise range management and by tak- ing immediate advantage of summer precipitation for dry-farming. The Ho pi Tribe: The Ilopi Indians (sometimes called Moqui) like the Pimas and Papagoes are peaceful, though anything but cowardly. They are comparatively short in stature, stockily built, and possessed of great physical endurance, excelling in their long distance races. Usually they live in villages ; while their fields are often several miles away. These Indians commonly make a run of ten or twelve miles to their fields, do a full day's work, and return home again in the evening without being much fatigued. Authen- tic reports indicate that occasionally they have run as far as one hundred miles in a day and at times they have been used to help catch wild horses, their efforts on foot being as valuable as those of white men on horseback in tiring wild range stock. As far back as their history is known, the Hopis have been agricultural people. They are essentially religious and are divided into a number of clans, the chief ceremonies of each clan being centered about agricultural occupations. The interesting and well- known "Snake Dance," for example, is a ceremony of the Snake Clan, assisted by the Antelope Clan, for the purpose of winning the favor of the rain gods in order that summer rains may be ample to insure them good crops of corn and beans. This ceremony is held about the middle of the summer rainy season. The "Flute Dance" is a ceremony of the Flute Clan for the purpose of winning the favor of the gods controlling the supply of subterranean water which ap- pears on the surface as springs. The principal crops of the Plopis are corn and beans ; and, like the Pimas and Papagoes, they have contributed several important Indian Ackiclltl-re in Arizona 533 varieties for dry-farming, including Hopi Lima, White Hopi, and Bates' beans, and White Hopi and Bkie Hopi corn. The agricultural implements of dry-farming Indians are few. While a number of them have plows, many have none. Virtually all cultivation is done with hoes, and planting with a long hardwood dibber. Oftentimes the land farmed is covered with a thin veneer of sand which acts as a mulch and renders comparatively little culti- vation necessary. At certain times of the year, often regardless of climatic conditions, they make their plantings, usually several inches deeper than varieties developed by white men will emerge from. In planting corn, the dibber is inserted twelve or fifteen inches deep and, as it is pulled out vertically, horizontal pressure is applied leaving a wedge shaped opening into which "a little boy's handful" or about twelve kernels are dropped. The seeds are covered loosely with soil, and the plants emerge with astonishing rapidity. The In- dians have long since learned to properly space their plants, and rarely seed too thickly. Weeds are kept down by hand labor, and the farming is quite intensive. When the season is especially dry and summer rains are de- layed, seeds are often inserted in balls of moist clay, and the masses thrust into the dry earth. The moisture in these balls of clay is usually sufficient to germinate the seeds and supply the young plants until rain comes. An advantage of two or three weeks' additional growing season is thus secured. Fruit growing is not practiced to a great extent among the Indians, though numerous peach orchards exist and oftentimes a fair quality of seedling fruit is produced. The trees grow in clumps and are never pruned or cultivated. The shifting of sand by wind oftentimes covers the tree trunks well up past the first forks of the limbs. Most of the orchards are planted in sandy and silt loams along washes and river bottoms where underground water exists near the surface. There are a few small irrigated orchards of ap- ples, pears, and plums as well as peaches. While the Piman family has contributed a number of very drought resistant varieties, natural selection must be given the credit. These Indians farm under extreme conditions, and destruc- tion of the unfit through a long period of time has left only drought resistant strains. Since "seed is seed" with Indians, varieties are badly mixed : for instance, in a field of supposedly white corn, white, 534 Bulletin 84 Fib. K -Chi-'inehm'\i Indian field on land subject to annual inundation by the Colorado River. , 4<» • M >-^-^'. ' •-.. ^.}-^-^'.- J»^.'W*'?I^^^ • -k*->jC-,^|N;_^ Fig. 13. -Yuma Indian field of corn and beans in a Colorado River slough after the annual flood. Indian Agriculture; in Arizona 535 dark blue, black, dee]) red, pink, yellow, and various combinations of the above may be found. The modified characters of their corn varieties are interesting. Collins* reports that Indian varieties of corn emerged when the seed were planted at a depth of thirty-two centimeters, while the greatest depth through which Boone County White could penetrate was twenty centimeters. He found that the combined length of coleoptyle and mesocotyl of Indian corn was thirty-five and one- half centimeters, while that of Boone County White was but fifteen and four-tenths centimeters. The thorough acclimatization of Indian varieties is further il- lustrated by the fact that tepary beans will form seed during the hottest part of the summer in the sub-tropical, irrigated valleys of Southern Arizona, while improved American varieties will fail un- less flowering takes place in cooler weather, and oftentimes even their leaves will drop off. THE YUM AN FAMILY The Yuman family includes the Maricopa, Mohave, Yuma, and Hualpai tribes. The Chemehuevis, a Shoshonean tribe, from long association with the Yuman family have adopted the agricultural customs of the Yumas. This family has done little to promote dry- farming but has become expert in farming lands subject to periodic flooding by the Colorado River. As the water recedes crops are planted in the muddy ground, and the conservation and utilization of soil moisture is sufficiently thorough to insure maturity of the crops. Because of the irregular periodicity of the Colorado floods, the Yumas have not been able to insure against famine as com- pletely as the dry-farming Indians of the Piman family. the; ATHAPASCAN FAMILY ' The strongest numerically and of least importance agricul- turally is the Athapascan family, including the Navajo and Apache tribes. Their subsistence has come from the chase and raids upon stores of neighboring Indian tribes and white people. In the early settlement of Arizona by Americans, some errors in management made the Apaches enemies constantly to be feared ; and, while the Navajos have ordinarily remained at peace, there 'Jour. Asric. Research, Vol. 1, No. 4, Jan., 1914, p. 993. 536 BuLIvlCTlN 84 has not existed the friendship that has been manifest between whites and the Piman family. Agricultural practices of the Apaches and Navajos are mostly confined to stock husbandry, the Navajos, particularly, raising a considerable number of sheep. These sheep are descended from stock brought in by the early Spaniards, and their ancestry possibly includes both Karakul and North African blood. They are quite tall, but stockily built, and, though the dressing percentage is low, the carcass is of good quality. The color is far from uniform, and, because of a high proportion of hairs, prices for the wool average one-quarter to one-half lower than for wool from Merino range stock. F.g. 14. — Apache vilUigc and farms, Northern Aiizona. In addition to sheep, goats, horses, turkeys, and some cattle are raised. The goats and cattle have recently been introduced, usually at the instigation of the United States Government. The horses are descended from original stock brought in by the early Spaniards, and, while very small, are quite tough and capable of considerable work both under the saddle and in the harness. Formerly large numbers of wild turkeys were found in various places in Arizona, and feathers from these birds have always been an important part Farming by Early White; Settlers ^^7 of ceremonial costumes. With the advance of civilization the wild turkeys were largely killed out, and, primarily to supply feathers rather than for any other purpose, the Indians recently have raised quite a number of domesticated turkeys. HOME LIFE OF THE INDIANS Tradition and old ceremonies are greatly cherished by the In- dians and carefully taught to each rising generation. Usually, they have an abiding faith in the "Great Spirit," and, while the concep- tion of the deity varies greatly with different tribes, they all are assured that he is watching over and helping them in their daily life. They often worship things of nature and utilize natural re- sources to the fullest extent. Their home life is simple, and usually they are contented, hon- est, and true to their friends. The women build and own most of the homes. Within some tribes marriage is an important ceremony while in others men and women live together by common consent until they become dissatisfied, whereupon the "husband" moves his belongings, usually consisting of a horse, saddle, bridle, and blanket, to a new abode. Ordinarily Indians do not care to take up the ways of white men, nor does it seem best that they should be forced to do so. FARMING BY EARLY WHITE SETTLERS Captain Weaver, a hunter and traveller along the Hassayampa River, cultivated a little garden patch about 1830, probably the first crop planted in Arizona by an American. His garden included melons, corn, and beans, the latter two being varieties which he secured from Indians. Early settlers who engaged in farming on Sonoita Creek, a tributary of the Santa Cruz River, included E. G. Pennington, Tom Gardner, William Kirkland, Tom Hughes, and John Cady, who located in the order named between 1857 and 1872. These pioneers principally grew corn, beans, and wheat with the use of occasional floodwaters, after the example of Pima and Papago Indians. In the fall of 1864, about seven years after the first attempts at farming on the Sonoita, Joseph Eagle and others put land in culti- vation in Skull Valley, an old battleground of the Indians so named because of the large number of human skeletons found there. In 538 BuivivETiN 84 the spring of 1865 they planted corn, beans, and other garden vege- tables, and in the succeeding fall harvested the first crops of pro- duce raised without irrigation by Americans in Arizona. About the same time other Americans settled in Williamson Valley, and a little later in Peeples' Valley. The main crop in these settlements was corn, the surplus being sold at Fort Whipple, near Prescott, for about twenty-five cents a pound. In the Del Rio and Little Chino Valleys, land was put in culti- vation in 1865 by George Bangheart and others. With irrigation these men produced mostly corn, root crops, garden vegetables, and potatoes. The first farming by white men in the Verde Valley probably began in 1866, at the junction of Clear Creek and the Rio Verde. With irrigation the rich, alluvial soil produced good crops of corn. Considerable trouble with Indians was experienced in all of the earlier settlements, especially in the Verde Valley. Because of reported possibilities for successful mining, the United States Government established a military post in 1863, at Del Rio, for the protection of prospectors against Indians. The following year this post was moved to Fort Whipple near Prescott. Most of the early settlers being interested in mining, only a few farmers persisted in following their vocation. High prices paid by miners and military authorities for farm produce, however, caused the establishment of a number of other ranches in Skull, William- son, Peeples', and Verde Valleys as the mining population grew. Attempts at dry-farming were made about 1870 in Navajo County, the early settlers following generally the example of Hopi Indians. In March, 1876, four colonies of Mormons arrived from Utah and settled on the Little Colorado River at Sunset, Brigham City, St. Joseph, and Obed. Their inability to cope successfully with the alkaline soil, and depredations by hostile Indians caused the settlements at Sunset, Brigham, and Obed to be abandoned. Most of the people removed to the vicinity of St. John, Woodrufif, Snowflake, and Heber. They were able to produce good crops of corn, beans, and potatoes at Heber without irrigation, but at the other settlements irrigation has been practiced from the begin- ning. About three hundred acres were farmed at Heber for four years when the settlement was almost entirely abandoned because of depredations by Indians and white cattle "rustlers." About this time Pinedale, Pinetop, Fort Apache, and Tuba City Farming by Eari.y White Settlers 539 were established. In 1875, William Mulligan located at Springer- ville where he cultivated about five hundred acres of land, his prin- cipal crop being barley, which was sold at Fort Apache for five cents a pound. In Yuma County, M. M. Redondo began farming in Laguna Valley in 1871, cultivating about 1200 acres. His principal crop was alfalfa which was sold for about seventy-five dollars a ton. Considerable irrigating water was taken from the Colorado River. At Quijotoa in Pinal County, farming, by means of supple- mental irrigation with floodwaters, is said to have been commenced as early as 1883. Manuel Ramerez began to farm fifty acres in 1887, at Picacho, in Pinal County by methods similar to those of the Indians. His success soon attracted other farmers, and a per- manent settlement was established. Dry-farming began at Moccasin on the "Arizona Strip" in 1903 when Jonathan Heaton planted about fifteen acres of rye, which yielded about twelve and one-half bushels per acre. An additional five acres yielded fifty bushels of wheat. While farming with floodwater was practiced at Fredonia as •early as 1884, no strict dry-farming was engaged in until 1910, when the Brown brothers and Owen Judd located on White Sage Flat, where they have produced as high as twenty-five bushels of wheat per acre. In 1881, Thomas McWilliam grew six to seven tons of potatoes per acre, selling them at twelve and one-half cents a pound. At the same time C. H. Shultz raised thirty bushels of corn per acre. A. H. Beasley grew good crops of potatoes and barley in 1884, selling liis products at three and two cents per pound, respectively. Little information is available about the earliest farming in Mohave County. In 1911, B. W. Hall planted eleven acres of wheat near Salome on the Parker cut-ofif. The wheat attained a height of four feet and yielded twelve tons of hay. While a few cattle ranches were established in the early eighties in Sulphur Spring and the upper San Pedro Valleys, little dry-farming was attempted until 1907. Despite a number of suc- cessful attempts at dry-farming by the early settlers of Arizona, no great interest was shown until about 1910, and the ensuing four years mark the greatest advance of the industry, when fairly ex- tensive developments occurred in various parts of the State. EXPERIMENTAL WORK IN DRY-FARMING In response to a need for data on dry-farming in Arizona, Experiment Station farms were established in 1908 at IMcNeal, in Sulphur Spring Valley ; in 1909 at Snowflake, in the Little Colorado Basin; and in 1911 near Prescott, in Yavapai County. The land on the McNeal and Snowflake farms was leased, but title was se- cured to the Prescott Dry-farm. In 1913 the Sulphur Spring Valley Dry-farm, a mile south of Cochise, was purchased and, since condi- tions were similar, the Experiment Station Farm at McNeal was discontinued. The