Oj^/iCo uj lijdcjjtiroincid stations Bulletin 416 LUjrnry. October, 1938 The Use of Fertilizer in the Coniferous Nursery WITH SPECIAL REFERENCE TO PINUS RESINOSA HERBERT A. LUNT dlmtmrltntt Bulletin 416 October, 1938 _ The Use of Fertilizer in the Coniferous Nursery WITH SPECIAL REFERENCE TO PINUS RESINOSA HERBERT A. LUNT Olmttt^cttatt Agricultural ^xpertmeut ^tatttm CONTENTS Introduction 723 Review of literature 723 Experimental 725 Seedbed Studies 725 Experiments at Windsor 725 Seedbed Fertilization at Peoples Forest Nursery 731 Conclusions 732 Transplant Bed Studies 732 Experiments at Windsor 732 Summary of results 737 Experiment at Rainbow . 737 Experiments at Peoples Forest Nursery 741 Soil Frame Studies 742 Windsor Frames 742 Station Frames at New Haven 745 Subsequent Response of Red Pine in the Field 748 Requirements of Nursery Seedlings and Transplants 751 Discussion 759 Summary 762 Conclusions 764 References Cited 765 THE USE OF FERTILIZER IN THE CONIFEROUS NURSERY With Special Reference to Pinus resinosa HERBERT A. LUNT JL HE DEMAND for foiest nuisery stock has been greatly accelerated in recent years by the agitation for tree-planting as a phase of soil conser- vation and flood control. In addition, the need of reforestation from the standpoint of timber and pulp wood production is becoming increasingly urgent. Without a doubt, tree planting for all three purposes will con- tinue indefinitely as a permanent feature of the Nation's conservation program. Hence, the demand for nursery stock will be maintained at a higher level than it was prior to the present decade. From the standpoint of the soil, we are faced with two problems : (a) increasing the productive capacity of old nurseries, and (b) maintaining the productive capacity of new ones; and this in the face of a diminishing supply and increasing cost of farm manure. Furthermore, it has been felt that some methods should be devised which would shorten the period of time normally considered necessary for the stock to remain in the nursery and which would also furnish larger, more thrifty plants, better able to survive when set out in the field. Whether this can best be accomplished by wider spacing, by root pruning, by fertilization, or by some other means is an important question confronting the nurseryman. In some instances continued cropping, together with the scarcity of manure, has created a real need for the use of commercial fertilizers in order to produce trees of average size, to say nothing of larger stock. As will be brought out later, continuous cropping to nursery stock constitutes a serious drain on the soil, and satisfactory results cannot be expected unless plant food is added in the form of manure or commercial fertilizers or both and, in addition, a more or less systematic rotation of crops is practiced. Many nurserymen are aware of the situation and follow a very com- mendable system for the maintenance of the fertility of the soil. Others, equally desirous of keeping up soil fertility, for some reason do not succeed, and they are faced with the problem of finding a remedy or moving their beds to other fields that are in a good state of fertility. REVIEW OF LITERATURE Experiments in soil management in the forest nursery go back at least 65 years. Von Schroeder (19) cites the work of Dulk on Scotch pine, Norway spruce and beech in 1874 and 1875, and of Schiisse on pine and spruce in 1872, 1879 and 1882. From his own experiments von Schroeder concluded among other things that, in the second year, spruce requires about as much nitrogen as does lupine and red clover, and more phosphorus than red clover. 724 Connecticut Experiment Station Bulletin 416 Rather extensive researches by Vater early in the present century were published between 1905 and 1909 (26). For the succeeding 20 years his research on the subject of forest tree nutrition and fertilization has con- tinued with greater emphasis on the forest than on nursery stock. Among other European investigators who have worked on this problem may be mentioned Helbig, 1910 (2); Schwappach, 1916 (20); Kuhnert, 1930 (5) ; Leiningen-Westerburg, 1930 (6) ; Deines, 1930 (1) ; Manchard, 1933 (7); Nemec, 1932-38 (10), (11), (12), (13), (14), (15), (17), (18); Sorensen, 1936 (21) ; Siichting, Jessen and Maurmann, 1937 (23) ; and Wetzel, 1937 (29). Materials most commonly used in fertilizer work in Europe are: ammonium sulfate, sodium nitrate, calcium nitrate, urea, Thomas