THE UNIVERSITY OF ILLINOIS LIBRARY ir UNIVERSITY OF ILLINOIS Agricultural Experiment Station BULLETIN No. 193 SUMMARY OF ILLINOIS SOIL INVESTIGATIONS BY CYRIL G. HOPKINS, J. G. MOSIEE, AND F. C. BAUEB URBANA, ILLINOIS, DECEMBER, 1916 SUMMARY OF BULLETIN No. 193 1. The Illinois Agricultural Experiment Station has been conducting exten- sive investigations upon the improvement of Illinois soils for the past fifteen years by means of a systematic soil survey, chemical analysis, and culture experiments. Pages 451-462 2. Field investigations have been conducted upon fifty experiment fields located upon representative types of soil in various parts of the state. Thirty-nine of these fields are in operation at the present time. Pages 454-459 3. Illinois soils exist in fourteen great soil areas, as shown on the colored map. Pages 463-464 4. In the counties covered by the first ten soil reports, 62 individual soil types have been discovered. These types are extremely diverse and for con- venience are grouped into six classes; namely, prairie, timber, terrace, ridge, swamp and bottom-land, and residual soils. Pages 464—465 5. The fertility invoices of the individual soil types show a great variation in the content of the essential plant-food elements. Illinois soils may be deficient in one or more of five plant-food elements; namely, nitrogen, phos- phorus, potassium, calcium, and magnesium, — and they may be either acid or alkaline. Thus the problem of maintaining the fertility of the soil is sometimes complicated, tho usually limited essentially to the application of limestone and phos- phorus and the turning under of nitrogenous organic matter. Pages 465-467 6. As a rule, the results of the field experiments harmonize with the informa- tion given by the chemical composition of the soil. They have shown: (1) that the maintenance of organic matter and nitrogen is the greatest practical problem of the Illinois farmer; (2) that phosphorus is the one element of plant food that is most universally deficient; and (3) that limestone must be supplied in abundance to many soils before they can be permanently improved. Pages 467-483 7. On the ordinary corn-belt soil, proper treatment has produced a total value for one rotation (1911-1914) of $98.58, as contrasted with $65.00 where no treatment was given. One dollar invested in rock phosphate has paid returns as follows: first rotation, $1.18; second rotation, $1.62; third rotation, $2.70. Pages 473-475 8. Southern Illinois prairie land has been improved by proper soil treatment so that the total increase over untreated land has been 207 percent. Page 477 9. On peat soil, potassium has increased corn yields by more than 30 bushels per acre. Page 482 10. On sand soils, during six years the value of the crops per acre has been increased $73.37 by nitrogen and only 22 cents by phosphorus in addition. Page 482 11. Every farmer should practice a high-grade system of permanent agricul- ture. This is made possible by good crop rotation and the application of materials economically supplementing soil deficiencies. Page 483 Available publications relating to Illinois soil investigations. Page 484 SUMMARY OF ILLINOIS SOIL INVESTIGATIONS BY CYRIL G. HOPKIXS, CHIEF ix AGRONOMY AND CHEMISTRY J. G. MOSIER, CHIEF IN SOIL PHYSICS, AND F. C. BAUER, ASSOCIATE IN SOIL FERTILITY The wealth of Illinois is in her soil, and her strength lies in its intelligent development. — DRAPER. The purpose of this bulletin is to summarize the results of the soil investigations which have been carried on by the Illinois Agri- cultural Experiment Station, in order that the farmers and landown- ers may know of the progress being made, and thus hasten the adop- tion of systems of farming that will increase and permanently main- tain the productive capacity of Illinois soils, instead of decreasing their fertility, as is done under the most common practices. NATURE AND EXTENT OF INVESTIGATIONS The Illinois Agricultural Experiment Station began to investigate the soils of the thirty-six million acres of land within the borders of the state in 1901, with an appropriation from the General Assembly of $10,000 per annum for two years. In other words, this huge task was begun with an annual appropriation of one cent for each thirty- six acres. The growth of the work has since been so rapid and its value so evident that there is now an appropriation of one cent an- nually for about every four acres. The purpose of these investigations has been five-fold, for the in- telligent use of Illinois soils requires definite knowledge in regard to : (1) the plant-food requirements of the crops to be produced; (2) the total stock of plant food contained in the soil ; (3) the availability of the plant-food elements by practical methods of farming; (4) the most practical economical methods of supplementing or increasing the plant food in the soil; and (5) the systems of farming that will most profitably and permanently maintain the productive capacity of the soil. Such knowledge has been rendered possible by means of sys- tematic soil survey, chemical analysis, and culture experiments. SOIL SURVEY The soil survey has furnished much valuable information : first, by establishing by a general survey the existence of extensive soil types in the great soil areas into which the state is naturally divided ; and 451 452 BULLETIN No. 193 [December, second, by determining by detailed county survey the soil types upon every farm in the state. This detail survey when completed and mapped will give every farmer and landowner definite information concerning the soils upon his own farm, even down to ten-acre units or less. A map showing accurately the location and extent of the different soil types, with their principal variations and limits, is essentially the objective of the soil survey. During the fifteen years the work has been in progress, a general survey of the state has been made and more than sixty counties have been completely, or almost completely, sur- veyed in detail, in such order that every unsurveyed county borders two or more surveyed counties. At the present rate of progress the detail survey of the state should be completed in six or seven years. CHEMICAL ANALYSIS Chemical analysis of the soil has furnished an accurate invoice of the total amounts of the different essential elements of fertility contained in the soil to a depth to which plant roots normally extend. For obvious reasons this soil depth is divided into three strata : the surface, the subsurface, and the subsoil. The surface soil extends to the depth of good plowing (0 to 6% inches) and is that part with which the farm manure, limestone, phosphate, or other fertilizer is incorporated, and that part which must be depended upon largely to furnish the necessary plant food for the production of crops. The subsurface soil lies between the depths of 6% and 20 inches, and may be stirred by subsoiling. The subsoil extends from 20 to 40 inches. After a county has been surveyed, representative samples of every soil type established by the survey are secured from each of the three strata. Great care is used in every case to avoid the taking of samples that would not in every way be true to the soil type. Old stack yards and feed lots and fields that have been heavily manured or fertilized are avoided, and all other abnormalities are guarded against. When a suitable area has been selected, many soil samples are drawn at dif- ferent places some rods apart. The samples of each stratum are thoroly mixed and about ten pounds of the mixed soil is then bagged and given an official number. An exact record is also kept of the location from which the samples have been taken. Extensive types are sam- pled many times in the county ; less extensive types are sampled as they occur. The soil samples thus secured are sent to the Station laboratories, where they are prepared for analysis by thoro air-drying and pulver- izing. The pulverizing consists, first, in reducing the entire sample to such condition that it will pass thru a millimeter sieve (25 holes to the linear inch), a record being kept of the amount of pebbles, rock, and other material that will not pass thru ; and for certain determina- 1916\ SUMMARY OF ILLINOIS SOIL INVESTIGATIONS 453 tions it consists further in reducing about 100 grams of this soil to such fineness that it will all pass thru a sieve having 10,000 holes to the square inch. In