lease on the Snowflake Dry-farm was given up July, 1916, and to date no other Experiment Station farm has been established in the vicinity. Detailed data obtained on the Snow- flake Dry-farm, the Prescott Dry-farm, and the Sulphur Spring Val- ley Dry-farm are given below, while Bulletin 70 of the Arizona Agricultural Experiment Station records the results obtained from operations on the McNeal Farm. SNOWFLAKE DRY-FARM Early in the fall of 1909, arrangements were made with Mr. W. J. Flake, Sr., of Snowflake, to use forty acres of his land, lying across Cottonwood Wash about one mile northwest of Snowflake, for experimental purposes. Part of this farm had been plowed several years before, but the sandy surface had been blown away and a fairly stiff clay subsoil exposed. The remainder of the farm was in sage brush. A layer of sand with a maximum depth of about seven inches covers much of the west thirty acres, and rocky spots occur frequently. The shallow soil of the Flake farm rendered moisture conserva- tion difficult, and in 1912 experimental work was discontinued and moved three miles up Cottonwood Wash to the farms of Mr. Don C. Smith and Mr. David Hancock where the soil was much deeper. The soil of the latter location is representative of a large area lying north of northeast of Holbrook and southeast of Woodruff. It is also typical of the valleys of 4500 to 5500 feet elevation lying be- tween St. Johns and Snowflake. Thirteen acres on the east end of the Flake farm were plowed and harrowed during September, 1909, following heavy rains. An additional seventeen acres were broken in January and February, Experimental Work ix Drv-Farmixc 541 1910, following light rains. The held was then harrowed lightly. After rains during the succeeding March it was again harrowed and a good seed bed prepared. The Smith property has been farmed intermittently since 1902. No effort had been made to control weeds for at least two years prior to the establishment of the Experiment Station farm. As a result, available soil moisture has been quite thoroughly exhausted, and persistent weeds seriousl_\- interfered with operations of the F.g. 15. — Wash on the Snowflake Diy-farm, showing uniformity of soil. first two years. The soil, about ten feet deep, is a very fertile fine sandv loam veneered with four or five inches of wind-deposited sandy soil from Cottonwood Wash, the high winds of spring caus- ing considerable soil movement. A part of the farm was plowed in the spring of 1912, and subsequently disced and cultivated with a knife weeder. The weeds persisted, how^ever, and about one-half of the field was plowed shallow in July. A second and deeper plowing was made during late August and early September, but the weeds still persisted to send up sprouts until they were killed back by frost late in September. In order to expose underground stems of certain weeds to winter freezing, another plowing was started in December, but was unfinished because of a heavy freeze. 542 Bulletin .84 A portion of the farm was harrowed twice in April, 1913, and the remainder three times. Five acres of the Hancock farm had been plowed in 1910, but the troublesome growth of weeds prevented preparation of a good seed bed for experimental cropping for more than a year. The re- maining fifteen acres were cleared of scattered trees and brush in 1913. The Hancock farm lies on a low, gently sloping hill and has a soil varying from four to ten feet in depth. Tillage of this farm, preparatory to the first experimental planting, was similar to that of the Smith farm. In the absence of reliable information, experiments on the Snowflake Dry-farm were planned in order to secure comparative data on crops and varieties best adapted, times of planting, rates of seeding, conservation and utilization of moisture, and economy of production. BEANS Table XX records the results of a variety test of beans for a six-year period ending in 1915. Most of the varieties tested are well known. They include a number grown for an indefinite period by the Indians, and two local strains. Little's and Bates', which, in the absence of more suitable identification, are given the names of the gentlemen from whom they were secured. Bean yields on the Flake farm were low in both 1910 and 1911. On the Hancock and Smith farms the highest yields in 1912 were only about 200 pounds per acre, and the beans were mostly destroyed by rabbits. High winds, drought and rabbits caused most varieties to fail in 1913, the only harvest being from plots of Bayou and Pink beans, and the largest yield was 116 pounds per acre. In 1914 effects of efforts directed against weeds began to be noticeable, and a more favorable season occurred with the result that yields of many varieties were high enough to insure some profit. The best showing was made by White and Red Hopi beans, while Colorado Pinto, a variety introduced in 1914, which has since been one of the best producers of the region, yielded 520 pounds per acre. In 1915, the entire crop was more satisfactory Experimental Work in Dry-Farming 543 TABLE XX. variety TEST OF BEANS, SNOWELAKE DRY-EARM I late 1 Date size Yield Y'ield Variety Field planted Stand har- of per per \'estefl plot plot acre 1910 '. f ' Acres P OHIlds Pounds Pink Flake ... 5-13 85 10-15 y. 25 1 50 White Tcpary hi 5-15 50 1/6 6 36 Yellow " *i 5-14 50 ib-i9 1/6 7 42 Striped Bunch. ... a 5-14 35 10-15 ^ 40 80 1911 White Tepary tl 4-21 50 10-10 Ya 4 16 H >4 11 4-25 10-22 Ya 8 32 Yellow Tepary 11 4-21 • • 1 1 . . . . .1 If u tl 6-8 I .... Ya 55 220 Pink ii 4-21 50 10-10 Ya 9/2 38 U a 11 ii 4-23 6-8 4-21 50 10-10 lo-io Ya Ya Ya 51 32 33 204 li 128 Striped Bunch 132 Bates' ii 4-23 10-10 /3 34 102 tt n 6-8 — Ya 61 244 1912 Bates' Hancock Smith . 5-24 ; 6-10 60 9-24 Ya 29 . . .2 116 White Tepary tt. 4* Hancock 5-24 , , .... , , . . .2 ti tl Smith . . 7-20 , , ... 4 , , . . .2 . . . Yellow " Hancock 5-29 .... . . . . .2 . . . »* " Smith . . 6-10 • • » t . . .2 . . . 4< ii " 7-20 ■ • . • , , . . .2 . . . li ti Hancock 7-24 .... ^ , 2 Pink •• 5-24 50 9-24 Ya 5\-^ 204 tt Smith . ^10 9-23 Ya 83 32 1913 Bayou Smith . . 11 • • ti 6-14 6-15 6-16 6-17 6-17 60 9-30 9-30 * Ya Ya 29 21 .1 1 1 116 Pink 84 Bates' ... White Tepary . . . it a it 6-4 . . . , . . .1 1914 Colorado Pinto... Hancock 7-7 90 10-10 Ya 1 30 520 Smith . 6-24 60 10-10 Ya 50 200 Pink li 6-24 50 10-11 Ya ] 20 480 Bayou ii 6-24 75 10-11 Ya 1 32 528 Trammell Hancock ^24 75 10-15 Ya 105 420 Little's li Smith . . 7-7 4-28 60 9-i9 Ya ■ Ya 4 60"' Lady Washington . 240 a t* 11 6-24 90 10-5 Ya ] 08 432 if Ik Hancock 7-7 90 10-10 Ya 60 240 White Tepary li (y-26 . , 5 Bates' Smith . . 6-4 60 10-4 H ^ [13 452 Hopi Lima ■ii 6-2 Ya 5 Yellow Hopi (( 6-2 60 10-4 Ya 1 00 400 White " 11 6-2 75 10-4 Ya 180 720 Red " ii 6-2 70 10-4 Ya 150 600 1915 Lady Washington. Smith . . 5-3 75 10-9 Ya : 100 800 1. (1 11 5-26 75 10-9 Ya ' ?05 820 « 11 11 6-19 75 10-9 Ya 146 584 11 11 Hancock 1 6-24 10-9 Ya 60 240 1 — Failed. 2 — De.stroyed by rabbits. Failed to mature. 3 — Injured by rabbits. 4 — Immature. 5- 544 Bulletin 84 TABLE XX. — Continued Variety 1915— Continued Little's Colorado Pinto. . .. Red Hopi Valentine Bayou Pink Hopi Lima Casa Grande Aztec Yellow Hopi Black Teparv Yellow " White " White '■ Field Date planter! Hancock Smith Hancock 6-2 6-2 6-2 6-2 6-2 5-8 5-19 5-19 20 28 21 21 21 17 stand Date har- vested % 70 70 60 65 70 80 50 65 75 50 80 80 85 80 10-15 10-15 10-15 10-15 10-15 10-9 ic^-'io 10-20 10-15 10-1 10-1 10-1 10-15 Sizo of plot Acres 1/10 1/10 'A 'A A A 1/40 1/40 1/80 /4 A 1/ Yield per plot Poitinis 25 45 60 60 116 150 205 60 240 280 275 125 Yield per acre Pou n ds 250 450 240 240 464 600 800 240 960 1120 1100 500 5 — Failed to mature. 6 — De.stroyed by thrips. Fig. 16. — Dent corn and beans, Snovvflake L^ry-farni. than in any previous year. The yield of about half of the varieties was sufficient to insure profit. Black, Yellow and White teparies ExpKRiMKXTAL Work ix Drv-Farmixg 545 procfuced from 960 to 1120 pounds per acre. Yields from plots of Lady Washington beans were satisfactory and the desirability of Colorado Pintos and Bayous was again demonstrated. Hopi Limas, which have proven interesting on all of the Arizona Agricultural Experiment Station dry-farms, again failed to mature. The variety test of beans is summarized in Table XXI. An- nual yields of each variety are calculated as the average of yields of all plots of that variety. The adaptability of Teparies, Lady Washington, Colorado Pinto, and Bayou beans is shown. TABLE XXI. SUMMARY OP VARIETY TEST OF 1 L^ANS, SNOWI^LAKE DRY-FARM Yield per acre Variety 1910 19H 1912 1913 1 VjW i 1915 Average Po 11 luU Pounds Pounds Pounds Pounds 1 PoUJids White Tepary. .. 36 24 . . . . . . 800 143 Yellow " 42 110 . ■ > . . . 1120 212 Black " • • • . • . . . . 960 960 Lady Washington . . . 304 611 457 Bates' 173 116 . . . 452 .... 185 Pink 50 123 118 42 480 520 600 450 235 Colorado Pinto . . 485 Red Hopi . . . 600 240 420 White Hopi .720 720 Hopi Lima . . . Bayou 116 528 464 369 Valentine • • • 200 240 220 Casa Grande 800 800 Striped Buncli. .. . 80 132. . . . .... 106 Trammell . • • 420 420 Little's 250 125 Aztec 2 Yellow Hopi 400 240 320 1— Failed to mature. 2— Blooms destroyed by thrips. To determine the most favorable date on which to plant beans, a test which included the planting of one variety each year on various dates, was begun in 1912 and continued in 1914 and 1915. The Bates' variety was used in 1912, having been planted on dates- ranging -from May 24 to July 10. See Table XXII. The earliest planting was most successful, later plantings failing to mature. In 1914, Lady Washington beans were planted, the plot seeded June 24 yielding highest. Lady Washington beans were again used in 1915, plots seeded in May producing best results. From the data of Table XXII and from general observations it appears that beans in the Snowflake vicinity should be planted in May; 546 BULI^ETIN 84 TABLlv XXII. riKAXS; TIME OF PLANTIXG TEST, SNOWFLAKE DRY-f-ARM Variety Date planted Yield per acre Remarks Pounds 1912 Bates S-24 5-25 6-25 7-10 116 48 Beans half matured ti No beans matured •• Pods just setting 1914 Lady Washington.... 4-28 240 " 6-24 424 (t a 7-7 240 1915 Lady Washington .... 5-3 800 •' 5-26 820 i( n 6-19 584 il ti ^24 240 June and July plantings being oftentimes too late to mature and April seedings usually too early. It is obvious that because of the difference in the leaf area of bean varieties a corresponding difference in spacing the plants must be made. Experience indicates that rows of kidney beans and teparies should be not less than 36 inches apart, and that the dis- tance between the plants in the row should be from twelve to eighteen inches. Planted in this manner, from six to nine pounds of seed per acre must be provided for such varieties as Pink, Bates', and Lady Washington, while, of the smaller varieties, such as Tepary and White Navy, from five to seven pounds are required. Where soil moisture conditions are favorable it is desirable to plant beans with an ordinary planter. However, if a sub-surface crust appears in the soil or if soil moisture is low, planting in a lister furrow is to be preferred. Beans must be planted well into moist soil, if satisfactory germination is to be secured, the optimum depth being usually from three to six inchees. Where precipitation is light and where moisture dissipating conditions are particularly eft'ective, as in the Snowflake vicinity, very careful attention should be given to cultivation, which should be continued persistently until the flowers are setting and the plants have begun to spread to a considerable extent. Especially is it necessary that weeds be destroyed as quickly as possible after their appearance. Several makes of bean hearvesters are sold by implement houses. A home-made harvester, however, consisting of a culti- Expe;rime;ntal Work in Dry-Farming 547 vator, with knives so placed that they will cut off the plants just beneath the surface of the ground, is very satisfactory. The vines should be cut and piled when they are toughened by dew, a hay rake often being satisfactory for bunching. Threshing may be done by a grain separator which has the speed of the cylinder much reduced and the concaves removed. Many beans are apt to be broken, but usually not enough to justify the trouble and expense of securing a regular bean separator. Table XXIII is a financial statement of costs and returns from growing an acre of beans at the Snowflake Dry-farm in 1915. It will be noted that the yield per acre, 500 pounds, while not high, is sufficient to return a fair profit. table; XXIII. RI5TURNS FROM AN ACRE OF BEANS, SNOWFLAKE DRY-EAR M, 1915 Production co.sts per acre \ Taxes Interest Plowing One double disking. Two harrowings . . . Planting Four cultivations. . . Hoeing Harvesting Seed Threshing Total Dollars .75 .50 2.00 .50 .30 .25 .50 1.20 1.25 .50 1.00 875 Yield per acre Pounds 500 Gross returns per acre Dollars 20.00 Net gain Dollars 11.25 CORN Eight varieties of corn were planted in 1910 (see Table XXIV), and, as indicated by the table, most plots were replanted. No seed was produced, but the best yield was obtained from plots of Red Dent. In 1911, seed was produced on most plots, the best yields being obtained from Yellow Dent and Australian White Flint. Four plots received an irrigation of floodwater. In 1912, only Australian White Flint and Yellow Dent were grown, and the yields were small. One plot of Australian White Flint was destroyed because of soil movement by wind. 548 Bulletin 84 Nine varieties were grown in 1913, but, because of drought, no grain was produced except in a plot of Yellow Dent. The best yields were obtained from Plickory King, and a variety obtained from the Pima Indians. In 1914, the season was much more favorable than in 1913, and a fair yield of ear corn was obtained from plots of White Flint, Blue Hopi, and Minnesota King. The best yield of forage was produced on a plot of Hickory King. In 1915, 2133 pounds of ear corn per acre were produced on a small plot of White Hopi, and 2000 pounds of ear corn per acre on a plot of Australian White Flint. In general, yields were quite satisfactory and represent profitable returns from corn grown in the Snowflake vicinity for ensilage purposes. Fig. 17. — Corn, Snowflake Dry-farm, 1911. Exi'i-KiMi'XTAL Work ix I)in-l<\\UMiX( 549 m.imd Fig. 18. — White Dent corn, Sinnvflake Iir\-fann. August 17, li)]2. ,^i*.^i>*€i- -f mc Fig. 19. — Corn, Snowflake Dry-farm. June 22, 1915. I'lot on left seeded May 10; plot on right seeded three weeks later. 550 Bulletin 84 m u u (D n 2 .So. w a 2 4/ = O •O -OO -O • \0 • -rt- VO O ■CM • Tj- CO ■ -^ -o ■czO\rr> O^O OO o Tl- lO (NJ ^— * • (VJ (V) - •— ^ ^ 6 : C^ • 1 • o 6 :ci : ■.66c^6c^6 ci^ ■.c^.c\ ■.c\ • T— » . f— < *— « »— 1 ,— H r— I ,— 1 »-H y—t • r—i r—t •a c ^ o O lO • O o • lO Cirj . - o • o . o • o • ■ o o ■ o 4-* 00 iri \o • ir> to •r^ u-5 CO • . U-) . iTi . \D • kO • ■\0\Cl • o w CV1(V1 4. a win Uh 2 ^ c Q c w O .S to c in 3 < bo c S 1.1 O 4-t •—4 c . a o Ph .S. bo o c o X > to I-. aj •*-» 3 m >> § . 1 I- , Experimental Work in Dry-Farming 551 -a ' m < ■ e oo NO "^ CO CO ■ o • o •NO • CO o o •o ■ NO • O NOOO • NO in c^i .^o . ^o o o o c o hK— ' ^Tt- 'tf- -^^ ^ XT ^ •—1 cot^"^C0C0CO c m b3 C D, 1) lO tT 0\ ^ O o m CO CM 'M <^ C-) IM CO CM ON i oociooNON CJN fv. 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CO • vo--- .••^ro----M-^ ■•-c O ....^_ .pq 1, 0 o • o o -as -r- oo o • O . . . • • lo ■ 00 * ^ *— ' r~) • •■••• .