slag, bonemeal, kainit, muriate and sulfate of potash, burnt lime and marl. Basalt meal is being tried as a fertilizer (3) with apparent success, especially as a supplement to manure to which it is added in the compost pile. In this country experience in nursery fertilization is rather limited, although in recent years there have been quite a number of contributions on the subject. The earlier work up to 1931 was adequately reviewed by Toumey and Korstian (25). They emphasize the importance of main- taining the organic matter content of the soil, since in producing nur- sery stock nothing is left or returned to the soil. They state that "farm manures are the most useful fertilizers for general purposes that can be used in nursery practice either alone or in combination with other materials composted with them". For commercial fertilizers they recommend the use of organic fertilizer such as dried blood, ground fish, tankage, etc., at the rate of 500 to 1500 pounds per acre, applied on seedbeds prior to plant- ing, or as a top dressing, at the beginning of the second year. The senior author had good results in growing successive crops of coniferous seedhngs on sandy loam, by applying in alternate years prior to preparation of the seedbeds the following : cow manure, 10 to 30 tons, per acre; bonemeal, 250 to 400 pounds; unbleached hardwood ashes, 400 to 800 pounds. After preparation of the beds and just prior to seeding, similar amounts of bone- meal and ashes were worked into the surface soil. The authors mention that in Europe some areas have been cropped to nursery stock continuously for 70 years. Fertility is maintained by using a compost of moor soil, ashes and nursery stock. Mclntyre and White (8) , working with Norway spruce, pitch pine and white pine, reported that "in nearly all cases the seedlings grown on fer- tilized soil were larger, better developed and heavier than those grown on the checks". In some cases dried blood produced the largest seedlings; in other cases phosphorus; in still others LNPK (lime, nitrogen, phos- phorus, potassium). Extensive experiments at the Savenac Nursery in Montana (28) with Engelmann spruce (Picea engelmannii) and western yellow pine (Pinus ponderosa) indicated a definite improvement in the rate of growth with the use of fertilizers. With the spruce, at least a year was saved over the five or six-year period formerly necessary to produce sizable seedlings. Dried blood and bonemeal or large amounts of sheep manure seemed to be most effective. The pines were benefited most by a lawn-dressing type of fertilizer analyzing 4.6 percent nitrogen and 8.8 percent phosphoric Experimental 725 acid. A blood-and-bone mixture was second best and sulfate of ammonia third. Wilde (32) found that coniferous nursery stock was definitely benefited by the application of fertilizers, provided the right amount was used. Fer- tilized plants were better able to withstand heat and drought than those unfertilized. Wilde further reports (30) (31) that certain kinds of forest duff constitute ideal fertilizing material, although, because of the im- practicability of using sufiiciently large amounts to meet the needs of the nursery stock, it is necessary to use commercial fertilizers in addition. For stimulating stunted or otherwise handicapped plants, he recommends the use of liquid hum ate. Although one finds, as he peruses the literature, conflicting reports as to the results of fertilization in the nm-sery, it is apparent by and large that nursery stock does respond to feeding. This is more evident in recent years, especially in this country, as a result, no doubt, of more carefully controlled experiments. The field of tree nutrition is only now beginning to be investigated and the possibilities for the future are most promising. Our studies in nursery-soil management and seedling nutrition are by no means finished ; but it seems ex-pedient to publish as a progress report the findings obtained so far. EXPERIMENTAL At the suggestion of Mr. H. W. Hicock, Assistant Forester at the Station, experimentation was started in 1929 to determine whether there is any way either to shorten the period necessary for a seedling to remain in the nursery, or to obtain larger plants in the usual period of time. Red pine was chosen because at that time it was being planted to a much greater extent than any other species. In a preliminary experiment in butter tubs, red pine seedlings were