all, nine different determinations are then made, as follows: for dry matter, for total organic carbon, total nitrogen, total phosphorus, total potassium, total calcium, total magnesium, total inorganic carbon for the presence of limestone, and for soil acidity, these being the most important plant-food elements and soil characteristics which are more or less under the control of the farmer. After the soil is analyzed, the reserve is stored away in vaults for any possible future use, such, for example, as determining the degree of solubility in various solvents, in case conditions should ever justify such work. PHOSPHORUS 1,200 MG. "^^ SCALE I MG,= I LB. FIG. 1. — PROPORTIONATE AMOUNTS OP POTASSIUM AND PHOSPHORUS IN THE SURFACE SOIL OF AN ACRE OF TYPICAL CORN-BELT SOIL All results of the chemical analyses are reported on the acre basis, assuming the weight of the surface soil to be 2 million pounds ; the subsurface, 4 million pounds ; and the subsoil, 6 million pounds. In the case of sand soils, however, 2i/2 million, 5 million, and iy2 million pounds, respectively, are used as the bases, and for peat soils, 1 million, 2 million, and 3 million pounds, on account of the difference in the specific gravities of these types. The results are so reported because they are easily understood and readily compared in practical applica- tion, and they are also scientifically exact. 454 BULLETIN No. 193 [December, Since the beginning of the work about 7,000 samples of soil have been collected from various parts of the state, and of this number approximately 4,600 have been analyzed. At the present rate of col- lecting and analyzing the samples (about five counties a year), twelve to thirteen years will be required to complete the work for the entire state. EXPERIMENT FIELDS Culture experiments have been conducted by the University upon experiment fields established in all sections of the state upon im- portant and representative soil types. The fields are so operated as to give the farmer positive information upon practical, economical, and permanent systems of soil management. Such experiments have been conducted on fifty fields in various parts of the state, thirty-nine of which are in operation at the present time. The first fields were established in the summer and fall of 1901 upon rented tracts of land. More or less difficulty prevailed at that time in securing suitable tracts because in many cases the farmers had little interest or confidence in the work; but this indifference gradu- ally changed to real interest, and at the end of six years the University was operating twenty fields. By 1908 the value of such fields for purposes of investigation and demonstration of soil improvement methods began to impress many people. Suitable tracts of land for such experiments were then offered and donated permanently to the University by local communi- ties and individuals, and from thenceforth the University has estab- lished no field except upon permanently deeded land. In recent years many more such tracts have been offered than could be accepted. In establishing a permanent field, it is the policy of the Univer- sity to choose a location where the results will, in every respect, be of the greatest value to the community. The land above all must be uniform in order that practical and trustworthy information may be secured. It must represent an extensive soil type so that the results secured from different systems of farming will be widely applicable to the conditions of the community. It should be upon a main thoro- fare and within easy walking distance from railroad stations so that it will be easily accessible to visitors. As new and permanent fields have been established, a number of the older temporarily rented fields in the same general locality have been given up, sometimes because the lease expired and could not be renewed. Fields that have been discontinued were located near the following places : Myrtle, Ogle county ; Tampico, Whiteside county ; Green Valley, Tazewell county; Lincoln, Logan county; Manito (old field), Mason county; Sibley, Ford county; Auburn, Sangamon county; Manito (new field). Tazewell county; Mascoutah, St. Hair j.9.76] SUMMARY OF ILLINOIS SOIL INVESTIGATIONS 455 county; Vienna (fertility field), Johnson county; and Momence, Kan- kakee county. At the present time twelve rented fields are still being operated, six of them temporarily and six with perpetual leases. Some of the former will undoubtedly have to be discontinued sooner or later on account of the impossibility of securing permanent possession of the land. These temporary fields are located near the following places : Antioch, Lake county; DeKalb, DeKalb county; Fairfield, Wayne county; Galesburg, Knox county; McNabb, Putnam county; and Rockford, Winnebago county. The six fields which may be perma- nently retained by the University are located near Odin, Marion county; Cutler, Perry county; Bloomington, McLean county; Du- Bois, Washington county ; Union Grove, Whiteside county ; and Vir- ginia, Cass county. In addition to the six permanently leased fields, the University has secured possession of twenty-seven fields so long as they are used for agricultural experimentation or demonstration. The perma- nent fields now owned by the University or controlled without rental expense are located as follows : (1) Aledo experiment field, Mercer county, about one-half mile west of the railway station at Aledo. The land was purchased and donated by the business men and landowners of Aledo and vicinity, in part thru the efforts of William and Vashti College. (2) Carlinville experiment field, Macoupin county, part of an eighty-acre tract 011 which Blackburn College is located. The perma- nent possession and use of this land was a direct donation from Black- burn College. (3) Carthage experiment field, Hancock county, within the cor- porate limits of Carthage, about five blocks south of the courthouse. The land was purchased and donated by the business men and land- owners of Carthage and vicinity, partially on account of their interest in Carthage College. (4) Clayton experiment field, Adams county, adjoining the town of Clayton. The field is about five blocks south of the railway station, and reached by a concrete walk. The land was donated by the citizens of Clayton and vicinity. (5) Dixon experiment field, Lee county, on the north side of the interurbaii railroad about two miles \vest of Dixon. The land was purchased and donated by the citizens of Dixon and vicinity. (6) Enfield experiment field, White county, three-quarters of a mile northeast of the town of Enfield. The land was purchased and donated by about six hundred citizens of White county. (7) Ewing experiment field, Franklin county, about one-half mile northeast of the village of Ewing. The land was purchased and donated by Ewing College with the assistance of friends of that institution. 456 BULLETIN No. 193 1916] SUMMARY OF ILLINOIS SOIL INVESTIGATIONS 457 (8) Hartsburg experiment field, Logan county, about one-half mile east of the village of Hartsburg. This land was donated by the Scully estate. (9) Joliet experiment field, Will county, three miles northwest of Joliet, on the Joliet-Plainfield wagon road and the Aurora-Joliet interurban line. The land was purchased and donated by Will county. (10) Kewanee experiment field, Henry county, about midway between Kewanee and Galva on the Galva and Kewanee electric line. The car stops at Midland about one-half mile south of the field. The land was purchased and donated by the citizens of Kewanee, Galva, and vicinity. (11) LaMoille experiment field, Bureau county, about one mile south of the corporate limits of LaMoille. The land was donated by Mrs. Anna Norris Kendall, and was a part of the farm on which her own residence, "Elizabeth Cottage," is located. (12) Lebanon experiment field, St. Clair county, about five blocks south of the main street of Lebanon. The land was purchased and donated by McKendree College, the purchase price being con- tributed for the purpose by Governor Charles S. Deneen, an alumnus and trustee of McKendree and at the time an ex-officio trustee of the University of Illinois. (13) Minonk experiment field, Woodford county, one mile west of Minonk. This land was donated by Mr. and Mrs. Bela M. Stoddard, of Minonk. (14) Mount Morris experiment field, Ogle county, immediately adjoining the residence district on the south side of Mount Morris. The land was purchased and donated by Mount Morris College and citizens of Mount Morris and vicinity. (15) Newton experiment field, Jasper county, about one and one-half miles northwest of Newton. The land was purchased and donated by Jasper county and the citizens of Newton and vicinity. (16) Oblong experiment field, Crawford county, five blocks south of the station at Oblong. The land was purchased and donated by the citizens of Oblong and vicinity. (17) Oquawka experiment field, Henderson county, about one mile northeast of the C. B. & Q. station at Oquawka. The field was donated by Mr. Alex Moir and others. (18) Pana experiment field, Christian county, just north and east of Pana, one mile from the Big Four and Illinois Central passen- ger station. This field was donated by the late Captain Kitchell, of Pana. (19) Raleigh experiment field, Saline county, one-half mile south of Raleigh, on land purchased and donated by citizens of Ra- leigh, Galatia, and vicinity. 