\o • -O -O • -Cg^o O • n \0 -O • -C^l -VO • -cou-j VO • ■*-) C^) • • CX) • • ^H .CO - • t^ (Nl ^H . 7J — tH 05 C o • • •■ O • • • -OO ■ • -1- • co----Tro •• >-v Tj- • \0 ■ ■ ■ -Tj-rJ- ■ • •0 O c 3 u o 0) ■^ • C CO O (V) ■* OC lO CVJ ■ . • . VO -* CO CO CO vo -O 0^ • ■ • • a > VO • o t^ • 00 On rv] 00 (^ CO CO (^^ • - • ■ . CM ,_ ^^ ^^ ^^ (M . . . . u ^ 02 r-t 05 f: . • • • O • • p. ■rf : : : : : :: :^ :::::: : : : ■d O (p u> h o ■M • [ o o rv) r^ t^ --/X rH 05 c . o o t4 . o <^i t-H .... ... ,-H . . o ' bl (1> t^ • > o • CO---- •O"^'— ' •• o ■^ • On (NOOVO m. rsj • — ■*— t-( C5 c r^ • \o 00 ri • T-H CO VO o u 01 O'O rn ■* O NO O "^ On no . . C^lC^l -^ CO •* O ON CO • . O m ' ' '* c Lh o o CJ - ; i ^1 C u -t- -i-i 1> King ellow > .2 bj Silver Dent . 's Red 1 Dakc ory Ki ly But w Den m o bD can B d Hop esota ■ado Y nt ... a, O X - |fe i ^-sS o^-"^ §^ a^.B s.ii|.E|p;s ^ U< t— ^C^ W^ Xm> < PhP- <5<: p: ^ U ^ 1 ExpUrimextal Work ix Dry-Farmixg 553 As indicated in Table XXIV, early maturing and small grow- ing corns are safest in the Snowflake vicinity. In the timber belt, where the rains are apt to be more plentiful, some of the larger im- proved American varieties may be successfully grown for silage, but best results will probably be obtained from the larger Indian varieties and the smaller and earlier eastern strains. Table XXV summarizes the variety test of corn on the Snow- flake Dry-farm. Annual yields represent the average of all plots of a given variety. for the year specified. To determine the optimum spacing of corn plants (see Table XXVI), six plots of White Flint were planted in 1913 in rows thirty-six inches apart and in hills from two to thirty-six inches apart. Because of the unfavorable condition of the season the data are not especially valuable. TABLE XXVI. corn ; SPACING TEST, SNOWELAKE DRY-EARM, 1913 Variety Field Size of plot Ddstance between rows LHstancc between hills Fodder per plot Fodder per acre White Flint.... Smith Acres 1/20 1/20 1/20 1/20 1/20 1/20 Inches 36 36 36 36 36 36 Inches 2 4 6 12 24 36 Pounds 46 43 38 36 25 30 Pounds 902 860 760 720 500 600 POTATOES Potatoes were first grown on the Snowflake Dry-farm in 1910 (see Table XXVII), when one plot each of Early Ohio and Early Rose were planted. Both plots were so injured by shifting soil that it was necessary to replant June 29. The quality of the small yield, which was insufficient to replace the seed tubers planted, was inferior. No potatoes were grown in 1911 or 1912, but in 1913 four vari- eties, all of which failed because of drought, were planted in the Smith field. In 1914, five varieties, three standard and two local, were grown, the best results being obtained from Peachblow, the two local strains comingi^econd and third, respectively. Yields in 1914 were sufficient to indicate that potato growing may be profitable. 554 BuiwivKTiN 84 TAHLE XXVII. VARIETY TEST OF POTATOES, SNOWFAKE DRY-FARM Variety 1910 Early Ohio . . . . , Early Rose 1913 White Star Early Ohio Snowflake Burbank 1914 Early Ohio ; . . . . Wrencher's Sur- prise Blue Victor Snowflake Peachblow 1915 Vermont Gold Coin Mammoth Pearl. Showlow Peachblow Lakeside Blue Victor Early Ohio Field Flake Smith Date planted 5-16 5-16 6-3 6-4 6-6 6-5 5-20 5-20 5-20 5-20 5-20 5-13 5-13 5-13 5-13 5-13 5-13 5-10 5-10 5-10 5-10 5-10 5-10 5-10 5-10 stand 7c 30 30 80 80 80 80 85 80 60 80 30 50 40 70 70 70 70 70 70 70 70 Date harvested 11-3 11-3 10-25 0-25 0-25 0-25 0-25 1-13 1-13 1-13 1-13 1-13 1-13 1-13 1-13 1-13 1-13 1-13 1-13 1-13 1-13 Size of plot Acres 3/40 3/40 1/40 3/40 Ya Va Ya Ya Ya 3/40 1/40 3/40 1/40 1/40 2/40 1/40 1/40 1/40 1/40 1/40 1/40 1/40 1/40 Yield per plot Pounds 1201 701 660 1000 550 1060 1400 800 180 654 176 165 80 110 107 100 96 65 102 120 114 Y'i-eld per acre I^oiinds 240 140 2640 4000 2200 4240 5600 10664 7200 8720 7040 6600 1600 4400 4280 4000 3840 2600 4080 480O 4560 1— Replanted Jure 29. TABLE XXVIII. SUMMARY OF VARIETY TEST OF POTATOES, SNOWFEAKE DRY-FARM Variety Yield per acre 1910 1913 1914 1915 Average Early Ohio Pounds 240 140 Pounds Pounds 2640 "4240 '4000 2200 5600 . . . ^ Pounds 4070 'ieoo 7040 10664 7200 8720 6600 Pounds 1737 Early Rose 140 White Star Snowflake Burbank VVrencher's Surprise Blue Victor Peachblow 2120 4000 1900 6320 Vermont Gold Coin Mammoth Pearl Showlow Lakeside 10%4 7200 8720 6600 5 • a fi 4-23 10-10 v^ 2054 4108 a 4-25 60 10-1 % 116 464 1912 Pink Kafir Smith 6-10 9-25 Va 516 2064 Hancock 5-20 10-14 % 1205 4820 White Kafir.... Smith 6-10 9-26 Va 87 348 « « Hancock 5-20 10-14 Va 640 2560 Dwarf Milo. . . . Smith 6-10 9-25 3/20 305 2033 " « (( 6-25 9-25 I/IO 1 Hancock 5-22 9-21 Va 1190 4760 Standard Milo. . (( 5-22 10-24 Va 910 3640 Broom corn Smith 4-27 9-26 Va 1110 4440 Hancock 5-22 10-14 Va 510 2040 Shallu Smith 6-11 9 26 Va 170 680 (( Hancock 5 '^7 9 26 /A Va 436 1744 109^ (( Smith 6-10 9-26 /A Va 273 Experimental Work in Dry-Farming TABLE XXXII — Continued 561 Variety 1913 Feterita Milo White Kafir.... Broom corn, Field Smith Black -hulled White Kafir.. Black - hulled White Kafir.. 1914 Feterita Dwarf Milo 1915 White Kafir.... Feterita Shallu Dwarf Milo. . . . Smith Smith Hancock it Smith Date planted Stand 6-14 6-14 6-14 6-14 6-2 6-3 6-3 6-3 6-1 5-1 5-26 6-17 6-7 5-3 5-26 6-19 % 60 85 70 5 75 95 80 75 Date har- vested 10-15 lO-l 10-10 io^io 9-27 9-27 9-27 Size of plot Fodder per plot Acres Pounds •• 1 1 1 Va 72, 1 1 . . 1 . . 1 'A 54 16602 1000 54 54 54 3/40 3/40 3/40 2450 1 "soo 4153 3223 2753 Fodder per acre Pounds 292 6640 4000 9800 3200 5533 4293 3666 1 — Failed. 2— Immature. 3 — Calculated from green weight. Rye: A plot of spring rye, planted in the spring of 1915, pro- duced at the rate of 900 pounds of grain per acre. It is likely that rye will become popular as a hay crop on dry-farms of the region. SORGHUMS Grain Sorghums: Three varieties of grain sorghums were planted in 1910 on the Flake farm (see Table XXXII), the best yield being produced by Broom Corn. Of the sorghums adapted for feeding. Standard Milo was most successful. In 1911, Broom corn again yielded highest, Black-hulled White Kafir second. TABLE XXXIII. SUMMARY OF VARIETY TEST OF GRAIN SORGHUMS, SNOWFLAKE DRY-FARM Yield of fodder per acre Variety 1910 1911 1912 1913 1914 1915 Average Pounds Pounds Pounds Pounds Pounds Pounds Founds Standard Milo... 767 1900 3640 .... .... 1577 White Kafir 486 1454 146 .... 9800 2972 Broom corn 1180 2497 3240 .... .... .... 1729 Black-hulled White Kafir.... 1919 .... .... 959 Pink Kafir 3442 < • • • .... 3442 Dwarf Milo 2264 ■ • > • 4000 4497 3587 Shallu 1172 .... 6640 3200 2186 Feterita 2213 562 Bulletin 84 Several varieties were planted in 1912, the best yields being from Pink Kafir, Dwarf Milo, and Broom corn. Because of drought all plots failed in 1913, and no crop was harvested except on plot of White Kafir which yielded less than 300 pounds of fodder per acre. In 1914, the only grain sorghums grown were Feterita and Dwarf Milo, the latter producing 1600 pounds of seed per acre, the first sorghum seed produced on the Snowflake Dry-farm. Best yields of the entire test were secured in 1915, a plot of White Kafir yielding 9800 pounds of dry fodder, while profitable results were obtained from Dwarf Milo and Shallu. TABLE xxxiv. VARIETY TEST OF FORAGE SORGHUMS, SNOWFLAKE DRY-FARM Variety Field Date planted Stand Date har- vested Size Fo of ] plot I dder Fcvc 3er p )lot ac ider er ;re 1910 Amber 1911 Amber it Flake Flake a Smith Hancock Hancock Smith tt (t • . . • 3rd " 7.16 4.37 5.39 5.66 4th " 4.54 5th " 6.29 • • < • Average 7.79 6.43 5.45 4.77 5.04 6.69 Avg.all sam- ples, 6.03 Sept. 29 1st foot 5.98 8.40 5.42 4.11 7.42 5.76 2nd " 6.61 4.50 3.80 4.26 10.02 3rd " 9.08 6.80 3.80 3.83 7.50 4th " 6.22 4.12 8.08 Average 7.09 7.27 4.46 3.96 5.17 7.84 Avg.all sam- ples, 5.96 1911 May 23 1st foot 8.15 8.16 8.80 11.05 14.81 12.25 12.33 18.03 2nd " 8.39 6.03 6.41 12.93 10.74 16.52 13.60 14.20 3rd " 3.47 7.54 Average 8.27 7.10 6.23 11.99 11.03 14,39 12.97 16.11 Avg. al» sam- ples. 11.01 Aug. 31 1st foot 6.94 8.43 7.63 9.47 9.21 15.45 10.10 2nd " 8.46 9.05 9.29 10.20 13.28 11.77 3rd " 9.70 8.65 12.19 14.73 Average 7.70 • • . • 9.06 7.63 9.14 10.53 14.49 10.93 Avg.all sam- ples, 9.93 1912 Mav 23 1st foot 8.41 15.10 13.30 14.27 12.18 9.12 10.33 Smith and 2nd " 13.11 18.10 16.41 11.23 13.02 15.41 16.21 Hancock 3rd " 15.22 16.98 17.55 14.38 10.91 15.82 16.63 Fields 4th " 15.24 20.92 12.25 17.65 15.04 5th " 21.16 22.24 15.45 13.57 15.03 6th " 19.83 20.91 18.33 14.46 19.51 7th " 20.32 8th " 19.77 9th " 20.53 Average 12.25 16.73 17.25 17.32 15.86- 14.34 15.46 Avg. all sam- ples. 15.60 1913 1st foot 10.30 8.60 6.90 11.00 10.00 8.40 13.30 Aug. 1 2nd " 6.20 10.90 12.30 12.90 12.70 9.60 17.60 3rd " 7.30 11.50 12.40 7.60 12.70 8.80 17.60 4th " 5.00 10.10 18.40 14.00 18.60 8.10 15.10 5th " 18.50 5.70 17.30 11.60 18.60 6th " 19.70 17.20 17.70 15.20 19.60 7h " 22.20 15.00 19.40 16.20 17.90 8th " 21.30 15.90 21.70 17.20 21.30 Average 7.20 10.27 16.46 12.41 16.26 U.89 17.62 Avg.all sam- ples, 13.16 •From adjoining virgin land. TABLE xij — Continued Sample t&ken Depth of Hole 1 Hole 2 Hole 3 Hole 4 Hole 5 Hol« Hole 7* Hole 8* sample % 7c % % 7o % % ?c Dec. 12 1st foot 12.6 14.2 12.2 13.9 13.8 12.1 13.1 12.8 2nd " 9.0 16.4 13.5 14.8 12.3 8.5 10.9 11.7 3rd " 7.5 17.3 15.4 11.0 11.5 9.0 15.0 4th " 8.2 11.8 \3.9 13.8 14.9 12.0 16.3 5th " 16.8 11.0 26".6' 14.7 16.2 15.7 15.6 13.5 6th " 21.9 13.5 18.4 20.3 17.9 16.3 11.7 11.9 7th " 19.6 13.7 14.7 24.0 15.5 18.5 10.3 12.3 8th " 17.6 12.9 17.3 16.1 16.4 10.2 Average 14.1 13.8 15.9 16.9" 14.6 14.2 11.7 13.'4' Avg.ai* sam- ples, 14.3 1914 July 1 1st foot 3.7 6.2 4.4 4.5 7.5 8.5 6.8 6.6 2nd " 6.6 14.8 13.9 12.7 11.8 12.7 16.0 10.8 3rd " 8.6 11.7 16.8 10.6 14.5 18,4 11.4 4th " 6.5 8.2 18.3' 16.7 18.6 16,4 17.3 13.7 5th " 6.4 11.6 15.6 7.9 17.2 17.3 14.8 16.8 6th " 10.0 16.5 19.6 15.9 18.0 19.4 19.0 7th " 6.4 18.7 21.0 18.3 13.5 20.9 13.4 8th " 21.3 21.0 16.4 15.8 21.4 11.0 Average ' 6.0 13.6 16.3 13.6 14.1 16.4 14.6 12.8 Avg. all sam- ples, 13.4 Oct. 20 1st foot 10.5 21.7 12.4 17.5 15.3 15.5 15.2 13.7 2nd " 5.1 14.5 19.6 16.6 12.6 13.3 12.5 10.6 3rd " 6.9 10.8 21.3 16.8 12.2 17.0 15.9 11.4 4th " 6.2 8.5 18.0 15.6 19.0 19.5 14.3 11.0 5th " , . , , 13.7 18.5 21.9 18.0 16.5 14.4 14.7 6th " • > < • 19.0 23.3 18.2 17.7 21.2 14.7 14.3 7th " » • . • 20.0 22.0 16.9 14.9 21.3 15.5 16.5 8th " 19.7 22.6 15.8 16.0 23.3 19.2 Average 7.2 16.0 19.7 17.4 15.7 18.4 15,2 13.2 Avg. an sam- ples, 15.3 1915 July 1 1st foot 6.4 8.9 5.7 5.4 7.9 12.1 11.3 9.4 2nd " 7.8 15.5 8,7 17.6 1?? 14.2 15,0 12.9 3rd " 11.6 17.5 20 0 8.2 15.2 18.1 15,0 14.5 4th " 9.2 13.4 17.7 25.1 19.1 19.5 17,6 16.3 5th " .... 17.1 17.4 10.7 18.5 19.6 13,6 20.0 6th " 12.6 21.8 16.5 18.3 23.0 15.1 18.4 7th " 13.5 21.2 17.5 17.4 24.7 16,2 20.2 8th " 23.8 19.2 128 18.9 25.7 19,2 18.1 Average 8.7 15.3 16.4 14.2 15.9 19.6 15,4 16.2 Avg. aM sam- ples, 15.2 » Oct. 20 1st foot 5.6 9.9 11.6 10.9 10.6 12.6 7,2 5.6 2nd " 6.5 15.6 11.35 11.0 "10.8 13.4 13.6 8.2 3rd " 9.4 136 18.9 13.9 12.3 18.8 9.1 4th " 7.8 12.0 18.7 18.5 17.6 20.2 i45 11.6 5th " ... 15.8 15 1 170 17.5 19.2 13.7 18.1 6th " 19.3 15.7 17.0 15 2 24 0 14.5 15.4 7th " 20 3 1«1 21 6 17.4 25.3 16.3 19.4 8th " 18 2 13.9 20.4 17,1 22.8 18,6 20.8 Average 7.3 15.6 15.4 16.3 14.8 19,5 14,1 13.5 Avg. all sam- ples, 14.5 *From adjoining virgin land. 570 Bulletin 84 moisture storage To determine the variation in the moisture content of the soil, series of samples were analyzed in spring and fall each year the farm was operated. Borings were located at various representa- tive places on the farm and eight-ounce soil samples were taken to a depth of eight feet where possible. The results are given in Table XLI. Samples in 1910 and 1911 were taken from the Flake field, and for the remainder of the period from the Smith and Hancock fields. The intention was at all times to take samples in sum- r.ier immediately prior to the summer rains, and in fall when the land \\-as driest. A striking feature of the data in Table XLI is the low moisture content of the first foot of soil in late spring and early summer. Moisture dissipating forces are particularly active in spring and special care should be exercised to conserve all the moisture pos- sible. A finely pulverized mulch in fall is undesirable, since it prevents ready percolation of water; while if the surface is rough, deeper penetration is secured, and a greater percentage of water re- mains in the ground. It has been observed that a surface crust forms in June even under mulches four to six inches deep. This crust is more pronounced in heavy soil but is evident in all types. The need of conserving sufficient moisture from winter precipitation to germinate and maintain seedings made prior to the formation of the sub-surface crust is manifest. PRESCOTT DRY-FARM In the summer of 1911, after several examination trips had been made over the promising agricultural districts of the vicinity, the Prescott Dry-farm was established seven miles north of Prescott and one and one-half miles north of P. & E. Junction, on the Santa Fe, Prescott & Phoenix Railroad.* The farm includes three soil types characteristic of the more important valleys of the region. It contains both level and steep lands, and aft'ords opportunity for irri- gation with diverted floodwater. Establishment of the Prescott Dry-farm was made possible by cooperation of the Prescott Chamber of Commerce, through which business men of Prescott subscribed $2000; the Santa Fe, Prescott & Phoenix Railroad, which, through its general manager, Mr. W. A. Drake, subscribed $2000; and a $500 appropriation subscribed ♦For map of Prescott Dry-farm see Twenty-eiRhth Ann. Rept. Ariz. Agric. Expt. Sta., p. 399. Expe;rimkntal Work in Dry-Farming 571 through Governor R. E. Sloan of the Territory of Arizona. The operation of the farm since has been financed by appropriations from the State Legislature. There were no dry-farms in the immediate vicinity, and the production of crops without irrigation was an untried experiment. The southeast corner of the Prescott Dry-farm is the highest point on the place, being 5012 feet above sea-level, and the north- west corner, on Granite Creek, is the lowest, with an elevation of 4946 feet. The farm is cut diagonally into two nearly equal areas by a wash which originates in hills directly to the east. This wash is dry except in times of heavy storms when often it carries con- siderable water. The higher parts of the farm were covered with a native growth of scrub oak. Other areas supported a fair growth of native grasses including white and blue grama, six weeks, bufifalo, and bunch grasses. Approximately sixty acres are under cultivation. Knolls of the farm expose a red, compact loam which, when dry, is very hard and, when wet, very sticky. This soil contains a relatively large amount of fine clay particles. In places, this soil is mixed with coarse gravel. Soil of the grassy flats of intermediate eleva- tion is darker colored and contains a high percentage of very fine sand particles. The bottom land is fertile, dark loam containing liberal amounts of organic matter and lying immediately adjacent to the creek. For mechanical and chemical analyses see Table X to XIII inclusive. From its establishment vintil the present time, efforts on the Prescott Dry-farm have been mostly directed towards finding out the best adapted varieties of agricultural crops, the most practicable cultural operations, and a safe and reasonably dependable system of farm management. ALFALFA Three plots of alfalfa were planted in 1912 (see Table XLII), one of which was w^inter killed, one was destroyed by drought and rodents, and the third grew to a height of three inches before the cold weather of winter. Growth was renewed the following spring but the alfalfa was killed by drought in June, 1913. In 1913, twelve plots of Grimm, Peruvian, Algerian, Arabian, and Provence alfalfa were planted from seed produced by dry-farming in various localities 572 Bulletin 84 TABLE XLH. VARIETY TEST OF ALEALFA, PRESCOTT DRY FARM i Date Size of Variety planted plot Remarks 1912 Arizona Common 8-4 Killed by drought and rodents Turkestan 8^ 1/6 Grew 3 inches until hit by frost, came out in spring and was killed by drought in June Kansas Winter killed 1913 1 Montana Dry Land. . . 