grown in four soils, ranging from a coarse, infertile sand to a well-fertilized, loamy sand tobacco soil. The results, given in Table 1 and Figures 108 and 109, show that red pine is responsive to differences in fertility, par- ticularly where the roots are confined as they were in this case. SEEDBED STUDIES Experiments at Windsor A series of fertihzer experiments were carried out in seedbeds at the Windsor nursery over a period of six years. The soil was Merrimac loamy sand, rather well supplied with available phosphorus as a residue from previous treatment. It was low in potash, nitrogen and organic matter. Physically it was essentially the same as the soil in tub No. 4 of the pre- liminary butter tub experiment (Table 1). The rainfall averaged 46 inches, well distributed throughout the year. 726 Connecticut Experiment Station Bulletin 416 Figure 108. Response of red pine seedlings to soil fertility. Tub 1, very coarse, infertile sand; Tub 2, medium sand from red pine plantation; Tub 3, medium sand from fertilized tobacco field; Tub 4, highly fertilized loamy sand tobacco soil. Seed planted May, 1929. Upper: May 1932, Lower: April 1933. To give full details of each experiment would require more space than the results warrant. Suffice to say that the materials used at one time or another, either alone or in combination, included the following, in pounds per acre: Ammonium sulfate 240 Potassium sulfate 188 Bloodmeal 500 Precipitated bone 325 Castor pomace 2000 Sodium nitrate 1320 Driconure' 19600 Sorbex' Fish meal 300, 600 Tankage, bone 2400 Hyperhumus- * 16335 Urea 55, 110. 220 Limestone, ground 4000 6-8-7« 1325 Milorganite' 400, 800, 1110 11-6-6 200, 400 Nitrophoska (1.5-30-1.5) 333. 1000 19-12-12 433 Organic mixtiu-e^ 350, 700 20-8-8 100, 200, 230 Peat moss 6360 , 10890, 16340 'Driconure — Trade name for a mixture of cow manure and peat moss (the latter used as bedding) dried and pulverized. -Hyperhumus — Trade name for a cultivated peat. ^Milorganite — Trade name for an activated sewage sludge. ■■Organic mixture — Cottonseed meal 40 parts, castor pomace 20, precipitated bone 6, and potassium sulfate 4. =Sorbex — Trade name for a screened peat moss. ^6-8-7 — Cottonseed meal 25 parts, castor pomace 25, potassium nitrate 15, superphosphate (16%) 30, and Ammophos "A" (13-47-0) 5. 11-5-6 — Fish meal 48 parts, ammonium sulfate 35, precipitated bone 6, and potassium sulfate 11. 19-12-12 — Equal parts of urea, Ammophos "A", cottonseed meal and potassium nitrate. 20-8-8 — Ammophos "A" 16.6 parts, urea 20.8, nitrate of soda 47.5 and potassium sulfate 15.1. Seedbed Studies 727 Figure 109. Comparison of plants from the four soils described in figure 108. A. The two largest plants from each tub. B. The two smallest plants from each tub. C. Two average plants from each tub. 728 Connecticut Experiment Station Bulletin 416 Table 1. Data Relative to Soil Fertility Experiment with Red Pine Seedlings Grown in Butter Tubs Tub No. 1 Tub No. 2 Tub No. 3 Tub No. 4 Coarse sand Medium Medium Loamy sand from barren sand from sand from from well- area R. P. tobacco fert. to- plantation field bacco field Soil Properties pH 4.38 4.40 4.71 4.79 Total Nitrogen % 0.029 0.042 0.078 0.080 Organic Carbon % 0.639 1.167 1.199 0.985 N:C 21.8 27.6 15.3 12.4 Loss- on-ignition % ' 2.25 4.16 4.50 3.45 Moisture Equivalent % 3.68 7.20 6.30 5.86 Total Colloids % 3.20 6.60 7.00 6.00 Total Sands % 90.5 86.1 85.0 86.6 Tree Counts and Measurements Oct. 15, 1930 No. of trees 21 23 25 15 (1 yr. in tubs) Length of stem. cm. 3.6 4.1 4.4 4.9 Oct. 7, 1931 New growth of leader, cm. 2.6 4.4 5.4 4.3 (2 yrs. in tubs) Total new growth (leader + smn of side branches. cm.) 8.0 10.9 11.8 13.3 Oct. 27, 1932 Total Height, cm. 14.4 18.2 26.9 26.0 (3 yrs. in tubs) Growth of leader in 1932, cm. 8.8 11.4 18.5 17.5 Table 2. Dry Weight and Needle Length of Red Pine Seedlings Following Two Seasons' Growth Fertilizers were applied prior to second season only Plot No. Treatment Dry weight 100 plants Needle Length g- Av. Relative mm. Av. 12 Peatmoss + 20-8-8 22.6 22.6 169 82.2 82.2 3 13 Fish Fish 25.6 17.6 21.6 161 61.5 55.0 58.3 6 8 4 20-8-8 6-17-13 15-30-15 23.2 17.6 13.3 18.0 134 60.6 66.4 63.5 7 Sulfate of ammonia 18.0 18.0 134 69.2 69.2 10 Peat moss 17.3 17.3 129 47.7 47.7 2 15 Milorganite Milorganite 16.6 11.2 13.9 104 50.8 36.3 43.6 1 9 14 11 5 Untreated Untreated Untreated Untreated Untreated Mean, all treatments 18.5 14.7 11.7 11.4 10.7 13.4 i6.7 