458 BULLETIN No. 193 [December, (20) Sidell experiment field, Vermilion county, one mile directly east of Sidell. The land was purchased and donated by the citizens of Sidell and vicinity. (21) Sparta experiment field, Randolph county, immediately north of the city of Sparta. The land was purchased and donated by the citizens of Sparta and vicinity. (22) Spring Valley experiment field, Bureau county, about one- half mile from the business part of Spring Valley. The land was do- nated by the vocational township high school of Spring Valley. (23) Toledo experiment field, Cumberland county, about one- half mile south of the courthouse at Toledo. The land was purchased and donated by the county. (24) Urbana experiment field, Champaign county, on the Uni- versity farm. Part of this field has been under continuous experiment for thirty-seven years. So far as is known, it is the oldest experiment field in the United States on which the originally planned experiments are still in progress. It is unquestionably the most valuable land within the borders of the state, considering the annual lesson it now presents to the agricultural world. (25) Brookport-Unionville experiment field, Massac county, ad- joining the village of Unionville, five miles east of Brookport, on land purchased and donated by citizens of Massac county and southern Pope county. This experiment field is located on the most southern table land of the state, within five miles of the mouth of the Tennessee river, which flows "northward from Alabama and is said to modify appreciably the temperature of the Ohio river below Paducah and Brookport. (26) Vienna experiment field, Johnson county, about one mile south of Vienna.1 This field is rolling hill land and is devoted to a special study of surface washing and methods for its prevention. On part of the field destructive erosion is permitted to continue, as an object lesson. The land cost $20 an acre. (27) "West Sal em. experiment field, Edwards county, three-quar- ters of a mile southwest of the station at "West Salem. The land was purchased and donated by the citizens of "West Salem and vicinity. Thirty-six of the thirty-nine fields listed here are operated pri- marily to give Illinois farmers the most complete information possible upon systems of farming that will permanently maintain or increase the productive capacity of their soils. Of the three remaining, the fields near DeKalb in DeKalb county, and near Fairfield in Wayne county are given over mainly to crop investigations, and the Vienna field, as has been stated, is devoted to the study of methods of preventing soil washing and erosion. The distribution of those experiments fields is shown by Fig. 2. 'This tract is in addition to the leased land mentioned in the list of discon- tinued fields, page 454. 1916] SUMMARY OF ILLINOIS SOIL INVESTIGATIONS 459 PLAN AND METHODS OF FIELD INVESTIGATIONS Each experiment field contains on the average about twenty acres of land, divided into series which correspond to the different fields upon a farm. Each series is further divided into smaller areas, usually ten fifth-acre plots, and these are treated in such a manner that positive information can be secured in regard to the needs of the soil. Untreated plots are retained as checks in order to determine the effect of every kind of soil treatment applied. Crops are grown upon these fields in a definite rotation. On some fields two or more rotations are being tried. There are usually a sufficient number of series so that the crops of the main rotation are represented every year. The crops grown are those common to the locality and include wheat, corn, oats, barley, red clover, alsike, sweet clover, alfalfa, cowpeas, soybeans, vetch, timothy, and potatoes. Altho there may be a number of ways of meeting the needs of the soil with respect to better production, the Illinois Agricultural Ex- periment Station makes use largely of natural methods and natural materials. Instead of applying expensive complete fertilizers, which may produce a more or less rapid response, wide use is made of such natural materials as farm manure, legume crops, crop residues, ground limestone (both ordinary and dolomitic, each of which is found in abundance in Illinois), steamed bone meal (a farm product), and ground natural raw rock phosphate. Abundant information points to the fact that in the long run and under normal conditions the use of these materials in well planned systems of farming usually proves to be the most practical and economical method of soil improvement. In some comparative experiments and on some abnormal soils, purchased nitrogen, manufactured acid phosphate, potassium salts, and other commercial fertilizers are used. In order that the reader may better understand the operation of a typical experiment field, the arrangement and methods used on the field located at Urbana are here described. The accompanying dia- gram of the field shows the manner in which the series and individual plots are arranged. The treatment given each plot and the method of numbering is indicated thereon. Each plot covers exactly one- tenth of an acre. A combination rotation is practiced which is well suited to the farming conditions of this region of the state. Corn, oats, clover, and wheat, in the order named, rotate once completely over four fields while a fifth field is in alfalfa. After the four crops have been rotated over the four fields for five years, the alfalfa is changed to one of the other fields, and the old alfalfa field is then used in the four-year rotation. This is repeated until the alfalfa again occupies the same field. The whole rotation will cover a period of twenty-five years. 460 BULLETIN No. 193 [December, So/ foi Soy « 4 J^oj- J~o< fe^ S~ot 5-0 f j-/o O ft M R M R M K M c^ 1- L. t. u \_ IW*" P P P P L K 4.01 o + 02 R 4-03 M 4-04 R M 4- H IP CO 'o H 3 ^ "3 o OQ .2 'C ^ ° -P tnj (- '3 « 2 'a o ^ PH § 3 ^ a .2 r2 ^ a 3 -2 2 "E, P '3 cS 3 1 'So M ,-g h O 3 .S ^ H h « (X > l\* <1 _ "S CO ( ^J . .-H p . O jO -*j 'mOO 2; rH rH • H (M O ooeof-io i— i os --^ (MOit^CC COO5.i-HTti^ COO5COO5 i— 1 OO (M O t- (MCOCOCOCO IOOOOO oqinoowec ^S 1— 1 r* C §. R R B IB o in o o o •* rH OS >O t~ O IM •* IO »O LO O O O «O CO O •* rt* OJ CO OS rH O cS g " m LIBRARY OF THE UNIVERSITY OF ILLINOIS II II o a Eg cl II og £8 ^•^^ ^l^~ I M fl. c • E 2 B 0 c o 1 JD 01 .2 •o T3 «J a S of bO te E 2 O. £ c 0 c o o I £ 1 I « >* o> T3 « 3 -o 0 1 B000 i — i 0101 1916] SUMMARY OF ILLINOIS SOIL INVESTIGATIONS 467 the surface about enough nitrogen for 48 crops and sufficient phos- phorus for 70 crops. On the other hand, it contains enough potassium to produce 1,790 such crops; and with good methods of farming, potassium may be renewed rapidly enough from the subsoil, by un- avoidable surface washing, to maintain the potassium content of the soil indefinitely. If production is to be maintained, it will be neces- sary, therefore, to supplement the supply of nitrogen and phosphorus in these soils. The necessity for the use of organic matter is indicated by the ratio of nitrogen to organic carbon. A narrow ratio exists where the organic-matter content is low, and a wide one where there is sufficient of this material present. Measured by actual crop requirements, some of these soils show a deficiency in the elements calcium and magnesium. Limestone, therefore, in addition to correcting soil acidity, may have considerable value for the calcium and