1 6-23 % Growth of 6 inches Nebraska " " . . . : 6-23 % " 6 ' Arabian No. 26461 . . 7-8 1/40 " 6 ' Provence No. 24602. 7-8 1/40 " 6 ' Peruvian No. 29353.. 7-8 " 6 ' Algerian No. 12846.. 7-8 " 6 ' Arizona Peruvian... 7-8 1/40 " 6 ' Turkestan 7-8 1/40 " 6 Minnesota Grimm. . . 7-8 1/40 " 12 ' Arizona Common. . . . 7-8 1/40 " 6 ' Northern 7-8 1/40 " 6 ' Idalio Dry Land .... 7-8 % " 6 ' 1914 Growth of 6 to 8 inches 1915 Growth of 6 to 8 inches 1916 Plowed under Fig. 27. — Beans, Prescott Dry-farm. Expe;rime;ntal Work in Dry-Farming 573 TARLR XLIII. VARIETY TEST OE REANS, PRESCOTT DRY-EARM Variety jjaie Stand planted 1912 Tepary ^t it it Lima Bates' Lady Washington.... ti a it a Pink '.'.'.'. Wax 1913 Bates' ti Colorado Pinto Lady Washington.... Little's Aztec Lima Tepary Black Wax Indian Yellow Burpee's Strinaless. . . tt tt Pink Bayou 1914 Red Hopi White Hopi Yellow Hppi Hopi Lima Colorado Pinto II II Tepary it Black Wax Spotted Stringless. . . . Burpee's Stringless. . . Lady Washington .... X II Bates' tt Hanson Bavou Pink Casa Grande Yellow Casa Grande. . Little's 5-16 7-20 8-4 5-28 5-28 5-20 6-5 6-10 7-20 5-10 ^6 5-22 5-21 5-13 5-13 5-13 &-2 5-26 5-21 5-21 5-13 5-13 5-22 5-13 5-26 5-13 5-13 6-5 6-5 6-5 ^5 5-12 5-13 5-12 5-14 5-12 5-12 5-12 5-14 5-14 5-14 5-14 5-12 5-13 5-14 5-14 6-5 ^5 5-12 % 50 85 80 50 70 85 25 90 60 60 50 20 70 10 20 10 20 75 75 90 90 90 90 90 80 90 90 40 30 30 90 80 50 90 70 90 95 90 90 90 35 Date harvested 10-8 10-10 9-6 10-7 10-8 9-18 9-18 10-4 8-12 8-12 8-12 8-12 10-20 10-9 10-9 10-18 8-12 Size of plot 10-9 10-9 10-5 10-5 10-5 10-5 9-27 9-12 10-1 10-2 10-1 10-1 10-1 10-2 9-17 9-17 10-2 9-30 9-30 9-17 10-2 10-5 10-5 9-21 Acres Va Vs Va Va Va /s Va 1/5 1/40 V% % v% Vs Vs Va Vs Vs 1/16 1/40 1/40 1/80 Va Va 1/16 1/16 1/40 1/40 1/16 1/16 Va 1/5 1/16 Va Va Va 1/16 1/16 1/20 Yield per acre per plot Yield Pounds 213 12 177 194 100 18 70 21 19 261/ 23 23 10 /8 6 Va IVa 25 14 3 3 10 3 41 46 9 37 \v 4 55 25 36 24 27 60 4 14 10 8 Pounds 852 96 708 776 400 144 280 105 760 212 184 184 80 1 48 1 10 200 112 48 120 400 240 164 184 144 592 80 60 64 880 im 180 384 108 240 16 224 160 160 2^ 1 — Immature. 2 — Destroyed by prairie dogs. -Destioyed by rabbits. 3 — Destroyed by fungus disease. 574 BuLI^EiTlN 84 TABivE XLiii. — Continued Variety 1915 Tepary Little's Yellow Hopi White Hopi Casa Grande Hanson Valentine Pink Bates' Colorado Pinto.... Heward Pinto Red Hopi Lady Washington . . Bavou Date stand planted % 5-18 85 5-18 65 5-18 85 5-18 80 5-18 80 5-18 95 5-18 70 5-19 95 5-19 90 5-19 90 5-19 75 5-19 85 5-10 80 5-19 85 Date harvested 10-4 10-4 10-4 10-4 10-4 10-4 9-21 11-2 10^ 10-4 10-4 10-4 11-2 11-2 Size of plot Acres 'A Vs Vs Vs Vs Vs 1/10 1/10 'A A 1/10 Vs 1/12 Yield per plot Pounds 180 31 53 42 27 64 7 4 194 203 17 24 62 131 Yield per acre Founds 720 248 424 336 216 512 70 40 776 812 170 192 744 524 of the United States. The plot of Minnesota Grimm made the best growth, attaining a height of twelve inches during the summer. The remainder of the plots grew about one-half as tall. A growth of six or eight inches was made in both 1914 and 1915, and in 1916 all the alfalfa was plowed under. BEANS Beans are of special importance to Arizona dry-farmers. As legumes they have great value in crop rotations, and, since there are a number of varieties which have been thoroughly acclimatized throughout a long period of time by the native Indians, no surer crop can be grown on Arizona dry-farms. Six varieties were planted on the Prescott Dry-farm in 1912. See Table XLIII. Best results were obtained from Bates' and tepary beans. In 1913 six other varieties were added, the plot of teparies being destroyed by rabbits, and the Bates' variety maintaining its satisfactory yield of the year before. The highest yielding variety of beans in 1914 was Lady Wash- ington, with teparies producing satisfactorily. In 1915 the leading varieties were Colorado Pinto, Bates', Lady Washington, and tepary . Table XLIV summarizes the average yields of all plots of each variety for the four years of the test, the desirability and consistent ExpijRi MENTAL Work in Dry-Farming 575 TABLE XLIV. SUMMARY, VARIETY TEST OE REANS, PRESCOTT DRY-FARM Variety Yield per acre 19K Tepary Bates' Lady Washington . . . Pink Bayou Lima Colorado Pinto Little's Burpee's Stringless. . . Black Wax Indian Yellow Aztec Red Hopi Hanson White Hopi Yellow Hopi Casa Grande Hopi Lima Valentine Howard Pinto Spotted Stringless. . . . Yellow Casa Grande. Pounds 237 742 275 105 1913 Pounds 1 486 184 200 112 184 80 4 1 48 1914 P oil nils 368 282 490 120 240 i74 28 64 80 48 108 120 400 160 240 60 160 1915 Average Pounds 720 776 744 40 524 812 248 192 512 336 424 216 70 170 Pounds . 331 571 423 116 292 390 119 34 40 48 120 310 228 412 188 240 70 170 60 160 l_Destroyed by rabbits. 2— Immature. 3— Destroyed by prairie dogs. 4— De- stroyed by fungus disease. performance of Bates', Lady Washington, and tepary beans being shown. To determine the most favorable date to plant beans, several TABLE XLV. BEANS ; TIME OF PLANTING TEST, PRESCOTT DRY-FARM Variety Date planted 1913 Lady Washington Tepary 1914 Lady Washington 1915 ■ Lady Washington 5-10 6-10 6-20 5-16 6-20 8-4 4-10 5-4 5-10 6-10 5-19 5-10 6-10 stand % 80 70 90 85 60 70 60 85 80 50 Date harvested 9-18 10-18 9-18 10-8 10-10 9-26 9-26 9-26 11-2 11-2 11-2 Size of plot Acres Va Va /8 1/12 1/12 1/12 Va 1/12 1/40 Yield per plot Pounds 70 100 18 213 24 12 13 17 131 62 6 Yiekl per aero Pounds 280 400 144 852 192 144 156 204 524 744 240 1— Did not mature, 2— Froze down. 576 Bulletin 84 plots were seeded on various dates in 1913, 1914, and 1915. Lady Washington beans were used throughout the test, and teparies were added in 1913. The data are somewhat incomplete, though the results, supplemented by additional experience, indicate the desira- bility of May planting. See Table XLV. Of special interest is the tepary bean, which has been bred up from parent stock secured from the Papago Indians, therefore well adapted to climatic conditions of Arizona. No variety that has been tried on any of the Experiment Station farms seems so v/ell adapted. Tepary beans now on the market are white, though the parent stock included many colors. Interest is developing throughout the entire United States, and the demand is constantly increasing. When properly cooked, tepary beans have a delightful flavor, being preferred by many to other varieties. The cooking methods which are ordinarily used for other varieties of beans must be somewhat modified to obtain best results from tepar'es. They mature quickly, and, under favorable conditions, yield a very large tonnage for green manuring purposes or for hay. Teparies must be protected from rabbits. Another very promising variety of beans is Bates'. It is equal Fig. 28. — Papago Sweet corn, Prescott Dry-farm. Expkrime;ntaIv Work in Dry-Farming 577 table; XLVI. VARIKTY TEST OF NATIVE) INDIAN CORN, pre;scott dry-farm Date Daty Size Yield per plot Yield per acre Variety planted stand har- vested rtf plot Grain stover Grain Stover % Acres Pounds Pounds Pounds Pounds 1912 Yellow Hopi. . . . 5-10 9-6 Va 221 221 834 884 (( it 5-20 10-7 Va 165 232 660 928 a u 6-3 10-12 % ■ 200 381 1600 3048 it it 6-3 10-12 % 169 341 1352 2728 Pima 5-16 9-26 10-5 ■Mo 200 87 693 243 800 1740 2772 Papago Swee t.. 5-15 4860 1913 Yellow Hopi. . . . 5-26 10-13 % 92 138 736 1104 Hopi White F] int 5-15 60 10-15 V% 172 389 1376 3112 Blue Hopi. . . . . . 5-14 60 10-15 H 200 300 1600 2400 White Hopi. 5-14 60 10-15 % 26 49 208 392 Pima 5-15 10-15 10-15 1/20 271 41 544 83 1084 820 2176 Papago Swee t.. 5-14 1660 1914 Papago Swee t.. 5-12 95 9-25 1/12 41 361 492 4332 White Hopi. . . . 5-14 85 9-9 1/12 62 95 744 1140 ii ii 5-13 80 9-10 1/80 9 36 720 2880 Yellow Hopi ... 5-14 85 9-9 1/12 25 94 300 1128 t( a 5-13 80 9-16 1/80 8 14 640 1120 Pink 5-14 75 9-14 1/40 9 30 360 1200 Red . . . 5-13 80 9-10 1/40 21 26 840 1040 a n 5-13 85 9-16 1-80 13 48 1040 3840 Pinto 5-13 80 70 9-16 9-10 1/40 1/40 14 20 40 35 560 800 1600 Delicious He )pi 5-13 1400 Blue Hopi.. 5-13 90 10-3 1/40 15 75 600 3000 (t it . . . 5-13 95 10-3 1/6 48 599 288 3594 Hopi Squaw 5-13 70 9-10 1/40 14 23 560 920 Mixed Hopi 5-13 80 9-10 1/40 26 38 1040 1520 Palakai .... . . . 5-13 90 9-16 1/20 25 130 500 2600 Koescha Kai 5-13 90 9-16 1/80 20 23 1600 1840 Heroosquapa 5-13 90 9-16 1/40 15 iZ 600 1320 Pima 5-13 90 90 100 90 9-16 9-25 10-1 10-3 1/40 Va 1/40 55 "84 31 71 465 621 128 2200 "336 1240 2840 7-10 3720 a 5-13 2484 Mohave .... 5-13 5120 White Flint. 5-13 90 10-3 1/40 25 71 1000 2840 1915 Papago Swee t.. 5-18 100 10-10 /s 21 500 168 '4000 « « . . . 5-19 95 10-21 ^ • • • • > t «... .... Yellow Hopi . . . 5-18 95 10-10 Ks 98 15 784 1256 Red . . 5-18 95 10-10 ^ 44 165 352 1320 Mixed 5-18 95 10-10 1/20 37 101 740 2020 Blue . . 5-17 95 10-6 V% 99 134 792 1072 White 5-18 95 10-9 Vz 143 200 1144 1600 Hopi Squaw. 5-18 95 10-10 /8 103 98 824 784 Pima 5-18 40 95 95 10-11 10-9 10-10 1/40 'A 1/12 19 154 126 80 249 596 760 1232 1512 3200 it 5-18 1992 White Flint.' • 5-18 7152 578 Bulletin 84 i.i quality to any kidney beans, and is particularly adapted to the climate of many regions in Northern Arizona.* In 1914, a fungus disease appeared, the greatest damage being done to pink beans. CORN Native Indian Varieties: For convenience in comparison, tables recording variety tests of corn are divided into two groups, native Indian, and improved American varieties. The origin of In- dian varieties is not known further than that they have been grown for a great many years by various tribes in the State. Some have distinct varietal characteristics, while others should be considered merely as races. In Tables XLVI and XLVII Papago sweet is included among Indian varieties, though it has been bred up and adapted until it may well be considered an improved American variety. Three varieties of native corn. Yellow Hopi, Pima and Papago sweet, were planted in 1912. The best yield, 1740 pounds of ear corn per acre, was obtained from the plot of Papago sweet. Two plots of Yellow Hopi yielded 1352 and 1600 pounds of ear corn per acre, respectively. See Table XLVI. Supplementing varieties grown in 1912, Hopi White Flint, Blue Hopi, and White Hopi were added to the test in 1913. The best yield was obtained from Blue Hopi. In 1914, Mohave, several additional strains of Hopi, and three varieties, Palakai, Koescha Kai and Heroosquapa, obtained from Toriva, were added. The maximum yield of 2200 pounds of ear corn per acre was secured from a plot of Pima. Fewer varieties were planted in 1915, the best yield being ob- tained from a plot of White Flint. In Table XLVII, which summarizes the variety test of native Indian corn, annual yields represent the average of all plots of the specified variety for the given year. The desirability of certain Indian varieties of corn for dry- farming is clearly evident. A degree of drought resistance has been bred up by natural selection for an unknown period of years, ♦For a description of bean varieties see Arizona Agricultural Experiment Sta- tion Bulletin No. 68, "Southwestern Beans and Teparies," by George F. Freeman. EXPEIRIMENTAL WORK IN DrY-FaRMING <: n ^. o o o ^ en p tQ t:.P p P 3^ '*' ft) . , OP*" ""Op p O M to 4:^0 ON- O O to CO tsJ s COOONJi-On. Oj • • • • tsj 1— ' t\J I— ' o I—- • • Oj 4^ 1— H- ON s — • . • • O OO vjCns t^ • • ■ • l\j0 4i.ONOo, t\J 0\ On tJi O t-n Cn ■ -t' OO O OOnOn- OOOOOOO- ^3 OOOJNOO^I-P^*.00-t>.5: ^ ^ r. ,^ , , ,.^ ^j 4i. vo = .. O OitsJ B. OON4i.4^0j4i^J4>.NO: O O O O to ^ <~ ■ ■ ■ • Ln ^ 1— K> rsj >-' 1— CO OJ On 00 ON VO • K) 4^ IsJ O 4^ O lO • OOOOOOO- >-'^^hO>-'t\)OJ>-'Oj4^o 4^b04^tJ>0 1vJ^OOjj; O O 4^ to — \0 to ■— Oj 3 OOOOOVI4i.tjit\Jn. Or 00 • ^. to- to- 4^- Oj vj 1-- ^vj ^j \0 s (jn4^+k\O00O00a tN)0+>.t04^0N4ici. cn - to- 00- 4^- H^tO^v-'^tOtO^ OoOONOtOCnOS lO to O VI Ln NO C i OOOtoONONCS rOCTiO>tntOtnO\OJOOtoC3NOOO>OviiOVi~ ^OOOaiCTl>£>VIOCri4^tO«D4^-viOoOOa OOOOa\OtOONOOCTiOCntnOO^-«»n. tnhJi-'tO-^"-' oJi-'>-'^-''-''-'to>->toOo!p ^-«00WO^^OO^00^4^tO00VIOJ^J^O^^05 tO^tOOvOOcni-'OOOOViootnvi^^i-'t: OOOOa^OtOtOOOOO-^CTlOOW5^ < d > > PI k; ►^ o > < I— I o I— ( > ;^ n o w . jz; w n o o k; I > 579 580 Bulletin 84 TAHLE XLVIII. VARIETY TEST OE IMPROVED AMERICAN CORN, PRESCOTT DRY-FARM Date Date Size Yield per plot Yield per acre Variety planted tif a nr? >1 Q r>_ r^f O tdliU vested plot Grain stover Grain stover 1912 % Acres Pounds Pounds Pounds Pounds' White Dent 5-16 9-19 Va 213 857 852 3428 a a 5-28 80 10-12 Va 400 1019 1600 4076 Reid's Yellow Dent 5-24 10-12 Vs 100 315 800 2520 Reid's Yellow Dent 5-22 10-7 'A 412 865 1648 3460 Rice Pop 5-20 ... 10-7 1/20 IS 125 300 2500 Mexican Black 5-22 10-12 'A 19 349 76 1396 Sweet 5-20 10-7 1/20 27 375 540 7500 1913 Brown County Yellow Dent ^10 60 10-13 Vs 121 204 968 1632 Brown County Yellow Dent 6-10 60 10-8 Vs 51 51 408 408 Strawberry .... 6-10 60 10-13 Vs 218 327 1744 2616 it 6-10 60 10-8 Vs 178 267 1424 2136 Mexican Black 5-23 60 10-14 A 83 166 332 664 Bloody Butcher 5-15 60 10-15 A 416 789 1664 3156 ti it 5-15 60 10-15 1/10 210 285 2100 2850 Sixty Day 5-15 60 10-15 A 78 234 312 936 King Philip.... 5-15 60 10-15 I/IO 234 540 2340 5400 White Dent 5-15 60 10-15 Vs 200 335 1600 2680 a li 5-15 60 10-15 I/IO 121 484 1210 4840 Red " ." ; ; 5-14 60 10-15 Vs 125 260 1000 2080 Maul's Yellow Dent 5-14 60 10-15 Vs 46 93 368 744 Elgin Yellow Dent 5-14 60 10-15 Vs 41 83 328 664 Reid's Yellow Dent ........ 5-21 10-18 Vs 490 739 3920 5912 Hickory King.. 5-21 , , 10-13 A 363 1180 1452 4720 Sweet 5-23 • • 10-14 I/IO 317 317 3170 3170 1914 Colorado Yellow Dent 5-12 95 9-27 A 225 656 900 2624 Colorado White Flint 5-12 80 9-16 Vs 35 221 280 1768 King Philip 5-13 95 9-27 1/12 25 208 300 2496 Swadley 5-13 95 &-5 A 275 336 1100 1344 White Dent 5-13 95 10-1 % 18 1144 72 4576 hk a 5-14 90 10-12 1/6 605 1266 3630 7596 ti a 6-5 60 9-19 A • • • 772 • • > • 3088 Reid's Yellow' ' Dent 5-13 90 9-27 A 110 1463 440 5852 Reid's Yellow Dent 5-14 10-12 3/20 199 628' 1326 4187 Maul's Yellow Dent 5-13 95 9-28 As 206 414 1648 3312 Maul's Yellow Dent 5-14 90 9-15 1/12 67 360 804 4320 1 — Calculated from green weight. 2 — Failed to come up. ExpERiMENTAiv Work in Dry-Farming 581 TAP.LK XLVIII— -Continiied Date Date Size Yield per plot Yield per acre Variety planted stand har- 01 -~ vested plot Grain stover Grain stover 191^— Continued % Acres Pounds Pounds Pounds Pounds Red Dent 5-14 90 9-14 1/20 13 225 260 4500 Brown County ^'cllnw Dent. . 5-14 95 9-15 1/12 76 170 912 2040 Strawberry .... 5-12 40 9-28 Va 88 277 352 1108 White Australian 5-12 85 8-5 Va 225 448 900 1792 Stooling Bra- zilian Flour.. 5-12 100 9-21 Va 25 1224 100 4896 Bloody Butcher 5-13 80 10-1 % 164 1661 656 6644 Mexican Black 5-13 40 10-1 Va 20 190 80 760 June 5-13 95 9-15 1/40 . . . 631' .... 2527 Iowa Silver Mine 7-10 9-25 % • ■ > 170' .... 1363 White Pearl... 7-10 9-25 % • • • 107' 857 Learning 7-10 9-25 v% 168' .... 1341 White Wonder 7-10 9-25 Va . > . 