100 52.2 46.3 33.9 40.9 32.5 41.2 52.5 Seedbed Studies 729 Where the fertihzer was appHed either prior to or shortly after seeding, there was considerable yellowing of the needles, and in some cases, particu- larly in the use of concentrated soluble materials, there was definite in- jury. Growth response was slight and inconsistent. On the basis of dry weight per 10 plants, the mean of all treatments was 1.30 gm., as compared with 1.22 gm. for the untreated plots. Those receiving Hyperhumus showed up best with an average of 1.47 gm. In another case, the untreated plots and those receiving Sorbex were superior to those receiving either fish, Milorganite, an organic mixture (5-6-4), or an 11-6-6 mixture. Where fertilizer treatment was not made until the beginning of the second year, the response was more satisfactory, ranging up to 69 percent increase in dry weight for peat moss plus 20-8-8 over the average of the checks, as seen in Table 2. It will be noted that there is a fairly good correlation between needle length and dry weight of the plants. It appears that fish, peat moss, and the formulae 20-8-8 and 6-17-13 were beneficial, while Milorganite and 15-30-15 were of questionable value. 200 ^ 150 cc ■ioo 50 °0 100 4 00 600 Figure 110. 200 300 NO. or PLANTS PER SQ FT. Relation between fertilizer treatment, number and weight of plants per square foot. Windsor seedbeds. The treatments were repeated, and the following spring measurements were made which are recorded in Table 3. When based on weight per 100 plants, all treatments except Milorganite produced larger plants than were obtained in the untreated plots. The 20-8-8 mixture alone and with peat moss was by far the best of the lot, producing a gain of 133 and 100 percent respectively. In agreement with the findings of other workers, the top- root ratio is higher in fertilized trees than it is in those imtreated, which is, of course, a disadvantage in transplanting. The plant with a well-de- veloped root system in proportion to top is in a better position to survive and make good growth than is one not so favored. Interesting relationships between size of plant and density of the stand are shown in Figures 110 and 111. The five checks and the peat moss treatment arrange themselves nicely below the theoretical average; the Milorganite is approximately in the average, while the other treatments are all above the average. 730 Cofinecticut Experiment Station Bulletin 416 Table 3. Effect of Fertilization on Red Pine Seedlings Three Years from Seed When Dug (Planted Spring 1932. Dug Apr. 5, 1935) Plot No. Dry we ight 100 plants Top-root ratio (T/R) No. of plants per sq. ft. Dry Weight per sq. ft. Stand den- sity g- Av. Rela- tive. Av. Av. g- Av. 12 Peat Moss + 20-8-8 65.4 65.4 200 5.31 5.31 168 168 110 110 Good 6 4 8 7 20-8-8 15-30-15 6-17-13 Sulfate of ammonia 75.8 44.1 38.8 46.6 52.9 46.6 163 143 6.43 4.02 3.91 4.75 4.79 4.75 212 280 308 240 267 240 161 124 120 112 135 112 Good Good Good Good 13 3 Fish Fish 44.2 39.7 42.0 129 4.13 4.27 4.20 276 344 310 122 136 129 Good V. good 10 Peat Moss 40.0 40.0 123 5.00 5.00 208 208 82 82 Good 11 5 9 14 1 Untreated Untreated Untreated Untreated Untreated 36.4 33.6 32.3 30.8 29.3 32.5 100 2.77 4.02 4.62 4.13 3.94 3.90 240 276 300 368 384 313 87 93 97 113 112 100 Fair Good Good Good Good 15 2 Milorganite Milorganite Mean 32.0 29.6 30.8 95 3.33 3.84 3.58 ^.38 400 476 438 299 128 141 135 115.8 Good Good 80 > :20- 0 h 0 100 200 300 NO. OF PLANTS PER SQ.FT. 400 500 Figure 111. Relation between fertilizer treatment, number of plants per square foot and Aveight of 100 plants. Windsor seedbeds. Seedbed Studies 731 Seedbed Fertilization at the Peoples Forest Nursery In the spring of 1935 experimental work was started in a limited way on the Peoples Forest Nursery at Barkhamsted. The nursery is situated on Merrimac loamy sand. Seedling beds of one-year-old plants (seed sown spring, 1934) of red pine, white pine (P. strobus), larch (Larix decidua), Norway spruce (Picea Abies), and white spruce (P. glaiica) were selected and each species received the following treatments: Plot 1 Fish 300 lbs. per A. (27 lbs. N/A) 2 " 600 " " (54 " " ) 3 12-16-12 100 " " (12 " " ) 4 " ■ 200 " " (24 " " ) The materials were applied dry on May 8 and brushed off the trees with a broom. On July 31 it was observed that white pine trees treated with 200 pounds of 12-16-12 appeared slightly greener than the untreated trees, and on white