magnesium which it contains. While the amount of plant food contained in the subsurface and subsoil strata is of interest, no analyses for these strata are reported here. The chief thing of importance in systems of permanent, profit- able agriculture is the maintenance of a good surface soil, for even a rich subsoil is of but little value if it lies beneath a worn-out surface. For detailed discussion of the fertility in Illinois soils below the seven- inch depth, the reader is referred to the various soil reports issued by this station and to Bulletin 123. RESULTS OF FIELD-CULTURE EXPERIMENTS The field-culture experiments planned in connection with the in- formation furnished by the soil survey and soil analysis have demon- strated that it is possible to practice a system of farming that is both permanent and profitable. A summary of the results secured upon a number of the most important soil types in the different soil areas, showing the effect and value of various forms of soil treatment, is presented upon the following pages. The data are arranged by soil types, which are presented according to age when occurring in more than one soil area. Since a definite system of farming may or may not be profitable, depending upon the price received for produce, the field results are usually summarized in two sets of money values to emphasize this fact. Low prices are used to represent the value of the produce in the field, and high prices to represent the market value. The prices used are as follows : corn, 35 and 50 cents per bushel ; oats, 28 and 40 cents ; wheat 70 cents and $1 ; soybeans, 70 cents and $1 per bushel. Meas- ured by average Illinois prices for the past ten years, the lower values are not too high for crops standing in the field ready for harvest. Un- less otherwise specified, these are the values used in the following discussion. 468 BULLETIN No. 193 [December, UPLAND PRAIRIE SOILS Black Clay Loam of Early Wisconsin Glaciation (1120) Urbana Field. — At Urbana, on the South Farm of the University of Illinois, a series of plots devoted primarily to crop-production ex- periments extends across an area of black clay loam. A four-year rotation of wheat, corn, oats, and clover (or soybeans) is practiced. Where rock phosphate has been applied at the rate of 500 pounds an acre per annum in connection with crop residues in the grain system, the value of the increase per ton of phosphate has been as follows, in three successive rotations: Lower prices Higher prices First rotation $2.13 $3.04 Second rotation 4.70 6.71 Third rotation 6.48 9.26 In the live-stock system, the phosphorus naturally supplied with the manure, supplemented by that liberated from this fertile soil, has been approximately sufficient to meet the crop requirements. The value of the increase per ton of phosphate, as an average of the twelve years, has been only $2.26 at the lower prices and $3.26 at the higher prices. These returns are less than half the cost of the phosphorus applied, and in some seasons no benefit has appeared. Brown Silt Loam of Middle Illinoisan Glaciation (426) Virginia Field. — At Virginia, in Cass county, the University es- tablished an experiment field in 1902 upon brown silt loam somewhat above the average in productive power. A three-year rotation was begun on three different series of plots. Corn, oats, and cowpeas were grown the first six years, after which the rotation was changed to corn, oats, and clover. During the first seven years (1902 to 1908), phosphorus applied at the rate of 25 pounds per acre per annum in the form of steamed bone meal produced an increase of 6.8 bushels of corn, .4 bushel of oats, .04 ton of hay. During the next three years (1909 to 1911), the increases were 10.5 bushels of corn, 13.1 bushels of oats, and .69 ton of hay. These results were to be expected, for the chemical analysis of the soil shows that phosphorus is not abundant and that nitrogen is the first limiting element. Thus phosphorus could show no marked effect until nitrogen was gradually increased by the use of legume crops and farm manure. On another series, commercial nitrogen was applied in a four- year rotation of corn, corn, oats, and wheat, thus giving an opportunity to compare this form of nitrogen to that supplied the soil by grain and live-stock farming. On plots treated alike with respect to lime and phosphorus, legumes in rotation and some crop residues plowed 1916] SUMMARY OF ILLINOIS SOIL INVESTIGATIONS 469 under increased the six-year average yield of corn by 24.2 bushels, and farm manure and legumes increased the yield by 26.6 bushels; while 100 pounds of commercial nitrogen in about 800 pounds of dried blood, costing $15 to $20 per annum, increased the yield only 19.5 bushels. The two important lessons from the Virginia field are : first, when nitrogen is the limiting element, nothing else can take its place, and, even tho phosphorus may be deficient, its addition will not produce marked results until sufficient nitrogen is provided ; second, the grow- ing of legumes in rotation and the use of crop residues or farm manure may produce even better results than high-priced commercial nitrogen. (For further details see Soil Eeport No. 4, Sangamon county.) Brown SUt Loam of Upper Illinoisan Glaciation (526) Galesburg Field. — Upon the experiment field located near Gales- burg on brown silt loam prairie soil, a six-year rotation of corn, corn, oats, clover, wheat, and clover has been practiced. There are only three independent series of plots, so that while corn is grown every year, the other crops are harvested every other year, with the excep- tion of clover, which should be on the field every year either as a regular crop or in the stubble of oats and wheat. The twenty plots of each series are so treated that the value of additions, consisting of phosphorus in the form of rock phosphate, potassium, and limestone, may be known in both live-stock and grain farming (see page 461). On Plot 19 of the three series, commercial, nitrogen at the rate of 25 pounds an acre per annum is used in addi- tion to the regular treatment. Three facts are clearly brought cut by the data from this field : First. — Commercial nitrogen at 15 cents a pound has never paid its cost. As the system of providing "home-grown" nitrogen has developed, the effect of commercial nitrogen has decreased, and as an average of the five years 1908-1912 it paid back only 4 percent of its annual cost. Second. — Potassium, likewise, has never paid its cost ; but during the early years, with no adequate provision for decaying organic matter, the soluble potassium salts produced marked effect, owing no doubt in part to their power to make available the raw phosphate rock applied with the potassium. With the increase of organic matter, the effect of the potassium has been greatly reduced. As an average of the six years from 1907 to 1912, potassium costing $7.50 paid back only $1. Third. — Fine-ground rock phosphate applied at the rate of 500 pounds an acre per annum in connection with decaying organic matter has paid back the following increases in crop values per ton of phos- phate applied: 470 BULLETIN fto. 193 [December, Lower prices Higher prices Average 1904 and 1905 $3.53 $5.04 Average 1906-1908 7.73 11.04 Average 1909-1911 8.60 12.29 Average 1912-1914 12.93 18.49 These increases have been realized by the removal from the soil of only one-third of the phosphorus applied, leaving two-thirds in the soil as positive enrichment. (See Soil Report No. 6, Knox county, for detailed data on crop yields, etc.) Brown Silt Loam of Early Wisconsin Glaciation (1126) Sibley Field. — The Sibley experiment field, located in Ford county upon typical brown silt loam prairie soil, was cropped previous to 1902 with corn and oats under a tenant system which had caused the active organic-matter content to be somewhat deficient. One series of plots treated in such a manner as to bring out facts concerning the needs of the soil, in which phosphorus is the limiting element, has furnished some interesting information. In 1903 the addition of phosphorus produced an increase of 8 bushels of corn, nitrogen produced no increase, but nitrogen and phos- phorus combined increased the yield by 15 bushels. After six years of additional cropping, nitrogen appeared to become the most limiting element, the increase in corn in 1907 being 9 bushels from nitrogen and only 5 bushels from phosphorus, while nitrogen and phosphorus together produced an increase of 33 bushels. Thus even tho phos- phorus was a limiting element, the nitrogen becoming available an- TABLE 2. — VALUE OF CROPS PER ACRE IN TWELVE YEARS, SIBLEY FIELD 1902 TO 1913 Plot Soil treatment applied Total value of 12 crops Lower prices Higher prices 101 102 None . . . . $172.89 186.51 $246.98 266.45 Lime 103 104 105 Lime nitrogen . .... 