253' .... 1011 Gabarino 5-27 70 10-6 1/10 78 252 780 2520 Sixty Day 5-13 95 9-15 1/40 10 18 400 720 Rice Pop 5-14 95 9-15 1/40 10 105 400 4200 Sweet 5-13 ^22 100 75 10-1 9-19 Va Va 155 840 722 620 3360 Eureka 3088 Chub 5-13 80 9-28 1/20 '23 255 "460 5100 1915 Red Dent 5-18 95 10-10 v% 187 273 1496 2184 White " 5-18 70 10-11 1/40 27 100 1080 4000 Brown County Yellow Dent. . 5-18 50 10-11 1/20 44 111 880 2220 Reid's Yellow Dent 5-17 95 10-6 Ks 220 301 1760 2408 Maul's Yellow Dent 5-17 95 10-9 Ks 200 497 ,1600 3976 King Philip. . . . 5-18 95 10-10 /8 200 317 1600 2536 Chub 5-18 95 10-10 1/16 41 155 656 2480 Strawberry 5-18 2 .... (( 5-19 70 16^21 "% . . . .... . . . f Iowa Silver Mine 5-18 95 10-10 1/20 71 409 1420 8180 Elgin Rice Pop 5-18 95 10-10 /8 81 161 648 1288 5-18 95 10-11 1/20 11 69 220 1380 Bloody Butcher 5-17 95 10-6 V?. 215 290 1720 2320 If O o w W D t/j i-r < ■4-) CO en 0) O !- a; > o CO c u 0 > O 0 > o -t-> Pi Buivi^ETiN 84 ■oc^^O'-^u20T^r^^^^^foo^oo^ooooooc^^ovDoo^~■^^^^l-HOOO KOO>ONS^^tMO^>•^OO^t^^Otr-~(MO*O^O^O^T^C^J^~.u^<;^,-^C^)00 SO'-lCTlC0^^^D^O^^-lVD00O^Ol00v0f~CTl^r^(MO"^^^00C0OlOO s0^co.-l^Ot^JO^0»-^T^OCTlU^00l^)^^0000u^u^u^ ._( . . .no aO^NCTiOoOCTi'-H'a-vorO'-H'-c^roOCJvOuiOOfO •t'^ • • •!>. ^ O Q 00 t^ Ol • \0 <^ S-^ O --I On rg • ^ - S tVl -^ CN) <^ CM ' 11, •OM3O00 ■CC OnO CO ■ o •CO .— I U-) ■ CO Tj- ^O CM • Tf •ooo o -o • 00 oc' o o -00 ■ Ti- n- CO (M • ^ C^J CO • 00 t,C o \o oo -a-O OO ON O 00 s r^ C Tt- \o 00 • oo ■ VOO •00 NO • o ooooo • rvioo 00 rj- • CM rvi rsivo ■NO ■ On •NO ■— ' t^ CD lO CO CO CO O lO o . ,— , ^^ u^ ^H Tt- CM ^H _ ,- (M ro ^jco^ONoc^iovoorviooo -o ^cocoNO'^^^HOloou^ocC'C^^ o - 00 CM CM CM On CJN NO ro ro Tf no • rj- ■ooooo O •OOONOOO 00 ^ ^1 O O Tf O S ^ NO00T}- CM •-* O-* NOO ■ n£) f^ NO ro CM ■ NO —'NO ON t^ CO -.J- •a Ou^O 00 00 K fM O O NO NO sOn-'S-Oco NO o CO — I .— I ■ P^l O ■* • CM O 00 CM C^l ■CJOTfOO -cot^C^l^-ir) ■OQcom . CO -— ' CO CO -rt- • t— I CM '— < • CO >— * SOCM ONOO 3 ON u^ O ON O C)3Nr^ locoi-o O^CMco rvj^i^ 'u > 1;*^ ONOO ~ "M C^J r^ lO c o Q o 1) - :H-?-a c o Q O '^ >>^ -4-' 1— < §^ ^•§ C rt 1^ 1- o I- w u O be O C >. 1- o. - > -^^.^-7^ .= iP..^ O rt"-i-" O X 03 I- ^_ -^ l- 3 u u < be n n: to bc!^ (U ■" O dJ ■" (U "^^ rt-c-S !:; C=i;^to;5cQUtoU^c/2(ii!Sty}tolGO^Uc/2U^c/il§h2^ j^Gtol Expf,rime;ntal Work in Dry-Farming 583 and no surer varieties will be found than those obtained from the Indians. Improved American Varieties: Five varieties including sweet, dent and pop corn were planted in 1912. See Table XLVIII. The heaviest yield was obtained from a plot of Reid's Yellow Dent, a plot of White Dent yielding the next largest amount. The 1913 corn test included'thirteen varieties, the highest yield being secured from a plot of Reid's Yellow Dent, the next best yield coming from a plot of King Philip. Twenty-five varieties were tested in 1914, the best yield, 3630 pounds of ear corn per acre, coming from a plot of White Dent. Of the eighteen varieties tested in 1915, the best yield, 1760 pounds of ear corn per acre, was obtained from a plot of Reid's Yellow Dent, a plot of Bloody Butcher coming second, with a \ield of 1720 pounds per acre. In summarizing the test of improved varieties of American corn, yields for a given variety in any one year are calculated by averaging all of the plots of that variety grown in the year speci- fied. As will be seen in Table XLIX, best results were obtained from Reid's Yellow Dent, while King Philip, Bloody Butcher, Hickory King, and Maul's Yellow Dent were promising. Table XLIX shows an especially heavy yield of earn corn for the season of 1913. The distribution of summer rainfall at this time apparently supports the theory that an excess of moisture dur- ing the earlier growing period tends to exaggerate vegetative growth at the expense of grain production. In 1913 the summer rainfall was somewhat delayed- not beginning until after the corn plants had begun to form grain, and, as a result, grain formation was stimulated at the expense of vegetative growth. FRUIT To determine the practicability of fruit raising by dry-farming, 2. small orchard of the following varieties of trees was planted in the spring of 1912: Apples: King David Rome Beauty White Winter Pearmain Arkansas Black Gravenstein 584 Buli.e;tin 84 Pears: Sickle Bartlett Winter Bartlett Dannas Clap Favorite Cherries: Napoleon English Morrelo Bing Plums: Grand Duke Burbank Washington Peaches: Salway Prunes: Hungarian One tree of each of the above varieties was planted, excepting King David apples, of which three trees were set out. During the winter of 1912 and 1913 some of the trees were girdled by rabbits and were replaced in the spring of 1913 with new stock of the same varieties. In the spring of 1913 a few grape vines were planted, including piincipally Concords, with one Mission and one Niagara vine. Two English walnut trees were planted early in 1913. On June 26, 1913, each tree received fifteen gallons of water, and each grape vine ten gallons, the only irrigation supplied since planting. A little fruit was produced by the plums and the grapes in 1915. and all of the trees have made a healthy growth. Fruit production in 1916 and 1917 increased normally. The moisture content of the orchard plot (see Table L) indi- cates that, with careful and consistent cultivation, a slight amount of moisture may be stored in the soil, especially in the area below the second foot. In 1911, about thirty days after the land was broken, the soil was so dry and hard below the fifth foot that sam- ples could not be obtained with the soil auger. The condition was improved in 1912, and a sample was secured from the sixth foot, while in 1913, 1914 and 1915, samples to a depth of eight feet were readily obtained. It appears likely that sufficient moisture can be stored in the soil to make production of dry-farmed fruits for home Expe;rimkntal Work in Dry-Farming 58.3 use practicable, and, after the trees have come into full bearing, one or two irrigations per annum may suffice to make orcharding profitable. Table h. moisture; determinations, prEscott dry-e.vrm orchard Date of taking sample 1st ft. 2nd ft. 3rd ft. 4th ft. 5th ft. 6th ft. 7th ft Sth ft. Yearly- Aver- age 9- 3-11 9- 7-12 5-13-12 9-20-14 5-28-15 Avge. Average 14.28 14.3 17.8 8.4 16.4 14.24 for p 15.21 17.6 20.10 14.40 20.00 17.46 ■^riod 9.68 19.30 16.70 12.00 20.20 15.58 13.36 14.10 16.50 11.20 17.00 14.43 9.23 9.50 15.30 15.20 17.40 13.33 '8.30 13.70 13.20 18.50 13.43 is^oo 15.90 21.80 16.90 14.90 22.90 18.90 12.35 13.85 16.00 12.90 19.28 14,80 ..15.53 potatoes The climate of northern Arizona at an altitude of 5000 feet or more is somewhat favorable to potato growing, and, with suitable soil and ample moisture, large yields can be secured. Market prices Fig. 29. — Potatoes damaged by potato stem borer, Prescott Dry-farm. 586 BuIvLStin 84 TABLE LI. VARIETY TEST OE POTATOES, PRESCOTT DRY-EARM Date Date Size of Yield Yield "Variety planted Stand harvested plot per plot per acre % Acres P0!t".ds Pour J s 1912 White Star 5-21 90 12-28 1/20 95 1900 (( a 5-24 90 12-28 Vb 210 1680 Blue Victor 5-21 90 12-28 1/15 460 6900 Early Rose 5-21 90 12-28 1/15 231 3465 1913 Wynekoop 5^ 70 11-8 H 390 1560 (( 5-21 85 10-18 Vs 149 1192 (1 5-21 85 10-18 1/20 151' 3020 Blue Victor 6-2 20 11-8 1/40 2' 80 White Star 6-2 5 1/20 2 .... Irish Cobbler 5-2 60 ii^' 1/20 "S' 100 a i( 5-2 70 10-20 . Vs 79" 632 Early Rose 6-2 75 11-8 1/40 15" 600 Red Ohio 5-2 70 10-20 1/20 19" 380 1914 Irish Cobbler 4-21 75 11-28 'A 101 404 (( « 4-24 70 11-21 1/10 38 380 7^' 11-7 9-4 &-1 9-9 9-28 6-2 6-25 6-11 6-25 6-29 6-28 6^ii 6-11 6-27 6-27 6-27 Size of plot Acres Vs 1/7 "% Va Vz Vs Vs 1/20 1/20 1/20 /8 i/24 1/12 9-28 % Va Va % Va Va 1/20 Va V 1/48 3/40 3/40 3/40 Yield per plot Yield per acre Grain Founds 40 36 '35 12 Va 12 2/2 30 5 24 10 19 15 12 '56 21 straw Pounds 75 34 225 110 85 e 6 T 40 Grain 300 35 191 27 131 113 88 302 73 12 I 88 i 20 i 93 16 , 86 straw Pounds Pounds 320 ' 600 252 : 23S 140 48 48 '60 200 168 160 266 213 900 40 880 680 160 "72 8 i 28 120 1200 20 140 96 764 80 216 76 524 60 452 240 ' 1760 1 208 584 1173 1240 1146 1 — Winter killed. 2 — Died of drouth. 3— Disced Aug. 15. 4 — Destroyed by rab- bits. 5— Disced Sept. 15. 6— Pastured. 7— Disced Aug. 9. 590 Bulletin 84 TABLE Liii — Continued Variety 1914 — Continued Crimean C. I. 1 436 Crimean C. I. 1435 GhirkaC. 1. 1438 Bula:arian C. I. 2048 Bluestem Kubanka 1915 Kharkov C. I. 1442 Kharkov C. I. 1355 Arinaviar Ghirka C. I. 1438 Bultjarian C. I. 2048 Reel Fife Marquis Date planted White Aus- tralian Early Baart. . . Gold Coin Crimean C. I. 1435 Crimean C. I. 1437 Crimean C. I. 1559 Kubanka Bluestem Koffoid Minnesota Fife No. 43 Turkey Red. . . 8-25 9-25 8-25 8-25 10-^ 8-25 10-12 10-12 10-12 10-12 10-12 10-10 9-30 10-10 stand 10-10 60 10-10 70 10-10 65 10-12 10-12 10-12 10-12 10-12 9-30 9-30 10-10 % 85 85 85 85 95 85 90 90 90 90 85 90 95 95 85 80 80 75 95 95 95 95 r>ate har- vested ^25 6-25 6-27 6-26 6-26 6-28 7-21 7-21 7-21 7-21 7-21 7-20 7-10 7-20 7-19 7-20 7-19 7-20 7-20 7-10 7-10 7-6 Size of plot Yield per plot Yield per acre A cres 3/40 3/40 1/40 3/40 1/48 1/10 1/40 1/80 1/40 1/20 1/20 1/10 % 1/6 1/42 1/11 2/11 1/20 1/40 1/12 1/7 I/, Grain Straw Pounds 15 14 7 23 2 14 5 7 14 15 34 160 71 17 10 25 41 34 104 100 112 Pounds 135 90 100 146 ■96 84 18 13 17 27 31 78 455 121 28 17 Grain Pounds 200 173 280 306 96 140 320 400 280 280 300 340 1280 426 340 400 49 300 81 287 72, 272 312 832 401 800 416 896 Straw Pounds 1800 1200 4000 1946 960 840 720 1040 680 540 620 780 3640 726 560 680 588 567 584 2496 3208 3328 8— Destroyed by prairie doRS in April. added. The largest yield was 1560 pounds per acre from a plot of Russet Burbank potatoes. In both 1914 and 1915 considerable damage was done by Colorado potato beetles. SMALL GRAINS Wheat: In the fall of 1911 several plots of wheat were planted on virgin land which had been broken in August and September, Experimental Work in Dry-Farming 591 but were entirely destroyed by prairie dogs and rabbits during the winter. Four varieties were planted in the fall of 1912 and fourteen varieties in the spring of 1913. See Table LUL Hard red winter, semi-hard spring, and soft bread wheats, macaroni wheats, and one plot of PoHsh wheat were included in the varieties. The best yield was obtained from a plot of Turkey Red planted September 10. Thirteen varieties were planted in the fall of 1913, including the same classes of wheat as were used the previous year, with the addition of Poulard, a variety known by several names, such as Miracle, Alaska, and Seven-headed. The best yield was from a small plot of Bulgarian C. I. No. 2048. Better returns were secured in 1915, a plot of Marquis yielding 1280 pounds of grain per acre. A summary of the variety test of wheat on the Prescott Dry- farm is given in Table LIV. In this table annual yields of a given variety represent the average of all plots of that variety in the year named. To determine the most favorable date to plant wheat, a number TABLE LIV. SUMMARY, VARIETY TEST OE WINTER WHEATS, PRESCOTT DRY-EARM Yield per acre Variety 1913 1914 1915 Average Grain straw Grain Straw Grain | Straw Grain Straw Pounds Pounds Pounds Pounds Pounds Pounds Pounds Pounds Turkey Red 152 435 110 743 896 3328 386 1502 Early Baart Bluestem '96 960 272 584 123 515 Kubanka 140 840 287 567 142 469 Sonora 20 140 20 140 Club Head • > • .... Marquis Polish 200 1208 853 2i83 526 1695 168 160 584 1173 360 880 168 260 584 TCharkov 1026 Arinaviar 266 1240 280 680 273 960 C!rimean 195 1382 347 609 271 995 Ghirka .... 280 4000 280 540 280 2270 Bulgarian Red Fife 306 1946 300 340 620 780 303 340 1283 780 White Australian • • • .... Gold Coin Koffoid . . . 832 2496 832 2496 Minnesota Fife No. 43 880 3208 880 3208 592 BUI.I.ETIN 84 TABLE LlVa. SUMMARY, VARIETY TEST OF SPRING WHEATS, PRESCOTT DRY-EARM Variety Yield per acre 1913 Grain straw Turkey Red Pounds "6 '48 '30 4 m Pounds Earlv Baart 195 Bluestem 40 Sprinsr Turkey Gold Coin McOmie Polish 160 Red Russian Hopi 36 Red Fife 140 Club Head Koffoid New Zealand izoo White Australian of plots of different varieties were seeded at various times in 1913, 1914, and 1915. Table LV records the results and indicates the de- sirability of planting- in August or early in September. Table LIII indicates a heavy production of straw, compared \\ith the yield of grain in 1914. This was probably due to the wet sprang of 1914 and to thick seeding, the stimulated vegetative growth utilizing available moisture from the soil to such an extent that, upon fruiting, there was insufficient moisture satisfactorily to mature the grain, which was light and shrivelled. While the grain produced in 1914 was insufficient to insure reasonable profits, the possibilities of w^heat as a hay crop are indicated. The production of winter wheat on dry farms in the Great Plains and in the Northwest is usually considered the most profit- able branch of the business. Persistent trials with some of the hardiest varieties, however, have failed to indicate that wheat can be profitably grown in the Prescott vicinity without irrigation. Serious winter killing occurs even though the minimum tempera- tures of winter are seldom very low. Plots planted in early fall occasionally return profitable yields when the snowfall in winter is sufficient and constant enough to prevent winter killing. Wheat should be seeded thinly on dry farms, thirty-five pounds per acre being sufficient. Oats: In the fall of 1912 two varieties of oats, Texas Red, and Experimental Work in Dry-Farming 593 TABLE LV. WHEAT, TIME OE PLANTING TEST, PRESCOTT dry-earm Date Date Size Yield per plot Yield per acre Variety planted Stand har- vested of plot Grain straw G-rain straw % Acres Poutids Pounds Pounds Pounds 1913 Turkey Red... 8-10 90 7-3 Va 180 195 720 780 tt ti 9-10 90 6-30 % 40 75 320 600 « « 10-5 80 7-22 1/7 36 34 252 238 « (( 10-5 1 * i< « 10-10 1 « « 10-10 80 7-23 "% '35 "140 « (( 11-10 50 7-23 Va 12 '22 48 "88 Kubanka 10-5 1 Bluestem 10-5 1 1914 Turkey Red... 8-10 85 6-25 % 18 100 72 400 t( a 9-10 90 6-25 Va 24 191 96 764 >( • * 2 t • > • 1915 Turkey Red... 8-10 95 7-6 % 73 220 584 1760 « (1 9-10 95 7-6 % 96 254 768 2032 H (t 10-10 95 7-6 % 112 416 896 332S tl l( 11-10 95 7-11 % 51 185 408 1480 Crimean 10-12 85 7-19 1/20 17 28 340 560 Kubanka 10-12 75 7-19 1/7 41 31 287 217 Bluestem 10-12 95 7-20 Vs 34 73 272 584 Koffoid 9-30 95 7-10 % 104 312 832 2496 Club Head.... 9-30 , , 7-10 % . Marquis 9-30 95 7-10 Vs 160 455 1280 3640 Minnesota Fife 9-30 95 7-10 Vs 100 401 800 3208 1 — Winter killed. 2 — Plowed under Aug. 23. Red oats from Snowflake, were planted, both of which were winter killed. Two varieties, Sixty Day and Red (Snowflake), planted in the spring of 1912, were destroyed by prairie dogs. Six varieties were planted in 1913, the highest yield being only 160 pounds of grain per acre. In 1914 two plots of black oats, an unidentified variety grown near Eagar for a number of years, were tested, but \ielded only eight pounds of grain per acre. Three varieties were planted in 1915, all being killed by drought. The production of oats without irrigation in the vicinity of Prescott is very question- able. See Table LVI. 594 Bulletin 84 T.NP.LE LVL VARIETY TEST OF OATS, PRESCOTT DRY-EARM Variety Date planted Date har- vested Size Ol plot Y'ield per plot Yield per acre Grain straw Grain straw 1912 Texas Red Red (Snow Hake) .... Sixty Day 9-10 10-7 4-5 4-5 4-11 7-10 4-16 7-15 4-11 4-16 7-9 4-11 7- in 4-16 4-11 4-20 4-15 4-15 4-15 6-io 6-10 11^ 11-7 \\-7 \\-7' 11-4 tl-4 9-28 9-28 Acres "%' 1/16 1/24 % Va Va 1/20 1/20 1/20 Pounds Va • ' ' 10 3 SVa 2 2 Pounds 1 1 2 2 5 47 3 3 '87 11 35 4 11 7 s s E Pounds 6 i60 72 26 8 8 Pounds Red (Snowflake) .... 