177.44 217.78 167.32 253.49 311.11 239.03 Lime phosphorus Lime, potassium 106 107 108 Lime nitrogen phosphorus 246.91 198.16 204.90 352,73 283.08 292.71 Lime nitro°°en potassium Lime, phosphorus, potassium 109 110 257.91 242.47 368.45 346.38 Nitrogen, phosphorus, potassium Value of Increase per Acre in Twelve Years For nitrogen For phosphorus '. For nitrogen and phosphorus over phosphorus For phosphorus and nitrogen over nitrogen For potassium, nitrogen, and phosphorus over nitrogen and phosphorus $-9.07 31.27 29.13 69.47 11.00 $-12.96 44.66 41.62 99.24 1916] SUMMARY OF ILLINOIS SOIL INVESTIGATIONS 471 nually was but little in excess of the phosphorus. The untreated land apparently became less productive, whereas on land receiving both nitrogen and phosphorus the yields were appreciably increased, so that in 1907 the untreated rotated land produced only 34 bushels of corn and the land treated with lime, nitrogen, and phosphorus yielded 72 bushels per acre (more than twice as much), altho both plots pro- duced the same yield (57.3 bushels) in 1902. The total values per acre of the twelve crops for each plot are shown in Table 2. Here it is seen that with the lower prices phosphorus without nitrogen produced $31.27 in addition to the increase by lime, but that with nitrogen it produced $69.47 above the crop values where only lime and nitrogen have been used. The results show that in 26 cases out of 48 the addition of potassium decreased crop yields. Lime pro- duced an average increase of $14.53, or $1.21 an acre per year; which shows that the time has come when limestone must be applied to some of the brown silt loam soils. (Detailed data in regard to crop yields will be found in Soil Report No. 10, McLean county.) Bloomington Field. — The results of thirteen years' work on the experiment field located near Bloomington on brown silt loam prairie soil are much the same as those from the Sibley field, as may be seen from Table 3. The treatment of this field differs from that at Sibley in that in 1905 the use of commercial nitrogen was discontinued, clover wras introduced into the rotation, and crop residues Avere subsequently re- turned to the soil. "With this method, phosphorus has produced even TABLE 3. — VALUE OP CROPS PER ACRE IN THIRTEEN YEARS, BLOOMINGTON FIELD 1902 TO 1914 Plot Soil treatment applied Total value of 13 crops Lower prices Higher prices 101 102 None $186.83 186.76 $260.90 266.80 Lime 103 104 105 Lime, residues 193.83 286.61 190.53 276.90 409.45 272.19 Lime, phosphorus Lime, potassium 106 107 108 Lime, residues, phosphorus 285.03 191.10 294.91 407.19 273.00 421.31 Lime, residues, potassium Lime, phosphorus, potassium 109 110 Lime, residues, phosphorus potassium 284.47 259.10 406.39 370.15 Residues, phosphorus, potassium. . Value of Increase per Acre in Thirteen Years For residues For phosphorus For residues and phosphorus over phosphorus For phosphorus and residues over residues For potassium, residues, and phosphorus over residues and phosphorus $ 7.07 99.85 -1.58 91.20 $ 10.10 142.65 -2.26 130.29 -.80 472 BULLETIN No. 193 [December, larger increases ($99.85) than have been produced by phosphorus and nitrogen over nitrogen on the Sibley field ($69.47). The average yearly increase due to phosphorus in connection with the use of legume TABLE 4. — YIELDS PER ACRE, THREE- YEAR AVERAGES, URBANA FIELD First Eotation: 1902-1904 Serial plot No. Soil treatment Corn bu. Oats bu. Hay tons Value of 3 crops Lower prices Higher prices 1 2 3 4 5 None 75.4 77.4 75.3 78.4 80.8 48.8 45.1 50.4 47.3 58.2 .49 .44 .41 .42 .44 $43.48 42.80 43.33 43.62 47.66 $62.12 61.14 61.91 62.32 68.08 Legume cover crop None Legume cover crop, lime Lime 6 7 8 9 10 Legume cover crop, lime, phosphorus 88.0 88.8 90.1 90.5 86.5 52.5 56.6 48.3 54.3 53.2 .50 .98 .64 1.34 1.23 49.00 53.79 49.53 56.26 53.78 70.00 76.84 70.77 80.37 76.83 Lime, phosphorus Legume cover crop, lime, phosphorus, potassium Lime, phosphorus, potassium Lime, ohosohorus. t»otassium . . Second Eotation: 1905-1907 Serial plot No. Soil treatment Corn bu. Oats 1>u. Clover tons Value of 3 crops Lower prices Higher prices 1 2 3 4 5 None 71.5 68.5 80.5 72.3 84.8 46.6 52.0 54.8 58.6 59.8 2.07 1.83 2.19- 1.98 2.46 $52.56 51.34 58.84 55.57 63.64 $75.09 73.35 84.07- 79.39 90.92 Legume cover crop Manure Legume cover crop lime Manure, lime 6 7 8 9 10 Legume cover crop, lime, phosphorus 90.4 93.2 93.8 95.6 901 70.7 71.6 71.7 66.9 6!? 9 2.69 3.47 3.06 3.73 2.86 70.26 76.96 74.32 78.30 69.17 100.38 109.94 106.18 111.86 98.81 Manure, lime, phosphorus Legume cover crop, lime, phosphorus, potassium Manure, lime, phosphorus, potassium .... Manure (*}. lime. DnosDhorus ( x^ . . Third Rotation: 1908-1910 Serial plot No. Soil treatment Corn bu. Oats bu. Clover tons (bu.) Value of 3 crops Lower prices Higher prices 1 2 3 4 5 None 49.4 51.5 69.3 58.1 74.9 40.8 43.4 46.2 45.7 47.5 2.30 (1.93) 2.53 (2.02) 2.94 $44.81 43.69 54.90 47.27 60.09 $64.02 62.41 78.43 67.53 85.85 Residues . Manure Residues, lime Manure, lime 6 7 8 9 10 Residues lime phosphorus 83.8 86.6 86.7 90.9 81.3 54.5 55.4 53.5 53.6 54.3 (2.64) 4.17 (1.99) 3.90 3.79 63.07 75.01 59.26 74.12 70.19 90.10 107.16 84.65 105.89 100.27 Manure, lime, phosphorus Residues, lime, phosphorus, potassium . . . Manure, lime, phosphorus, potassium .... Manure (x), lime, phosphorus (x) X— extra heavy applications of manure and phosphorus; residties=:corn stalks, straw of wheat and oats, and all legumes except seed. 1916] SUMMARY OF ILLINOIS SOIL INVESTIGATIONS 473 TABLE 5.— YIELDS PER ACRE, FOUR-YEAR AVERAGES, URBANA FIELD 1911 TO 1914 Serial plot No. Son treat- ment Wheat In. Corn Zm. Oats 2m. Soybeans-3 tons (bu.~) Clover-1 tons (6«.) Alfalfa tons Value o Lower prices £ 5 crops Higher prices 1 2 3 4 5 0 18.3 19.7 20.3 22.3 24.9 50.8 53.8 59.3 55.7 58.6 39.8 40.6 48.8 42.8 51.6 1.60 (20.1) 1.60 (19.0) 1.66 1.70 ( .74) 1.43 (1.03) 1.94 1.70 1.27 1.13 1.19 1.67 $65.00 64.72 : 67.44 67.20 76.19 $92.87 92.47 96.35 96.00 108.84 R M RL. . . . ML 6 7 8 9 10 RLP... MLP... RLPK. MLPK. MxLP*. 37.4 36.6 36.1 35.3 43.5 62.2 63.8 58.9 59.6 55.7 58.7 60.9 59.1 65.1 67.2 (21.0) 1.88 (22.2) 2.09 2.14 (2.48) 2.90 (1.41) 2.72 2.94 2.69 2.63 2.58 2.66 2.84 98.58 98.36 94,61 98.15 105.02 140.83 140.51 135.16 140.22 150.03 Lezulegume cover crop; L=lime; Pz=phosphorus ; M=manure; x— extra heavy applications of manure and phosphorus; R=crop residues (corn stalks, straw of wheat and oats, and all legumes except seed and alfalfa hay). crops or nitrogen has been $7.02 an acre, which is $4.52 above the cost of phosphorus in 200 pounds of steamed bone meal, the form in which it is applied. The total phosphorus applied from 1902 to 1914, as an average of all plots where it has been used, has amounted to 325 pounds per acre and has cost $32.50. This has paid back $97.20, or 300 percent on the investment. Potassium, on the other hand, has paid back less than 7 percent of its cost in the thirteen years. (De- tailed data in regard to crop yields will be found in Soil Report No. 10, McLean county.) Urbana Field. — On the University North Farm at Urbana, on the' common brown silt loam prairie soil, a rotation of corn, oats, and clover was practiced for nine years (1902 to 1910), which has been followed by a combination rotation involving corn, oats, clover, wheat, and alfalfa. The various plots upon each series are so treated as to show the value of various additions in both live-stock and grain farm- ing. On all series, Plot 10 is treated with about five times as much manure and phosphorus as is applied on the other plots, in order to remove the limitations of inadequate fertility and thus to determine the climatic possibilities of crop yields. Tables 4 and 5 give the three- year and the four-year averages, respectively, of crop yields and the value of the crops by rotations, with both the higher and the lower prices. No detailed discussion of this interesting data will be given here (see Soil Report No. 9, Lake county, or No. 10, McLean county), but a few points of interest will be indicated for