1913 Black 40 376 Texas Red it a New Alberta Sixty Day 11 ii 1392 Russian Kherson 264 280 " 1914 Black 44 28 1915 Utah Sixtv Dav Texas Red New Alberta 1 — ^Winter killed. 2 — Destroyed by prairie dogs. 3 — Disced Aug. 15. 4 — Disced Sept. 18. 5 — Killed by drought in June. Barley: One plot of Six Row barley was planted May 14, 1912, and yielded forty-eight pounds of grain per acre (see Table LVII). One plot each of Six Row and White Hulless barley, planted in the fall of 1912, failed to survive the winter. In 1913, Black Hulless, Mansury, and Six Row barley were planted early in April, but all were destroyed by drought. The test in 1914 included Six Row, Black Hulless, White Hull- ess, Oderbrucker, Utah Winter, and Mansury barley, all of which failed, the greatest yield, forty pounds of grain per acre, coming from the Utah Winter plot. In 1915 Utah Winter and Black Hulless barley were planted, the former producing 200 pounds of grain per acre. There is little likelihood of barley withstanding the open win- ters of the Prescott vicinity, and, when planted in spring, it is apt to be destroyed by drought. Therefore, it is improbable that bar- ley ever will become an important dry-farm crop of the region. Rye: A plot of rye planted in November, 1911, yielded at the late of 180 pounds of grain per acre. Spring rye in 1913 yielded no Experimental Work in Dry-Farming 595 TABLE LVII. VARIETY TEST OF BARLEY, RYE, EMMER, AND SPELTZ, PRESCOTT DRY-FARM Variety Date planted 1912 White Hulless barley Six Row barley Rye 1913 Black Hulless barley Six Row barley Mansury " Spring rve. . . . 1914 Six Row barley it it a Black Hulless barley White Hulless barley Oderbrucker barley Utah Winter barley Mansury barley Rye Stand Speltz Emmer 1915 Utah Winter barlev Black Hulless barley Black Hulless barlev Black Winter emmer Rye Red Winter speltz C.I.1772 10-7 5-14 10-7 11-11 4-7 4-11 4-11 4-11 3-19 7-10 4-15 4-11 4-15 4-11 8-25 4-15 7-10 9-17 4-20 10-6 10-12 9-30 10-10 10-10 10-10 10-12 % 85 95 95 70 80 Date har- vested Size of plot 9-30 7-22 8-1 11-7 ^28 [1-7' 6-11 6-26 7-21 7-19 A cres 1/6 ^ /8 1/40 1/20 1/10 1/20 /8 Va 1/20 1/20 /8 1/9 Yield per plot Yield per acre Grain Straw Grain Pounds 12 '36 250 4 10 38 Pounds 130 ieo 10 18 60 537 18 29 71 Pounds "48 180 40 1000 80 200 342 straw Pounds "520 "96U 40 U4 600 2148 360 580 639 l_Winter killed. 2— Disced. 3— Killed 5 — Failed. 6 — Destroyed by prairie dogs. by drought. 4 — Destroyed by rabbits. grain and only forty pounds of straw per acre. One plot in 1914 failed utterly, while a second produced at the rate of 1000 pounds of grain and 2148 pounds of straw per acre. In 1915 the only plot seeded was destroyed by prairie dogs. As a hay crop rye is prob- ably the most promising of any of the small grains. It should be 596 Bulletin 84 Fig. 32. — Winter rye, Prescott Dry-farm, June 24, 1915. planted in early fall at the rate of about thirty pounds of seed per acre. Emmer: The first plots of emmer and speltz were planted in 1914, one being destroyed by rabbits, while the other, a plot of speltz planted April 20, yielded eighty pounds of grain per acre. Black Winter emmer planted in 1915 was destroyed by prairie dogs, while Red Winter speltz C. I. No. 1772 yielded 342 pounds of grain per acre. SORGHUMS While sorghums were introduced into the Southwest compara- tively recently, they are already recognized by many as the surest producers of both grain and forage in times of drought. In the following discussion, sorghums will be divided into the two usual classes according to their special adaptation ; forage sorghums and grain sorghums. Forage Sorghums: Amber and Club-top sorghums were grown in 1912, the former satisfactorily maturing, the latter failing to ripen seed. In 1913 African sorghum and Sudan grass were added to the Experimental Work in Dry-Farming 597 Fig. 33.— Club-tOD on bottom land, Prescott Dry-farm, yield lio.Uutt pounds per acre green foraee. test, the biggest yield coming from Club-top, which still failed to mature. Sumac and shallu were included in the experiment in 1914, the biggest yield again being obtained from Club-top. In 1915 Club-top and Dwarf milo were mixed for ensilage pur- poses, such a mixture furnishing a large tonnage of green fodder -containing a fairly high percentage of grain. Best results were obtained from Sumac, the Club-top and milo mixture coming second. See Table LVIII. Average yields of all plots of forage sorghums for each year are recorded in Table LIX. The desirability of Sumac, Club-top, and Amber is indicated. 598 Bulletin 84 TABLE LVin. FORAGE SORGHUMS; VARIETY TEST, PRESCOTT DRY-FARM Variety 1912 Amber Club-top 1913 Club-top African Amber Sudan grass. 1914 Sumac Club-top Shallu Sudan grass. . . 1915 Sumac Amber Sudan grass. . . Mixed Club-top and milo. . . . Date planted Date Stand har- vested 4-26 5-17 5-18 5-14 4-30 5-2 5-14 7-12 7-12 7-12 7-9 4-16 4-18 4-18 4-17 4-18 4-17 4-18 5-17 5-13 5-13 5-13 % 80 95 20 70 95 95 95 95 60 70 95 100 95 95 100 100 100 95 9-19 10-1 10-7 10-15 8-16 10-15 10-15 11-4 9-17 11-4 11-7 9-22 9-24 9-21 9-22 9-28 9-10 9-17 10-25 9-23 9-23 9-24 Size Yield per plot Yield per acre of plot Acre- Va % Va V% Va Va % 1/12 1/160 1/20 I/IO Va Va Vs Va 1/12 Va Va Va Vz Va Grain Stover Grain Stover Pounds _ Pounas Pounds _ Pounds 105 1125 420 4500 196 1715 784 6860 891 3564 435 3480 1710 • • • • 6840 357 1428 34 417 272 3336 12 230 144 2760 22 , 3520 5 120 100 2400 3 19 30 190 186 839 744 3356 675 3717" 900 4955 250 2979' 666 7941 1600 6400 61 154 732 184S 21 115 84 460 357 1227 1428 4908 6254' 8339 1734' 346S 554 2216 8453' .... 4227 1 — Calculated from green weight. TABLE LIX. SUMMARY, VARIETY TEST OF FOR.'\GE SORGHUMS, 1912 1913 1914 1915 Average Variety Grain Stover Grain Stover Grain Stover Grain Stovfr Grain Stover Pounds Pounds Pounds Pounds Pounds Pounds Pounds Pounds Pounds Pounds Amber 602 5680 272 3336 3468 291 4161 Club-top * > • 3564 5160 666 7171 • • . • 222 5298 African .... 1428 . . . 1428 Sudan grass • • • ■ < > • 69 2218 756 2684 2216 275 2373 Sumac 822 4156 8339 411 624» Shallu • • • > 732 1848 732 184S Mixed Club-top and milo ... 4227 4227 Grain Sorghums: Six varieties of grain sorghums were tested in 1912 (see Table LX ), the best yield being produced by Dwarf milo, while plots of Red and Black-hulled White Kafir yielded fairly satisfactory amounts of forage. ExrURiMKNTAL Work ix Drv-Farming 599 600 Bulletin 84 TABLE LX. GRAIN SORGHUMS; VARIETY TEST, PRESCOTT DRY-FARM Variety Date planted stand Date nop — Size Ol Yield per plot Yield per acre Jict I vested plot Grain Stover Grain stover 1912 7c A cres Pounds Pounds Pounds Pounds Dwarf milo. . . 5-10 10-16 % 229 7S7 916 3028 Standard milo 4-16 10-7 Va • • • . . . ■ t • ■ > I Red Katir 5-20 10-8 Va 1181 .... 4724 Shallii 5-20 10-12 Ya 177 829 708 3316 Black-h u 1 1 e d White Kafir 5-20 10-8 Va . . . 612 1 > > • 2418 Black-h u 1 1 e d White Kafir 5-17 10-9 Va 1029 4116 Jerusalem corn 5-16 10-9 Va '67 359 268 1436 1913 Feterita 5-2 10-17 Va 75 76 300 304 Shallu 5-14 10-15 Va 44 107 176 428 Black-h ti 1 1 e d White Kafir 5-26 10-13 Vs • > • 310 2480 Black-h u 1 1 e d White Kafir 5-26 10-16 Vs • • • 706 5648 Black-h u 1 1 e d White Kafir 4-30 20 10-16 Va 274 1096 Black-h ti 1 1 e d White Kafir 5-14 70 10-15 Vs, 270 2160 Dwarf milo. . . 5-21 10-13 Vs 312 468 2496 3744 Double Dwarf milo 5-2 40 10-15 Va 103 103 412 412 White milo. . . . 5-23 10-14 V 483 663 1932 2652 Sudan Durra. . 5-14 80 10-17 3/40 30 90 400 1200 Kowliang .... 5-23 90 10-14 1/10 50 250 500 2500 ii 5-14 85 10-15 3/40 44 87 586 1160 Red Kafir.!!'.'. 4-28 100 10-14 Va 1165 .... 4660 Pink " 5-2 100 10-15 V 844 . 6752 Jerusalem corn 4-28 85 iO-15 Va iio 411 440 1644 1914 Dwarf milo. . . 4-18 95 9-27 Va 390 671 1560 2684 Double Dwarf milo 4-1 S 95 9-27 Va 360 655 1440 2620 Standard milo 4-18 60 9-27 Va 370 600 1480 2400 White 4-17 50 9-25 Va 220 355 880 1420 White 4-1S 50 9-25 Va 321 650 1284 2600 Kowliang 4-17 95 9-22 1/20 27 16Q 540 3380 a 4-17 85 9-22 1/40 35 80 1400 3200 (t 4-17 100 9-22 V 415 I7.^n Sudan Durra. . 4-17 85 9-22 1/40 '33 81 1320 3240 Feterita 4-17 15 10-6^ Vi 21 202 c?l ROR tt 4-18 15 10-1 H 410 1230 1093 3280 Pink Kafir!!.'! 4-18 95 9_2Q 1/6 6?7 • 3762 Red " .... 4-17 90 Q_?Q V 628 ?^^-> White " .... 4-17 95 10-7 Va 240 630 f^60 2520 Jerusalem corn 5-27 70 10-6 V?> 140 210' 1120 16^0 1915 Standard milo 5-14 75 o_?6 V^ 487 3^06 t( tc 5-14 90 9-26 V 493 3Q4t D\''nrf m'lr,. . . r 1 -> rr 1 p -^-1 T / I-7/-1P? cirn tl a 5-14 95 9-21 V . - n^5 .... 4740 1 — Grain eaten by bird?. 2 — Calculated from preen weipht. Experimental Work in Dry-Farming 60 L TABLE LX — Continued Variety Date planted Stand Date har- vested Size of plot Yield per plot Yield per acre Grain Stover Grain StOVLT 1915 — Continued Dwarf VVIiite milo Dwarf White milo Feterita Siiallu Jerusalem corn Kowliang' .... Wliite Fv^aPir. . . Red " ". ". '. 5-14 5-17 5-14 5-14 5-17 5-14 5-14 5-17 5-14 5-13 5-17 5-14 % 95 95 85 95 95 95 95 95 55 ICO 100 70 9-21 10-25 9-26 9-26 10-24 9-26 9-26 10-24 9-26 9-24 10-21 9-26 Acres Ya Ya Ys Ys Ys Ys Ys Ya Ys Va Y3 Pounds Pounds 1230 1026' 570 465 456' 472 505 909' 709 3213' 2033' 1142 Pounds .... Pounds 4920 4104 4560 3720 3648 3776 4040 3635 5672 4284 6099 9136 -Calculated fiom green weight. The test in 1913 included eleven varieties. The most satis- factory 3-ield again was produced by Dwarf milo, White milo com- ing second. FiK. 36. — Dwarf milo, Sudan grass, and Sumac on bottom land, Prescott Dry-farm. 602 Bui^I^ETIN 84 Eleven varieties of grain sorghums were tested in 1914, the ex- cellence of Dwarf, Double Dwarf, and Standard milo, and Kowliang being attested. In 1915 nine varieties, all of which were used for ensilage, were tested, the biggest yield being produced by Red Kafir, White Kafir, and Dwarf milo. The variety test of grain sorghums is summarized in Table LXI. TABIvE LXI. SUMMARY, VARIETY TEST OF GRAIN SORGHUMS, PRESCOTT DRV-EARM Y e'd \)t r acre Variety 1912 1913 1914 1 1915 Average Grain 1 stover Grain ' Stover Grain Stover Grain Stover Grain Stover I P'uds ' P'llds P'>ids P'nds 1 P'nds P'tids P'nds P'nds P'nds P'nds Dwarf milo. . 916 3028 2496 3744 1560 2684 4950 1243 3601 Standard milo . 1480 2400 .... 3920 493 2107 Red Kafir " 4724 4660 .... 2512 • • . . 9136 .... 5258 Shallu 708 3316 176 428 • • . . < . . • - . . . 3684 295 2476 Blaciv-luillcd White Kafir 2058 • • • 2846 . . • • • . . . • . . , .... .... 2452 Jerusalem corn 268 1436 440 1644 1120 1680 > • • • 3776 457 2134 Feterita .... ■ . . . 300 304 588 2044 .... 4560 296 2303 Doiilile Dwarf milo 412 412 1440 2620 .... .... 926 1516 White milo.. 1932 2652 1082 2010 1507 2331 Sudan Durra .... 400 1200 1320 3240 860 2220 Kowlian? . . . 543 1830 647 2787 3837 397 2818 Pink Kafir... 6752 3762 .... .... 5257 White Kafir.. - • • • ■ • • 960 2520 5351 480 3935 Dwarf White milo .... .... 4512 .... 4512 TARLE LXII. MILO; DEPTH OF PLANTING TEST, PRESCOTT DRY-EARM Depth of planting Date planted Stand Date harvested Yield p er acre Variety Grain Stover Inches % Pounds Pounds 1914 Dwarf milo 6 5 5-14 5-14 80 90 10-2 9-27 1260 1292 3240 2584 <( li 4 5-14 85 10-2 1508 3132 a a 2 5-14 70 10-2 1104 2436 1915 Dwarf milo U li 6 5 6-5 6-5 95 95 9-29 9-29 .... 524 1098 (C 11 4 6-5 95 9-29 .... 224 It u 2 6-5 95 9-29 333 Hxi'l;RlMliXTAL W'ORK IX DrV-FaRMIXG 603 TAULK 1.XI1I. MiLo; TIAlli OF PLAXTIXG TEST, PRESCOTT DRY-F. \RM N'arieiy Date planted Stand Date har- Size ot - Yield per plot Yield per acre vested piot Grain stover Grain Stovei- Vc Acres Pounds Pounds Pvuiids Pounds 1912 Dwarf inilo. . . 4-10 4-16 9-18 10-7 200 518 800 2072 •• 5-10 10-16 Ya 229 757 916 3028 " 6-10 10-7 Ya 353 1412 1913 Dwarf niilo. . . 4-10 1/12 . . . i, 4-28 10-16 1/10 91 i84 910 1840 tt ti 5-10 10-16 3/40 150 150 2000 20C0 (( tt 6-10 10-16 3/40 60 118 800 1573 1914 Dwarf milo. . . 4/10 • • < . . . 1 .... tt tt 5-10 90 10-6 1/12 67 203 804 2436 tt tt 5-27 90 10-6 1/12 93 202 1116 2424 It ti ^10 95 10-6 1/12 55 240 660 2880 1915 Dwarf milo. . . 4/10 .... . . . : tt 5-10 95 9-26 1/20 i24 2480 it tt 6-10 70 9-26 1/20 91 1825 1— Killed by frost, replanted May 27. 2— Killed by frost April 27. Fig. 37. — Broom corn, Prescott Dry-farm. 604 Bulletin 84 To determine the optimum planting depth, four plots of Dwarf milo were seeded in May, 1914, and June, 1915, at depths ranging from two to six inches. The results, recorded in Table LXII, indi- cate the advantage of deep planting. To determine the most favorable time to plant, four plots of Dwarf milo were seeded in April, May, and June of 1912, 1913, and 1914, and three plots in 1915. The results, recorded in Table LXIII, indicate the desirability of planting early in May. MISCELLANEOUS CROPS Millet: A plot of Hog Millet was planted in 1912, yielding 2000 pounds of forage per acre. For data on millet, rape, and teosinte see Table LXIV. A small plot of Kursk millet, planted in 1913, yielded at the rate of 3600 pounds of hay per acre. In 1914 German, Kursk, and Hog millet were planted, low yields being obtained from all plots. Kursk and German millet were both planted in 1915, the larger yield being obtained from the latter. TABLE LXIV. VARIETY TESTS OF MILLET, RAPE, TEOSINTE, ETC., PRESCOTT DRY-FARM Variety 1912 Dwarf Essex rape. Hog millet Teosinte 1913 Kursk millet Teosinte Dwarf Essex rape. 1914 Teosinte German millet Kursk " Hog " 1915 Kursk millet German " Dwarf Essex rape. Turnips Buckwheat Date planted 5-16 5-20 5-24 7-8 4-26 7-8 4-10 4-10 7-10 4-17 6-5 6-5 5-14 7-6 7-6 5-15 Date 1 Size har- of vested plot Yield per plot 8-25 8-24 10-12 9-14 10-1 8-31 lO-l lO-l li^' Acres 1/20 9-23 10-22 I 1/30 Va Va Va Vs Va Va Vs Seed Pounds 20 5 Forage Pounds 350 100' 120 320 34 321 130 135 102' 142 325 c s Yield per acre Seed Forage Pounds 80 20 Pounds 1400 2000 3600 2560 136 1284 520 540 816 1136 i300 1 — Seed eaten by birds. 4 — Destroyed by rabbits. 5- 2— Frozen down in fall when 18 Inches high. 3— Failed -Killed by drought. Experimental Work in Dry-Farming 605 Rape: Dwarf Essex rape was planted in May, 1912, yielding 1400 pounds of dry forage per acre. Due to drought, a plot of rape failed in 1913. Dwarf Essex rape was again tested in 1915, yielding 1300 pounds of dry forage. Teosintc: A plot of teosinte planted in May, 1912, had attained a height of eighteen inches when it was frozen down in the fall. Teosinte in 1913 produced at the rate of 2560 pounds of dry forage per acre. In 1914 teosinte failed, yielding only 136 pounds of forage per acre. Turnips and Buckivhcat: Both turnips and buckwheat were tested in 1915, but were unable to withstand the ensuing drought. CULTURAL PRACTICES FOR DRY-EARMS Plowing: The best results on the Prescott Dry-Farm have been obtained from deep fall plowing, which assists soil readily to absorb precipitation in winter and early spring. Furthermore, the action of alternate freezing and thaAving puts soil in better tilth and assists in the release of plant food that otherwise would not be available. Fall plowing permits the farmer, with the advent of spring, quickly to establish a soil mulch with a minimum loss of moisture, and gives him ample time properly to prepare his seed bed for planting. Subsoiling is unnecessary, but the depth of plow- ing should be varied annually to prevent formation of a "plow sole." The depth of plowing should not be less than eight inches, and occasionally the soil should be stirred to a depth of ten or twelve inches. Cultivation: To insure crop production by dry-farming meth- ods, a mulch must be persistently maintained, and the most prac- tical method is cultivation. Variation in depths of cultivations tends to prevent formation of sub-surface crusts. Usually not less than four cultivations will be necessary effectively to control weeds and maintain a mulch. In addition, weeds should be kept out of the rows by hoeing, the entire moisture supply being needed by the plant. It is evident that much moisture will be saved and less labor made necessary if weeds are destroyed when they first appear. Because of the usual drought in June and July, lands should be kept especially clean and well mulched until precipitation 606 BuLIvETiN 84 is again abundant. It has been observed on the Prescott Dry-Farm that ahnost every crop which remained thrifty until the beginning of summer rains in July, yielded profitable returns. When work is well timed, a harrow satisfactorily maintains a mulch and destroys weeds on summer fallowed land. In one ex- periment a small area of summer fallowed land was divided into three portions, the first of which was harrowed when weeds were first showing; the second, six days later; and the third portion twehe days after harrowing the first. On the first plot fully 95 per cent of the weeds were killed, while on the second portion not to exceed 60 per cent, and on the third portion less than 25 per cent were destroyed. The imixjrtance of timely operations on dry-farms is not always fully realized. Cultivations delayed for even a day, especially dur- ing times of high temperatures and strong winds, may very se- riously hinder crop production. Planting should be done at times ^\']K■n the utmost advantage can be taken of precipitation imme- diately after it falls. Delayed plowing often causes failure, when timely tillage would have sufficed to insure a profitable yield. The influence of leguminous cover crops on the humus and nitrogen content of the soil is shown in Table LXV. While the data are meagre the value of cover crops is clearly indicated. Yields are t)ften reduced because of too thick seeding on drv- lAKLE LXV. IXl'LUJCXCr; of LIvr,i:MI.\()US COVER CROPS ox HUMUS AND XITROOEX, PRESCOTT DRY-FARM ORCHARD Plot Croi) 1st and 2nd ft. J3rd and 4th ft. Nitro gen Humus Nitro 1 gen Humus 1914; before planting legumes \o ] N'one ^4 .057 .066 .055 .059 .048 .041 .072 .098 % 1.46 1.40 1.21 1.68 1.33 1.62 1.38 2.91 % .039 029 .036 .031 .040 .050 ,035 04^ % 048 •• 7 (( 1 08 " 3 a 0.85 4 << 1 38 1915; after cover crops were turned under No. 1 " 2.: " 3 " 4 Canada Field peas. . . Black-eyed covvpeas.. Tepary beans Colorado Stock peas 2.07 1.12 0.80 2.00 ExPKKiMi-:.\ TAi. Work in I^ry-Farming r)07 farms. The most satisfactor}- rates of seeding on dry-farms in the Prescott vicinity are stated in Table LXVI. TABLK LX\I. SUGGESTED RATES OF SEEDING ON DRY-EARMS Pounds per Acre Milo, Kafir, and feterita 3 to 5 Sudan grass 8 to 10 Club-top, sumac, and Amber sorghum 2 to 7 Large beans ( Pinks, etc. ) 9 to 12 Small beans (Teparies and Navies) and peas 8 to 10 Wheat and small grains 25 to 35 Millet and similar crops 10 to 12 Potatoes (cuttings) 375 to 600 SIEOS AND ENSILAGE Botli pit and above-ground silos are in use on the Prescott Dry- faim. The pit silo, twelve feet in diameter and twenty-seven feet deep, was constructed at a cost of approximately fifty dollars, ex- clusive of labor. A collar, six inches thick and three feet high, the bottom of which is approximately two feet beneath the surface of the ground, was poured first. The pit was then dug to the desired depth and a thin cement wall was poured when the silo was filled in the fall, the fresh ensilage being used in place of a scaffold. Later construction has indicated the desirability of plastering rather than pouring the tinderground wall. The above-ground silo, 12x20 feet, cost $2.75 for each foot in height. Silos are virtually necessary to dry-farmers of the region. Kn- silage may be fed to horses, cattle, sheep, and swine, any of which may be maintained during times of scarcity of better adapted feeds. A great advantage lies in the fact that crops, raised during a suc- cessful year, may be stored in silos and utilized in later years of scarcity. Ensilage has been kept for several years without appar- ent depreciation, aside from spoilage on the top layer, which takes place very quickly after the ensilage is made. Satisfactory crops for ensilage are mixtures of Cltib-top sor- ghum and Dwarf milo, the former producing a heavy tonnage and the latter a large yield of grain. The importance of quantity rather than quality must not be overestimated, however, as it is probable that from 50 to 75 per cent of the value of most ensilage is in the grain content. Therefore, attention should be paid to the state of maturity of the grain of the ensilage crops. The seed should be as 608 Bulletin 84 nearly ripened as possible, while the stalks and leaves are still succulent. A combination of dry-farming with range stock raising appar- ently offers the largest profits of any system of dry-farm manage- ment capable of adaptation to conditions similar to those of the Prescott Dry-Farm. Dry-farmers with full silos and range stock have a decided advantage over stockmen who depend wholly on the range, or dry-farmers who depend upon crop sales for cash. With this system of management, such crops as beans and potatoes may be grown to sell for cash to shorten the intervals between times of financial income. It is important that dry-farmers realize the limited production of a unit area of their land, and that their farms are ample in size. Table LXVII states capacities of silos of various sizes. T.\|;LI". I. XVII. CAPACITV OF SILOS* Inside In.side Cajfacity Number of Mini mum re- diameter height feeding days moved daily Feet Feet T071S Pounds 8 20 17 121 280 24 20 142 24 34 130 10 28 42 160 525 32 51 200 26 55 132 12 30. 67 177 755 32 74 195 30 91 175 14 32 100 193 [030 36 lis 228 32 131 181 16 36 155 230 1340 40 180 270 36 196 20 40 44 281 320 *From Circular No. IT, Extension Sei\ice, Univer.sity of Arizona, by W. A. Barr. THE SULPHUR SPRING VALLEY DRY-FARM The Sulphur Spring \'alley Dry-farm'* established by the Ari- zona Agricultural Experiment Station in August, 1913, contains 160 acres near Cochise on the main line of the Southern Pacific Railroad, which crosses the northwest corner. The soil is a red loam of varying structure with occasional *Por map of Sulphur Spring Valley Dry-farm see Twenty-eighth Ann. Rept. Aiiz. Asrric. Kxp. Sta.. p. 400. Experimental Work in Dry-Farming 609 patches of gravel and coarse sand, except where two swales cross the farm. In these a darker, finer, and more productive soil is found. A stratum of "caliche" underlies the entire farm at a depth of one to four feet. Mechanical and chemical analyses are reported iii Tables XVI to XIX inclusive. About seventeen acres in the northeast corner of the farm had been cultivated for several years, a good crop of beans having been grown in 1912. The remainder of the farm was covered with a luxuriant growth of native grasses, especially grama, galleta and bluestem, and yucca. About twenty acres in the northwest corner of the farm and thirty in the southwest corner were broken in the winter of 1913-14; since then the remainder of the farm has been used for pasture. The need for data having immediate, practicable application was manifest. Accordingly, experimental work done on the Sul- phur Spring Valley Dry-farm has been limited to investigations TABLE LXVIII. ] VIOISTUI IE DETE RMINAl ^lONS, S ULPHU K bi'KlJN (j V. \LLEY DRY-FARM Location 1st ft. 2nd ft. 3rd ft. 4th ft. 5th ft. 6th ft. 7th ft 8th ft. % % % % % % % % January11,1915 Boring 1 . . 18.5 17.5 13.5 12.8 13.4 13.1 10.7 9.1 2.. 16.6 15.1 14.8 11.2 13.1 10.2 9.0 5.5 3.. 12.9 12.1 15.9 16.3 16.8 18.8 16.9 10.2 4.. 11.3 15.5 15.7 13.0 12.9 11.5 8.0 5.. 11.8 13.1 11.8 9.35 12.3 7.11 9.3 *6.'i5 6.. 14.6 13.8 15.0 12.5 14.3 11. 1 10.2 8.9 7.. 15.6 18.2 15.3 12.7 11.8 12.1 10.5 6.8 10.. 8.0 11.3 13.7 15.7 9.9 9.5 18.5 9.5 July 8-11, 1915 Borins' 1 . . 5.8 9.5 8.7 11.7 10.1 10.8 9.6 9.9 2.. 11.7 14.4 14.6 13.0 13.4 9.6 7.0 7.1 3.. 7.3 13.2 17.0 17.2 12.4 9.8 14.1 10.2 • 4.. 8.4 15.3 11.2 14.2 14.9 11.8 11.4 11.5 5.. 9.8 13.8 11.7 13.2 17.3 12.9 14.9 7.0 6.. 10.3 11.5 15.2 15.2 15.6 12.7 .... 7.. 9.0 13.8 14.1 13.4 16.2 13.0 • ■ • • 10.. 8.6 12.3 17.3 12.0 12.9 14.6 15.9 127" July 1-9, 1916 Boring 1 . . . 2... 9.8 12.0 11.4 9.5 9.4 9.8 8.9 7.9 10.5 10.7 10.3 6.7 5.9 8.1 5.1 7.3 3... 11.8 11. 1 4.8 5.7 4.9 10.6 8.8 7.8 4... 11.8 13.2 5.9 8.1 6.1 9.0 13.2 1 ^ 11.3 5 .. 10.4 8.6 4.1 4.0 7.5 7.8 1 8.8 6.6 6... i 13.6 10.2 7.8 6.2 6.9 7.5 9.1 10.2 8... 8.9 8.5 8.0 7.2 8.2 8.5 5.2 4.9 9... 1 6.1 5.5 3.9 3.6 2.1 5.1 7.5 10.4 610 Bulletin 84 concerning conservation of moisture, variety tests, tillage methods, and the most favorable dates, rates and methods of planting; the utilization of occasional iloodwaters and supplemental irrigation by pumped waters; and the study of livestock management in its re- lation to dry-farming. Moisture determinations were made on a great number of soil samples taken on various dates at depths of eight feet or less. Table LX\'1II records the results. .\LI'ALK.\ Turkestan alfalfa was planted in a small plot south of the dwelling-house, October 12, 1914. It was drilled thinly to a depth of four inches, in rows two feet a])art, in a well-prepared seed bed. The soil was nut uniform and it is interesting to note that the alfalfa came up very readily through the deep mulch of the loamy soil while in the sandy soil, where the mulch was somewhat settled, the stand was poor. About sixty per cent of a normal stand emerged, but winter killing and injury by rabbits reduced the stand by half. The crop was not harvested, but in August, 1915, the yield of seed was carefully estimated as 150 pounds per acre. From this limited trial it appears that alfalfa, grown in rows and culti- vated, will return a slight income from the production of seed. 1 5 KAN'S Five varieties of beans were j^lanted in May, and six in July, 1914. See Table LXIX. The seed bed for the May plantings was irrigated by laying out small furrows three feet apart, after which two inches of water was run in each furrow. Beans were then ])lanted in the mud and covered to a depth of three inches with dry soil. Prompt germination and rapid growth followed, but, since the beans later appeared to suffer from drought, they were given a three-inch irrigation on June 26. The rainy season began early, and no further irrigation was given except a flood, about four inches deep, Avhich passed over the field July 2. The vines grew to a height of approximately four feet, but blossomed sparingly. ExpKRiMHNTAL Work in Drv-Farming 611 TABLt; I.XIX. VARIKTV TEST OE IJIjAXS, SULPHUR SPRING VALLEY DRY-FARM Date Date Yield per acre Variety planted Stand harvested - Beans Straw % Pounds Pounds 1914 Pink 5-29 90 10-17 484 324 Yellow Hopi 5-29 90 10-1 408 1296 White •• 5-29 5-29 5-29 7-20 7-24 90 95 85 95 90 10-16 10-16 iO-16 10-1 10-12 624 672 576 660 185 1200 Red •' : 1911 Hopi Liiiia 912 Dwarf Valentine 528 Trammel 100 >v 7-20 7-24 7-27 59 85 30 10-1 10-19 9-25 500 100 24 White Navv 150 Small Spanish 72 Pink 7-23 80 9-25 204 156 White Teparv 7-18 1 tt t* 7-17 7-17 7-17 7-18 80 80 80 80 io-i 10-6 10-7 10-1 i68 180 252 612 200^ .< 180' ii ti 224^ i. a 576= 1915 Yellow Casa Grande 7-20 80 11-1 154 396 Casa Grande 7-20 90 11-1 528 1584 Pink 7-21 80 11-16 176 396 Colorado Pinto 7-20 95 11-11 308 1232 Bates' 7-20 7-20 93 95 11-11 11-1 264 484 1276 Lady Washington 1276 Red Hopi 7-20 85 11-11 704 1320 White " 7-21 7-21 70 70 10-22 10-22 484 1144 Yellow Hopi Bayou 7-20 7-21 90 70 11-1 10-22 352 308 880 White Navy 528 T. I. No. 6 7-21 50 10-22 132 264 I. I. No. 7 7-21 40 10-22 88 352 I. I. No. 8 7-21 15 10-22 22 66 Cream Aztec 7-11 7-17 ioo 9-19 10-6 75 720 Tepary ii 7-17 7-19 1 100 90 10-6 10-22 784 167 Pink a 7-19 7-21 90 1 75 1 10-22 I 1 1-22 249 Hopi Lima 720 L L No. 9 7-20 11-1 66 220 Dwarf Valentine 7-20 70 11-1 280 640 Black Prolific 7-20 7-20 40 60 11-1 11-20 66 110 176 Small Spanish 242 Tepary 5-1 1 1 — Destroyed by rabbits. 2 —Seeded 6 lbs. per a ere. 3— See ded 8 lbs. per acre, 12-inch rows. 4 — Seeded 12 lbs . per acre, 12-inch re ws. 5 — See ded 8 lbs. per acre, 36-inch rows. 6 — Destroyed b> ■ grasshopp ers. All of the varieties except Hopi Lima were blighted between vSeptember 5 and 20. Pink beans apparently were least, and White Hopi most resistant. 612 BuLi^ETiN 84 The best yield was obtained from the Red Hopi variety, which produced 672 pounds of beans and 1911 pounds of straw per acre, while the smallest yield was produced by Yellow Hopi beans, which returned 408 pounds of beans and 1296 pounds of straw per acre. Hopi limas grew vigorously throughout the season and set numer- ous pods, usually containing two, occasionally one or three beans each, and yielded at the rate of 560 pounds of beans and 912 pounds of straw per acre. The results obtained from July i)lantings were not so satisfac- tory, damage by grasshoppers and rabbits materially diminishing yields. The Dwarf Valentine variety, yielding 660 pounds of beans and 528 pounds of straw per acre, gave best results. One plot of White teparies seeded at the rate of eight ])()un(ls per acre produced 612 j)ounds of beans and 576 pounds of straw per acre, and a plot of Trammell yielded 500 pounds of beans. Si.x plots of White teparies were planted July 17 and 18 at varying rates, and consequent yields indicate the desirability of thin seeding. The better yield from the plot seeded in thirty-six inch rows at the rate of eight pounds per acre is partly due to more fa- vorable soil and moisture conditions. Twenty-one varieties uf beans were tested in 1915. Most of Fig. 38. — Dry-farmed milo, melon.s, and bean.=!, near Cochise, Arizona. ExfERiMiCNTAiv Work in Dry-Farming 613 the planting was delayed until July 17 because of the lateness of the summer rainy season. To destroy the grasshoppers which infested the field, a poi- soned bran mash* was scattered broadcast before the beans came 1']). The result was quite thorough destruction of the insects, but other grasshoppers came in from the outside and did considerable damage to the crop. The highest yield in 1915 was obtained from two plots of teparies which produced 720 and 784 pounds of beans per acre re- spectively. Of the larger varieties Red Hopi again led with a yield of 704 pounds per acre. Casa Grande came next with 528 pounds per acre, and White Hopi and Lady Washington were in third place v.ith a yield of 484 pounds per acre, each. Hopi lima beans did not mature because of the short growing season remaining after sum- mer rains began. The vines grew well and were heavily loaded with green pods when frost came. TAxil^K LXX. brans; time of planting TI5ST, SULPHUR SPRING VALLEY DRY-FARM, 1915 Date planted stand Date harvested Yield per acre Variety Beans straw Tranitntll 4-20 5-10 6-15 7-15 % 50 40 5 9-8 9-8 10-10 Pounds 88 132 33 Pounds 286 308 .. 