further study. While seasonal variations are inevitable, a comparison of crop yields by rotations, with and without soil treatment, is instructive. On the untreated land distinctly higher average yields of corn appear in the first rotation than in succeeding rotations, as 75.4 bushels in the first and 49.4 bushels in the last of the three-year rotations. The 474 BULLETIN No. 193 difference in yields of corn between treated and untreated land be- comes greater with succeeding rotations, as is seen by the difference of 13.4 bushels between Plots 1 and 7 in the first rotation, and of 37.2 bushels between the same plots in the last of the three-year rotations. Such evidence points to the fact that fertility cannot be maintained by rotation alone, but that with a good system of soil treatment maxi- mum production may be expected indefinitely. Attention is also called to the striking effects of soil treatment upon the wheat yields, which show 100 percent increase, as an average, during the four-year rotation. At the lower prices for produce, farm manure has been worth 84 cents per ton during the ten years it has been used on Plot 3. As a general average, the plots receiving limestone have produced $1.22 an acre a year more than the plots not receiving limestone, and this corresponds to more than $6 a ton for all the limestone applied ; FIG. 6. — METHOD OF SCATTERING LIMES PHOSPHORUS1 but the amounts of limestone applied before 1911 were so small and the results so variable that final conclusions cannot be drawn until further data are secured. However, since all comparisons of rotation periods show some increase, the need of limestone for the best results and the highest profits seems well established. Potassium applied at an estimated cost of $2.50 an acre a year seemed to produce slight increases, on the average, during the first and second rotations, but the net result thru the 1914 yields was an 'For description of this machine, see page 16 of Circular 110 of this station. 1916] SUMMARY OF ILLINOIS SOIL INVESTIGATIONS 475 average loss of $2.53 per acre per annum, including the cost of the potassium. The annual application of 25 pounds of phosphorus in 200 pounds of steamed bone meal valued at $28 per ton, or of 75 pounds in 600 pounds of rock phosphate valued at $7 per ton, in connection with decaying organic manures, has, as an average for each dollar invested in phosphorus, paid as follows : Lower prices Higher prices First rotation, 1902-1904 $ ,69 $ .99 Second rotation, 1905-1907 1.67 2.39 Third rotation, 1908-1910 2.09 2.99 Fourth rotation, 1911-1914 2.19 3.13 The excessive applications on Plot 10 have usually produced rank growth of straw and stalk, with the result that oats have often lodged badly and corn has frequently suffered from drouth and has eared poorly. Wheat, however, as an average, has yielded best on this plot. The largest yield of corn was 118 bushels per acre in 1907. On the University South Farm at Urbana, on typical brown silt loam prairie, where one ton per acre of rock phosphate is applied every four years in connection with organic manures for a rotation of corn, oats, clover, and wheat, applications of fine-ground rock phos- phate have paid as follows in the value of the increase produced : PER TON OF PHOSPHATE PER $1 INVESTED Lower Higher Lower Higher prices prices prices prices First rotation, 1903-1906 $8.26 $11.80 $1.18 $1.69 Second rotation, 1907-1910 11.33 16.19 1.62 2.31 Third rotation, 1911-1914 18.89 26.98 2.70 3.85 The comparative values of the increases from rock phosphate and limestone, as an average of the four-year rotation 1911-1914, in both live-stock and grain farming, are as follows: EESIDUE SYSTEM LIVE-STOCK SYSTEM Lower Higher Lower Higher prices prices prices prices Gain for phosphorus $18.80 $26.86 $18.96 $27.09 Gain for limestone 2.30 3.29 2.54 3.63 Brown-Gray Silt Loam on Tight Clay of Middle Illinoisan Glaciation (428) Mascoutan Field. — Table 6, showing the value of twelve crops from the Mascoutah experiment field located upon brown-gray silt loam on tight clay of the middle Illinoisan glaciation, are given here since there is no data for this type in either the lower or the upper Illinoisan glaciation. In order to secure information as quickly as possible, commercial plant foods in readily available form were ap- plied in a four-year rotation of corn, corn, oats, and wheat. 476 BULLETIN No. 193 [December, TABLE 6. — VALUE OF CROPS PER ACRE IN TWELVE YEARS, MASCOUTAH FIELD 1902 TO 1913 Plot Soil treatment applied Total value of 12 crops Lower prices Higher prices 501 502 None $90.07 90.47 $128.67 129.24 Lime 503 504 505 Lime, nitrogen 134.46 106.10 100.96 192.08 151.57 144.23 Lime, phosphorus Lime, potassium 506 507 508 Lime, nitrogen, phosphorus 190.55 205.60 123.84 272.21 293.72 176.92 Lime, nitrogen, potassium Lime, phosphorus, potassium 509 510 Lime, nitrogen, phosphorus, potassium 190.67 177.58 272.39 253.69 Nitrosren. phosphorus, potassium . Value of Increase per Acre in Twelve Years For nitrogen For phosphorus For nitrogen and phosphorus over phosphorus For phosphorus and nitrogen over nitrogen For potassium, nitrogen, and phosphorus over nitrogen and phosphorus $43.99 15.63 84.45 56.09 .12 $62.84 22.33 120.64 80.13 .18 Nitrogen is clearly the element of greatest benefit upon this soil type, as shown by the fact that in twelve years the dried blood in- creased the crop values, at the lower prices, from $90.47 to $134.46, a gain of $43.99. In comparison, phosphorus produced an increase valued at $15.63 and potassium an increase of only $10.49, when used singly. In considering these three elements, starting with $90.47 (Plot 2), the increases per acre in crop values were as follows: For nitrogen over lime $ 43.99 For phosphorus as a further addition 56.09 For potassium as a final addition .12 For total increase $100.20 This demonstration of doubling crop values is highly important, for it shows the possibilities of soil treatment. From the composition of the soil it is clear that both nitrogen and phosphorus must be sup- plied for a permanent system of farming, altho there may be some question as to which of the two is most needed. Commercial nitrogen, altho producing marked gains, never paid its cost; and while phos- phorus paid nearly 200 percent on the investment in steamed bone meal when used in addition to nitrogen, the profit is more than offset by the nitrogen deficit. On another part of Mascoutah field investigations we^e conducted to secure information in regard to the practicability of securing nitro- gen by the less expensive practice of growing legumes in the rotation and returning to the soil the crop residues and farm manure. A comparison of these results for eight years shows that the crop values 1916] SUMMARY OP ILLINOIS SOIL INVESTIGATIONS 477 TABLE 1- - VALUE OF CROPS PER ACRE IN FOURTEEN YEARS, DuBois FIELD 1902 TO 1915: NOT TILE-DRAINED Plot Soil treatment applied Total value of 14 crops Lower prices Higher prices 101 102 $63.83 88.28 $91.19 126.11 Lime 103 104 105 Lime) residues 113.66 145.66 144.97 162.37 208.09 207.10 Lime, phosphorus Lime, potassium 106 107 108 Lime, residues, phosphorus 165.07 172.34 186.02 235.82 246.20 265.75 Lime residues potassium Lime, phosphorus, potassium -. 109 110 Lime, residues, phosphorus, potassium 196.39 140.50 280.55 200.71 E«sidues. Dhosohorus. Dotassium. . Value of Increase per Acre in Fourteen Years For lime For residues For phosphorus For residues and phosphorus over phosphorus For phosphorus and residues over residues For potassium, residues, and phosphorus over residues and phosphorus $24.45 25.38 57.38 19.41 51.41 31.32 $34.92 36.26 81.98 27.73 73.45 44.73 at the lower prices averaged $119.38 where commercial nitrogen cost- ing $120 was used, and $119.61 and $117.20 where residues and farm manure, respectively, were used. These data show that practically the same gross values are secured with "home-grown" nitrogen as with the purchased product, and at much less cost. (Detailed data in regard to crop yields will be found in Soil Report 8, Bond county.) Gray Silt Loam on Tiglit Clay of Lower Illinoisan Glaciation (330) DuBois Field. — Data are presented in Tables 7 and 8 showing the results of soil experiments and tile drainage upon gray silt loam on tight clay, the common prairie soil of southern Illinois. A summary of these data shows that tile drainage has paid $6.37 per acre in fourteen years, or 45 cents per acre per year. It would require at least $1.20 per acre per year to pay 6 percent interest on the cost of the tile drainage, assumed to be $20 per acre. A summary of the average results from the tiled and the untiled land for the fourteen years shows a crop value of $63.40 per acre from the unfertilized land, and increases for additions as follows : For lime alone $30.39 or 48 percent For nitrogen and organic matter over lime. . . . 24.26 or 26 For phosphorus as a further addition 54.39 or 46 For potassium as a final addition 22.37 or 13 For total increase over untreated land $131.41 or 207 percent 478 BULLETIN No. 193 [December, TABLE 8. — VALUE OF CROPS PER ACRE IN FOURTEEN YEARS, DuBois FIELD 1902 TO 1915: TILE-DRAINED Plot Soil treatment applied Total value of 14 crops Lower prices Higher prices 111 112 None $62.98 99.32 $89.97 141.89 Lime 113 114 115 Lime, residues 122.47 136.54 146.48 174.96 195.06 209.26 Lime, phosphorus Lime, potassium . 116 117 118 Lime, residues, phosphorus 179.84 181.45 193.43 256.89 259.22 276.33 Lime, residues, potassium Lime, phosphorus, potassium 119 120 Lime, residues, phosphorus, potassium 193.26 164.70 276.08 235.29 Residues. phosphorus, potassium. . Value of Increase per Acre in Fourteen Years For lime For residues For phosphorus For residues and phosphorus over phosphorus For phosphorus and residues over residues For potassium, residues, and phosphorus over residues and phosphorus $36.34 23.15 37.22 43.30 57.37 13.42 $51.92 33.07 53.17 61.83 81.93 19.19 These results harmonize with those that would be expected from the chemical composition of the soil. It is likely that as the organic- matter content of the soil increases, the effect of the potassium will be diminished. Fairfield Field. — Upon the experiment field located near Fair- field, Wayne county, on typical gray silt loam on tight clay, a four- year rotation of corn, cowpeas or soybeans, wheat, and clover is prac- ticed upon four independent series of plots. Live-stock and grain farming, with the use of limestone and rock phosphate, are practiced upon tiled and untiled land. In Table 9 the results from the field as a whole for eight years are concisely summarized by rotations. (For more detailed information, see Soil Report No. 8, Bond county.) Here untreated well-rotated land produced $19.69 per acre in four- years at the lower values, while the land receiving farm manure, ground limestone, and fine-ground raw rock phosphate produced $53.04 in the second rotation. If it costs $5 an acre a year to farm the un- treated land, the returns lack 8 cents of paying the cost, leaving noth- ing for taxes and interest; moreover this land is becoming poorer each year. From the standpoint of tile drainage the value of the increase, at the lower prices, has been $1.08 per acre for each of the eight years. It would take at least $1.50 an acre a year to pay 6 percent interest on the cost of the tile drainage at $25 per acre. During the last four years of tile drainage, the increase was $1.79 per acre per 1916] SUMMARY OF ILLINOIS SOIL INVESTIGATIONS 479 TABLE 9. — CROP VALUES PER ACRE, FAIRFIELD FIELD 1905 TO 1912 First Kotation: Average of Four Series Soil treatment. . None Farm manure Limestone Phosphate Farm manure Limestone Phosphate Lower prices Higher prices Lower prices Higher prices Lower prices Higher prices Lower prices Higher prices Value of 4 crops $19.69 $28.14 $24.34 $34.76 $26.91 $38.44 $36.42 $52.03 Second Kotation: Average of Four Series Soil treatment . . Crop residues Farm manure Crop residues Limestone Phosphate Farm manure Limestone Phosphate Value of 4 crops Lower prices $20.25 Higher prices $28.92 Lower prices $25.45 Higher prices $36.36 Lower prices $38.14 Higher prices $54.49 Lower prices $53.04 Higher prices $75.79 year, which would pay a fair rate of interest providing the cost of the drainage did not exceed $30 per acre. Tile drainage may ultimately prove to be profitable. UPLAND TIMBER SOILS Yellow-Gray Silt Loam of Lower Illinoisan Glaciation (334) Raleigli Field. — Upon the experiment field located at Raleigh, Saline county, on typical yellow-gray silt loam, a four-year rotation of wheat, corn, oats and clover (or cowpeas or soybeans) is practiced. As an average of duplicate trials each year, the crop values for the years 1911-1914 from four acres were, at the lower prices, $16.44 from untreated land, $18.22 where organic manures were applied in pro- portion to the amount of crops produced, and $33.58 where 6 tons per acre of limestone and organic manure were applied. Owing to the low supply of organic matter, phosphorus produced almost no benefit. However, writh increasing applications of organic matter the effect of phosphorus is becoming more apparent. Yellow-Gray Silt Loam of Late Wisconsin Glaciation (1234) Antiocli Field. — The Antioch experiment field located upon yel- low-gray silt loam of the late Wisconsin glaciation was so planned that the effect of various additions might be known as quickly as possible. The elements nitrogen, phosphorus, and potassium were applied in commercial form until 1911, after which commercial nitrogen was discontinued and crop residues substituted. Altho the soil is somewhat irregular and some abnormal seasons 480 BULLETIN No. 193 [December, TABLE 10. — VALUE OF CROPS PEE ACRE IN THIRTEEN YEARS, ANTIOCH FIELD 1902 TO 1914 Plot Soil treatment applied Total value of 13 crops Lower prices Higher prices 101 102 None $135.12 119.74 $193.03 171.06 Lime 103 104 105 Lime, nitrogen 124.70 202.20 138.88 178.15 288.85 198.40 Lime, phosphorus Lime, potassium 106 107 108 Lime, nitrogen, phosphorus 179.41 133.54 201.35 256.31 190.77 287.65 Lime, nitrogen, potassium Lime, phosphorus, potassium 109 110 Lime, nitrogen, phosphorus, potassium 191.22 181.18 273.18 258.83 Nitroeren. phosphorus, potassium. . Value of Increase per Acre in Thirteen Years For nitrogen For phosphorus For nitrogen and phosphorus over phosphorus For phosphorus and nitrogen over nitrogen For potassi/um, nitrogen, and phosphorus over nitrogen and phosphorus $ 4.96 82.46 -22.79 54.71 11.81 $ 7.09 117.79 -32.54 78.16 16.87 have caused almost complete crop failures, the general summary strongly confirms the analytical data in showing the need of applying phosphorus, and the profit from its use, and the loss in adding potas- sium. In most cases commercial nitrogen damaged the small grains by causing the crop to lodge. From the results of other fields we must conclude that better yields are to be secured by providing nitrogen by means of farm manure and legume crops grown in rotation than by the use of commercial nitrogen, which is evidently too readily available, causing too rapid growth and consequent weakness of straw. Table 10 gives the summarized results for thirteen years. (For more detailed information see Soil Report No. 9, Lake county, or No. 10, McLean county.) Yellow Silt Loam of Unglaciated Areas (135) of Upper Illinoisan Glaciation (535) Pot-Culture Experiments. — Yellow silt loam soil collected from an unglaciated area and from the upper Illinoisan glaciation was ar- ranged in two series of ten four-gallon jars for greenhouse culture work and treated by additions in the same manner as for field-culture work. As an average, the nitrogen applied produced a yield about eight times as large as that secured without the addition of nitrogen. To determine whether "home-grown" nitrogen would be as efficient as 1516] SUMMARY OF ILLINOIS SOIL INVESTIGATIONS 481 commercial nitrogen, other pots were arranged, and to some commer- cial nitrogen was applied, and in others cowpeas were grown and turned under. The increase due to commercial nitrogen was not suffi- cient to cover the cost of the application. After the second crop of cowpeas had been turned under, the legume manures, as an average, made rather better results than the commercial nitrogen. These re- sults confirm the analytical data in showing the great need for nitro- gen ; and they further show that such nitrogen need not be purchased. Vienna Field. — Since yellow silt loam is subject to erosion and washing, the control of these factors is exceedingly important. The experiments carried on at Vienna, Johnson county, upon an unglaci- ated area of this type of soil are conducted solely in the interest of these problems. The management of this field includes deep plowing, contour plowing, the use of cover crops, the increase of the organic- matter content