55 a 1 1 — Destroyed by grasshoppers. Trammell beans were used in a test to determine the most fa- vorable date of planting. Plots were seeded April 20, May 10, June 15, and July 15. See Table LXX. The planting of May 10 gave the best returns, yielding 132 pounds of beans per acre. The July 15 plot was destroyed by grasshoppers. Data obtained in this test are insufficient to be considered as an absolute indicator of the best time for planting. To determine the optimum rate of seeding, six plots of Dwarf Valentine and White teparies were planted at rates varying from four to fourteen pounds per acre. See Table LXXI. The teparies *The poisoned bran mash was made according to the following formula: Paris green 1 pound Water 2/2 f Bran 25 pounds Corn syrup 1 Q'^'art Lemons i 614 Bulletin 84 were entirely destroyed by rabbits, and the indications from the re- maining plots, while indefinite, seem to favor a rather thin planting. TABLE LXXI. beans; RATE OE SEEDING TEST, Sri.riUR STRING VALLKV DRV-I-ARM. 1915 Date Stand Date Yield per acre Rate of Variety planted harvested seeding per acre Beans Straw Poiiiiiis Po II >i (is Foil fids Dwarf Valentine. . 7-30 Good 11-18 220 110 4 7-30 11-18 220 220 6 7-30 11-18 260 198 8 7-30 11-18 220 308 10 7-30 11-18 176 198 12 7-30 11-18 260 220 14 To determine the most i)ractical)k' si)acing of ])lants li\-e ])lots C'f Casa Grande beans were planted July 20, 1915. Rows were three feet apart in all plots, and plants were thinned to thirty-six, twenty-four, twelve, and six inches apart. One check plot was left without thinning. Table l.XXII records the results, the best yield being obtained from the j^lt^t that was not thinned. Damage bv grasshoppers, however, so hampered the growth of beans in this test that data obtained are' not especiallyi valuable. Fig. 39. — Bean harvester in use on Sulphur Spring Valley Dry-farm. ExpCRiMKxTAL Work in Drv-Farming 615 TAULK LXXII. 1:i:aNS; SPACING TKST, SULPHUR SPRING VALLEY DRV-PARM, 1915 Date Date 1 hat- Yield per acre j Spacing Variety planted Stand I vested Beang straw Plants 1 Rows '-f. Pounds Pounds Indies Inches Casa Grande. . 7-20 40 11-16 88 264 36 36 i< a 7-20 40 11-16 88 264 24 36 H ti 7-20 40 11-16 110 352 12 36 a a 7-20 40 11-16 110 308 6 36 li a 7-20 60 11-16 132 352 Not thinned 36 CORN The winter of 1913-14 was very dry, and, in spring, there was insufficient moisture in the soil to warrant planting, which accord- ingly, was delayed until the rainy season commenced early in July. The seed bed had been prepared by plowing in the fall of 1913, and by frequent harrowing. Part of the field had been in beans in 1912, and the remainder was newly broken native sod. Experimental work with ct)rn in 1914 was confined to variety testing. All plots were grown under practically the same conditions, with minor va- riations in soil quality, and were cultivated after every shower of importance, four or five times in all. In Table LXXIII figures under "grain" represent the unshelled corn and "stover" the sun- dried plant after the grain had been removed. The dry condition of the ground in September, 1914, hastened maturity of most of the corn varieties except Mexican June, which instead of ripening, apparently became inactive until the middle of October, when the moisture condition again became favorable. Re- newed growth at this time prevented maturity until the crop was killed by frost. Half Dent Drought Proof, White Australian, and one plot of Strawberry corn were in shallow and somewhat gravelly soil and were most aft'ected by drought, a large percentage of stalks being killed outright. See Table LXXIII. The best plots of White Flint, Hickory King, and Strawberry received a six-inch flood July 2. In 1915 the highest yield was obtained from a plot of Mexican June, while Saquai)u (an Indian variety). White Wonder, and Mo- have were the next best varieties. Since 1915 was a rather dry year, there were large numbers of barren stalks in plots of the larger, American varieties : for exam])le. 20 per cent of the stalks in 616 Bulletin 84 TARLE LXXllI. VARIETY TEST OP CORX, SULPHUR SPRING VALLEY DRY-FARM Variety 1914 Yellow Hopi Blue '• Mixed " White " White Flint tt it Mexican Yellow Flint.... Pincdale Sacaton White Australian Takoorze Hickory King Mexican June Colorado Yellow Dent... Yellow Dent White " Half Dent Drought Proof Reid's Yellow Dent Maul's Early " Mohave Strawberry It it Learning White Pearl Iowa Silver Mine Brazilian Flour Corn Palakai Sylvia's Early Pop Bloody Butcher Pima Ensilage White Wonder tt tt Swadley Innominata Saquapu , Heroosquapa White Koescha Kai Mexican Black Sweet 1915 Adams Sweet Mexican Black Sweet Swadley Colorado Yellow Dent.... « « it Date p. anted Stand 7-1 Q 7-19 7-24 7-24 7-29 'A 7-18 61 7-16 72 7-16 65 7-18 ' 77 7-17 57 7-18 , 68 7-16 44 7-9 2 7-16 72 7-14 44 7-18 85 7-20 90 7-16 83 7-15 65 7-13 52 7-14 50 7-9 68 7-6 18 7^ 78 7-18 64 7-16 66 7-6 36 7-14 69 7-20 79 7-16 71 7-10 66 7-13 57 7-17 70 7-17 90 7-18 44 7-15 86 7-16 56 7-7 77 7-7 79 7-7 79 7-11 80 7-21 90 7-18 80 7-16 79 7-16 88 7-16 89 7-17 52 50 70 90 Date harvested Yield per acre Grain 10-15 10-16 10-28 11-5 10-15 11-16 11-5 10-19 10-15 10-21 10-19 11-27 11-27 11-19 11-28 11-28 11-5 11-4 11-27 10-21 11-27 11-18 11-18 11-19 11-27 11-25 11-28 11-28 11-5 11-16 11-27 11-19 10-28 11-27 11-17 11-25 10-19 11-16 11^ 11^ 11-4 11-4 11-12 10-31 11-8 11-15 Pounds 59 297 748 137 384 3149 308 39 352 30 616 2475 220 168 440 420 83 2,7 450 374 1364 15 345 2112 560 864 875 315 154 455 525 140 522 2788 1640 590 754 480 528 37? 195 89 360 748 stover Pounds 381 810 1672 650 1472 6231 1144 99 660 1050 1144 3825 2640 434 1705 1650 705 161 1710 638 1672 225 900 2420 1372 2376 1505 2135 506 816 2375 1500 1650 1791 7.W» 3715 2270 1508 4S0 616 806 897 I 1 I 1040 1276 1 — Failed to eniei-ge. Experimental Work in Dry-Farming 617 TABLE Lxxiii — Continued Date planted stand Date harvested Yield per acre Variety Grain stover 1915 — Continued Sacaton Mexican June 7-26 5-25 5-25 4-5 5-25 5-22 5-22 4-19 5-20 5-20 5-22 5^ 8-2 7-29 8-2 8-2 7-29 5-4 5-19 7-19 7-28 5-15 5-19 5-4 5-19 5-20 4-10 4-19 5-12 5-25 4-16 5-15 7-22 4-16 5-15 7-22 4-16 5-15 7-22 4-16 5-15 7-22 4-16 5-16 7-22 4-18 5-16 7-22 '/o 50 80 85 100 85 70 85 85 90 80 85 90 90 90 60 85 75 85 85 80 '80 80 90 85 80 95 80 90 85 100 80 100 100 60 100 95 50 100 100 50 100 100 50 98 80 25 100 10-31 10-12 10-12 9-23 10-8 10-10 10-18 9-22 9-28 10-12 9-16 8-30 11-15 11-10 11-10 11-15 11-10 9-11 9-16 11-12 11-15 9-16 9-28 9-22 9-14 9-28 8-30 9-8 9-22 9-8 9-21 9-21 11-9 9-21 9-21 11-2 9-21 q_9i 11-2 9-25 9-21 10-24 9-21 9-21 10-24 10-17 9-21 11-11 Pounds 80 1596 891 105 704 297 576 572 704 336 1012 484 '660 484 '264 660 484 1056 '528 704 608 528 360 226 136 462 1166 2490 1452 3802 1612 1164 894 500 160 394 94 600 1298 176 700 764 25? 1064 Pounds 96 Joe Wanderer 4004 Joe Wanderer Knsilage 2595 4528 A 1463 Bloodv Butcher 5280 Kansas White 1628 Queen of Nisna Pride of Salome Mohave White Cap Pop 1716 714 1364 1518 1980 1100 White Australian Reid's Yellow Dent Maul's Early " Diamond Joe a it 616 1936 440 2992 2332 White Wonder Crosby Sherrod Ranch White 4004 2176 912 1408 <( It 1568 Heroosquapa Freed's 792 450 Strawberry White Pearl Hickory King Saquapu 1916 Mexican June 847 1259 1716 3586 2207^ it n 1209' 3165' White Flint (t i( 2033' 998' t( it 13QS' 1764' it 239' 2514' White Hooi 220» It It 54' 11 ti 1413' Mohave ti 637» 87' « 2840' Papago Sweet It tt 54^^' H It 2309= 2 — Calculated from green weight. 618 Bulletin 84 the Mexican June plot were barren, 60 per cent in the Joe Wanderer plot, 27 per cent in the White Ensilage plot, and 30 per cent in the Bloody Butcher plot. Summer rains in 1916 came early and were well distributed. The superiority of White Flint, Mexican June, and Mohave was again demonstrated, while Papago Sweet, tried for the first time on the Sul])hur Spring \'alley Dry-farm, produced a good yield. In Tal)le LXXIW the average yield per acre of plots of all varieties for each year is shown, and in a separate column fields of all varieties for the three-year ])eriod are averaged. White Flint has been the most productive. White Wonder second. Hickory King third, and Mexican June fourth. TAliLK LX.\I\' . SUM.M.XkV, V-Vkiri-IY TEST Ol- CORN . SULI' IL'K Sl'K IXC, VALLEV DRY-FARM Yield per acre Variety 1914 1915 1916 1 1 Average Grain stover Grain Stover Grain Stover Grain Stover P'Oinids Pounds Pounds Pounds P7unds Pounds P?unds Founds ^'ollovv ] fopi. . . 59 381 59 381 r.lue " ... 297 810 .... .... 297 810 Mi.xcd " ... 748 1672 748 1672 White " ... 137 650 363 562 250 606 White Flint 1766 3851 • > • • 2193 1478 1979 2664 Mexican Yellow Klint 308 1144 308 1144 Sacaton 352 660 80 i 96 216 378 Pinedalc 39 99 1 39 99 W h i t e Aus- ' tralian 30 1050 484 616 . 257 833 Takoorze 616 1144 616 1144 Hickory King. . 2475 3825 462 1716 1468 2770 Mexican Jime. . 220 2640 1596 3732 1314 2i94 1043 2855 Colorado Yel- low Dent .... 168 434 554 1158 .... 361 796 Yellow Dent . . . 440 1705 440 1705 White " ... 420 1650 • • . > 420 1650 H a If D e n t Drou2:ht Proof 60 433 60 433 Reid's Yellow Dent 450 1710 . ■ . > 1936 .... 225 1823 Maul's Early Dent 374 638 264 440 319 539 Mohave '364 1672 1012 1364 '7i8 iiss 1031 1408 Strawberry . . . 824 1182 226 847 ■ ■ • > 525 1014 Lcamin.e 560 1372 .... 560 1372 White Pearl... 864 2376 'i36 ; 1259 .... 500 1817 Iowa Silver Mine 875 1505 1 .... 875 1505 ExriiRiMENTAL Work in Dry-Farming 619 TABLE Lxxiv — Continued Yield per acre Variety lyii Grain Stover Brazilian Flour Corn Palakai Sylvia's Early Pop Bloody Butcher Pima Ensilage White Wonder Swadley Innominata • • • Saquapu Heroosquapa • • Koescha Kai . . Mexican Black Sweet Adam's Sweet Joe Wanderer Kansas White. . Queen of Nisna Pride of Salome White Cap.... Diamond Joe- • Crosby Sherrod Ranch White . . Freed's Papago Sweet Pounds 315 154 336 455 525 140 522 2214 590 754 ,480 528 372 195 498 572 704 336 484 572 528 656 360 lyio 191G Grain Stover Founus 2135 506 816 2375 1500 1650 1791 5538 2270 1508 480 616 806 897 3299 1628 1716 714 1518 2662 2176 912 1488 450 Pounds 576 660 500 1056 44 1166 528 Grain PoUUaS 1980 5280 1100 2995 4004 140 3586 792 Pounds Stover Pounds Average Grain Stover Pounds Pounds 518 693 1506 1102 315 154 336 227 550 400 511 1635 317 754 823 528 372 97 498 572 704 336 484 572 528 656 439 693 2135 506 816 2177 3390 1375 2393 4771 1205 1508 2003 704 806 448 3299 1628 1716 714 1518 2662 2176 912 1488 978 1102 To determine the optimum time to plant, White Wonder corn was seeded on six dates, as shown in Table LXXV, ranging from March 29 to August 15. A perfect stand was secured in the March planted plot, the soil being moist to within an inch of the surface. In April and May the corn was planted three and one-half inches deep. In June and July a heavy sub-mulch crust was formed, which was broken with a 6-inch pony plow so that the seed might be planted in moist soil. The resulting stand was poor. A shower, occurring just after the July planting, formed a crust on the sur- face of the soil, which prevented many plants from coming up. The August planting was too late to allow the corn to mature. Table LXXV indicates the desirability of early planting in spite of the drought usually encountered in May and June. To determine the optimum rate of seeding, six plots of Mixed 620 Bulletin 84 TABLE LXXV. corn; TIME OF PLANTING TEST, SULPHUR SPRING VALLEY DRY-FARM, 1915 Variety Daie plantfd Stand Date harvested Yield per acre Grain Stover White Wonder. Vo Pounds Pounds 3-29 lUO 9-4 880 2338 4-20 90 9-14 792 3210' 5-10 90 9-14 880 3153' 6-15 25 10-16 286 1584 7-15 40 10-25 440 792 8-15 2 1 — Calculated from green weight. 2 — Failed. Hopi corn were planted on Jtily 29, at rates varying from three to ten pounds of seed per acre. The results, recorded in Table LXXVT, substantiate the popular opinion that thin seeding on dry farms is the most profitable. TABLE LXXVI. CORN ; RATE OF SEEDING TEST, SULPHUR SPRING V.XLLEY DRV-F.\RM, 1915 Date 1 Date Yield per acre Rate of Variety- planted Stand harvested seeding Grain Stover per acre Pounds Pounds Pounds Mixed Hopi 7-29 Good 11-21 792 1144 3 7-29 11-21 1056 1540 4 7-29 11-21 858 i 1254 5 7-29 11-21 814 1122 6 7-29 11-21 792 1232 8 •".... 7-29 11-21 770 1254 10 Table LXXVI I records data obtained from a depth of planting test in which six plots each of White Wonder and White Hopi corn were .seeded on July 31, at depths varying from two and one-half to seven and one-half inches. While White Wonder did not mature, the indications from both varieties are that corn should be planted deeply. The optimum depth, of course, depends upon the moisture content of the soil, experience on the Sulphur Spring Valley Dry- farm indicating that corn should be planted about two inches into moist soil under the dry mulch. When corn is planted early, level culture is preferred, but with later plantings, in the dry months of May and June, listing is the better method. An experiment in the spacing of corn plants, somewhat similar to that recorded in Table LXXVI, is noted in Table LXXVIIT. Experimental Work in Dry-Farming 621 TABLE LXXVII. CORN ; DEPTH OF PLANTING TEST, SULPHUR SPRING VALLEY DRY-FARM, 1915 Date Date harvested Yield per acre Depth ol' Planting; Variety planted stand Grain Stover % Pounds Pounds Inches White Wonder. . 7-31 100 11-16 2904^ 2/ 7-31 100 11-16 3234' 3/2 ii *i 7-31 100 11-16 3102' 4/2 li *i 7-31 100 11-16 5214' 5/a il U 7-31 100 11-16 4444' 6/2 ii tt 7-31 100 11-16 3894' 7/2 White Ilupi 7-31 95 11-16 m'z 704 2/2 H *> 7-31 95 11-16 1056 792 3/2 t< ki 7-31 95 11-16 1100 1012 4/2 ii tt 7-31 95 11-16 880 748 5/2 a ti 7-31 95 11-16 924 ■ 660 eY2 ii *i 7-31 95 11-16 836 572 1V2 1 — Immature. Five plots of White Flint corn, planted May 15 in rows thirty-six inches apart, were thinned to distances varying from twelve to thirty-six .inches apart in the roAv. One plot was not thinned, serv- ing as a check. Table LXXVIII indicates the importance of not having dry-farmed plants too close together. TABLE LXXVIII. CORN ; SPACING TEST, SULPHUR SPRING VALLEY DRY-FARM, 1915 Date Date Yield per acre Spacing Variety planted naivesieu . Grain Stover Plants Rows White Flint.... It 11 5-15 5-15 5-15 5-15 5-15 9-28 9-28 9-28 9-28 9-28 Pounds 768 744 1104 1056 696 Pounds 1488 1608 1152 1152 964 Inches Not thinned 12 18 24 Inches 36 36 36 36 36 From the first the difficulty of moisture conservation in south- ern Arizona has been manifest, and opinions regarding the amount of cultivation necessary vary greatly. Table LXIX records a test in which six plots of Ranch White corn, planted July 31. were cul- tivated eight times or less. WHiile moisture is not easily conserved, the results indicate the desirability of frequent cultivations, best yields having been obtained from the plot cultivated five times. To determine the advantage of the use of organic fertilizers, two corn plots were covered with barnyard manure early in the 622 Bui,]:.e;tin 84 TABLE LXXIX. CORN ; CULTIVATION TEST, SULPHUR SPRING VALLEY DRY FARM, 1915 Variety- Date planted Stand Date harvested Y'ield per acre Cultiva- tions Grain Stover Ranch White a it 7-31 7-31 7-31 7-31 7-31 7-31 % 95 90 90 95 95 90 11-13 11-13 11-13 11-13 11-15 11-15 Pounds 880 880 880 968 1408 968 Pounds 2794 2420 3520 3740 5984 3696 0 1 2 3 I spring of 1915, at the rate of tw^elve loads per acre ; a crop of winter vetch, yielding about five tons of green forage per acre, was plowed under in June on two other plots ; and an additional two plots were left without fertilizer. An Indian variety. White Hopi, and an American variety, White Cap, were planted on July 21 under the three conditions of soil treatment. A flood about three inches deep preceded the planting five days, and a uniform stand and rapid growth were noted in all plots. Table LXXX records the results, which favor green manuring. TARLE LXXX. CORN ; FERTILIZER TEST, SULPHUR SPRING VALLEY DRY-FARM, 1915 Date Date Yield per acre Variety planted stand har- Fertilizer per acre vested Grain Stover % Pounds Pounds White Hopi . . . 7-21 90 10-18 \232 1848 Twelve loads manure