of the soil, and the use of limestone. Some of the re- TABLE 11. — CROP YIELDS PER ACRE FROM EECLAIMED ABANDONED HILL LAND VIENNA FIELD Year Field 1 Field 2 Field 3 Field 4 1906 1907 1908 Corn 20.4 bu. Cowpeas turned Wheat 7.9 bu. Cowpeas turned Wheat 9.6 bu. Clover .77 ton Clover 1.00 ton Corn 33.5 bu. Corn 24.4 bu. Cowpeas turned 1909 1910 1911 Clover .60 ton1 Corn 38.6 bu. Corn 37.8 bu. Cowpeas turned Wheat 17.6 bu. Cowpeas turned Wheat 15.6 bu. Wheat 8.8 bu. Clover 1.53 tons Corn 32.8 bu. Average Yields of Crops Grown Corn Wheat Clover 1906-1908 1909-1911 26.1 bu. 36.4 bu. 8.8 bu. 14.0 bu. .89 ton 1.07 tons irThe yield of clover for 1909 is estimated, the weights not having been taken because of a misunderstanding. suits obtained upon this field are recorded in Table 11. They show that such land may be reclaimed and made to produce fair crops, which tend to increase when proper care is taken to reduce washing and limestone is used in connection with a good rotation. SWAMP AND BOTTOM-LAND SOILS Deep Peat of Sand, Late Swamp and Bottom Lands (1401) Manito Field. — Table 12 records the results obtained from the Manito experiment field upon deep peat soil, where experiments were begun in 1902 and discontinued in 1905. These results are in harmony with the information furnished by the analysis of peat soil as com- pared with the composition of ordinary normal soils. Where potas- sium was applied, the yield was three to four times as much as where 482 BULLETIN No. 193 [December, TABLE 12. — CORN YIELDS IN SOIL EXPERIMENTS, MANITO FIELD: 1902 TO 1905 (Bushels per acre) Plot Soil treatment for 1902 Corn 1902 Corn 1903 Soil treatment for 1904 Corn 1904 Corn 1905 Four crops 1 None 10.9 8.1 None 17.0 12.0 48.0 2 None 10.4 10.4 Limestone, 4000 Ibs. . . 12.0 10.1 42.9 3 Kainit, 600 Ibs 304 32.4 I Limestone, 4000 Ibs. / 49.6 47.3 159.7 I Kainit, 600 Ibs ) 1 Kainit, 1200 Ibs .... f j Kainit, 1200 Ibs. ... 1 5 f Aeidulat'd bone, 350 Ibs. \ Potassium chlorid, 200 Ibs 30.3 31.2 33.3 33.9 ) Steamed bone, 395 Ibs. \ Potassium chlorid, 400 Ibs 53.5 48.5 47.6 52.7 164.7 166.3 6 Sodium chlorid, 700 Ibs. . 11.1 13.1 None 24.0 22.1 70.3 7 Sodium chlorid, 700 Ibs. . 13.3 14.5 Kainit, 1200 Ibs 445 47.3 8 Kainit, 600 Ibs 36.8 37.7 Kainit, 600 Ibs 44.0 46.0 164.5 9 Kainit, 300 Ibs 26.4 25.1 Kainit, 300 Ibs 41.5 32.9 125.9 10 None 14.91 14.9 None 26.0 13.6 69.4 Estimated from 1903; standing. no yield was taken in 1902 because of a misunder- nothing was applied. Sodium chlorid (common salt, containing no potassium) produces no results and cannot therefore take the place of the potassium salts. Applications of limestone produced no effect either alone or in combination. Sand Soil of Sand, Late Swamp and Bottom Lands (1481) Green Valley Field. — For six years experiments were conducted at Green Valley, Tazewell county, upon sand soils that easily drifted by wind when not protected by vegetation. During that time (1902 to 1907), a four-year rotation of corn, corn, oats, and wheat was prac- ticed upon a series of ten plots so treated as to secure information as rapidly as possible upon the needs of the soil. The summary of the six years' results are given in Table 13. From these results it is plain that nitrogen is the element of first importance. In fact the increase in yields was practically sufficient to cover the cost of the commercial nitrogen. Potassium is evidently the second limiting element where decaying organic matter is not provided, but the limit of potassium is very far above the nitrogen limit. Phosphorus during the six years' time produced but little increase. From the results of other experiments, it is clear that the growing of legume crops and the use of manure (and possibly limestone) on these well-drained sand soils can well take the place of commercial nitrogen. Potassium may prove profitable, at least until more organic matter is supplied. 1916] SUMMARY OF ILLINOIS SOIL INVESTIGATIONS 483 TABLE 13. — CROP YIELDS IN SOIL EXPERIMENTS, GREEN VALLEY FIELD 1902 TO 1907 Plot Soil treatment applied Corn 1902 Corn 1903 Oats 1904 Wheat 1905 Corn 1906 Corn 1907 Value of 6 crops Bushels per acre Lower prices Higher prices $134.78 112.11 401 402 None 68.7 68.2 56.3 42.0 65.4 24.9 20.1 49.7 35.9 18.3 19.0 32.9 17.8 35.3 29.5 $94.35 78.48 Lime 403 404 405 Lime, nitrogen 68.6 30.3 23.1 44.4 20.3 16.9 23.5 16.7 16.5 62.9 10.4 8.4 58.9 13.1 12.8 127.74 44.92 38.82 182.48 64.17 55.46 Lime, phosphorus Lime, potassium 406 407 408 Lime, nitrogen, phosphorus Lime, nitrogen, potassium. Lime, phosphorus, potas- sium 57.4 70.0 49.8 69.8 72.9 39.6 51.9 54.7 36.9 26.8 36.5 13.7 70.8 74.8 18.3 64.7 73.6 2Y.7 125.34 142.82 67.31 178.91 204.03 96.16 409 410 Lime, nitrogen, phosphor- us, potassium 69.5 57.2 69.8 66.1 47.8 50.0 36.2 26.5 66.4 66.0 73.6 71.9 136.47 123.97 194.97 177.10 Nitrogen, phosphorus, potassium Aver; Aver; 0 Aver, o ige gain for nitrogen. .... 23.5 6.8 -5.9 37.8 3.8 .7 22.3 3.1 3 14.3 11.2 1.5 55.0 3.8 -3 46.9 11.8 29 $73.37 17.88 .22 $104.82 25.54 .32 ige gain for potassium per nitrogen ige gain for phosphorus per nitroeren . . PERMANENT AGRICULTURE The objective which all farmers should then hold before them is the establishing of practical systems of soil management by means of which the fertility of the soil will not be impoverished but will be increased, or at least maintained, thereby making agriculture perma- nent. On some soils, such as yellow silt loam, where erosion by surface washing is carried on to a great extent, a low-grade system of perma- nent agriculture can be maintained if some use is made of legume crops in long rotations, with much pasture. This system will furnish sufficient nitrogen and organic matter and the minerals will be main- tained by the renewal of the surface soil from the subsoil by erosion. It is, however, the privilege and duty of farmers upon the common soils of the state to establish a high-grade system of permanent agri- culture and hand it down to posterity. Abundant information shows that this can be done : first, by making liberal use of legume crops in a good rotation ; second, by applying limestone liberally to soils that are acid or bordering upon acidity ; and third, by using finely ground raw rock phosphate in amounts larger than are necessary for present needs, until the soil is well supplied with the element phosphorus. For further and more detailed information regarding the soils of the state and methods for their improvement, the reader is urged to send to the Illinois Agricultural Experiment Station for any of the soil reports, bulletins, or circulars listed on the following page. 484 BULLETIN No. 193 [December, AVAILABLE PUBLICATIONS RELATING TO ILLINOIS SOIL INVESTIGATIONS No. BULLETINS 76 Alfalfa on Illinois Soils. 1902 (5th ed., 1913). 157 Peaty Swamp Lands; Sand and "Alkali" Soils. 1912. 177 Eadium as a Fertilizer. 1915. 181 Soil Moisture and Tillage for Corn. 1915. 182 Potassium from' the Soil. 1915. 190 Soil Bacteria and Phosphates. 1916. CIRCULARS 110 Ground Limestone for Acid Soils. 1907 (3d cd. 1912). 123 The Status of Soil Fertility Investigations. 1908. 127 Shall We Use Natural Rock Phosphate or Manufactured Acid Phosphate for the Permanent Improvement of Illinois Soils? 1909 (3d ed. 1912). 130 A Phosphate Problem for Illinois Landowners. 1909. 142 European Practice and American Theory Concerning Soil Fertility. 1910. 145 The Story of a King and Queen (Corn and Clover). 1910. 150 Collecting and Testing Soil Samples. 1911 (4th ed. 1916). 155 Plant Food in Relation to Soil Fertility. 1912. 165 Shall We Use "Complete" Commercial Fertilizers in the Corn Belt? 1912 (4th ed. 1913). 167 The Illinois System of Permanent Fertility. 1913. 168 Bread from Stones. 1913. 181 How Not to Treat Illinois Soils. 1915. 185 A Limestone Tester. 1916. 186 The Illinois System of Permanent Fertility from the Standpoint of the Prac- tical Farmer: Phosphates and Honesty. 1916. SOIL REPORTS No. 1 Clay County. 1911. No. 6 Knox County. 1913. No. 2 Moultrie County. 1911. No. 7 McDonough County. 1913. No. 3 Hardin County. 1912. No. 8 Bond County. 1913. No. 4 Sangamon County. 1912. No. 9 Lake County. 1915. No. 5 LaSalle County. 1913. No. 10 McLean County. 1915. NOTE. — Subsequent to the preparation of this bulletin, the following soil re- ports have been published: No. 11 Pike County. 1915. No. 13 Kankakee County. 1916. No. 12 Winnebago County. 1916. No. 14 Tazowell County* 1916. UNIVERSITY OF ILLINOIS-URBANA