spruce the light, complete fertihzer treatment seemed slightly superior. Norway spruce appeared to be somewhat better on the portions of the bed receiving either amount of 12-16-12 than it did on either fish- treated or the no-treatment portions of the bed. Otherwise, no diiferences were noted. Early in April, 1936, it was observed that the Norway spruce trees which had received 600 pounds of fish were somewhat superior to those growing under other treatments. On the other hand, white spruce with 12-16-12 fertilizer was slightly better than with either fish or no treatments. In no case were the results at all striking, and no definite conclusions could be drawn from the work. It is quite probable that the date of application. May 8, while seemingly early enough, was still too late to be of use to the current season's growth. This is especially true in the case of fish meal which becomes available slowly. The work at this nm"sery was conducted more for demonstrational purposes than for scientific accuracy, and for this reason no actual measurements of the trees were made. It was felt that if the effect of treatment was not great enough to be detected by ocular observation, it was not significant. In the following spring fertilizers were applied (April 15, 1936) , to three species of 1-0 stock (seed planted 1935) as follows, using areas 4 by 10.9 feet (1/1000 A.) for each treatment: Norway spruce 7-6-6 Fish 400, 800, 1200 Ibs./A 500, 1000, 1500 Ibs./A 500, 1000, 2000 Ibs./A in duplicate singles White spruce 7-6-6 Fish 400, 800, 1200 Ibs./A 500, 1000, 1500 Ibs./A singles White pine Same as for white spruce On July 23 it was observed that growth on one set of treatments on Norway spruce appeared slightly inferior to the untreated portion. No differences could be noted on anv other beds. On October 27 there were 732 Connecticut Experiment Station Bulletin 416 no differences apparent except in the case of Norway spruce where the fish treatment seemed to cause shghtly poorer growth, and the 7-6-6 fer- tihzer shghtly better growth, than the untreated portions. Conclusions on Seedbed Studies From the foregoing presentation the following conclusions may be drawn, applicable to the conditions of the experiments: 1. In general, the use of fertilizers and soil- amendments has been beneficial to red pine seedlings to a greater or lesser degree. 2. There has been an inconsistency in the response of these seedlings to different kinds of fertilizer — sometimes one, sometimes another giving best results. However, there was a tendency for the organic fertilizers to be superior to inorganic types. Of the complete fertilizers used, the one high in nitrogen (20-8-8) seemed to give best results. 3. It is very easy to over-fertilize seedlings, particularly with con- centrated, soluble materials. In the light of the experiences of Mitchell (9) and others in seedbed work, it is quite probable that more satisfactory results can be obtained from the use of fertilizer if it is applied in frequent, light doses in soluble form. The seedlings grow so slowly that excess soluble fertilizer is either leached out before it is absorbed, or, if too con- centrated, it injures the seedlings. TRANSPLANT BED STUDIES Experiments at Windsor First Experiment, Main Series Commencing in the spring of 1930 a series of experiments were started to determine the response of conifers, especially red pine, to fertilization in the transplant bed. Sixty plots 4 by 8 feet were laid out at Windsor on Merrimac loamy sand, 42 of which constituted the main series of 14 treat- ments in triplicate, while the remaining 18 plots were used for extra treat- ments of one kind or another. The amount of nitrogenous fertilizer was based on 100 pounds of nitrogen per acre. The materials used in the main series and the rate of application, in pounds per acre, were: Manure (cow) 20,000 (wet) Potassium sulfate 210 Sodium nitrate 666 Superphosphate (16%) 50 Urea 220 6-8-7 1,325 The organic materials, including the 6-8-7 mixture, were applied prior to planting and worked into the soil with a hoe. All other fertilizers were applied as a top dressing, using the dry salts mixed with sand to aid in obtaining uniform distribution. Red pine seedlings, two years from seed, were planted May 5, 6 and 7, 30 trees to the row and 15 rows to the full size plot. Ammonium sulfate 475 Calnitro 500 Castor pomace 2,000 Cottonseed meal 1,500 Fish meal 1,165 Limestone 4,000 Transplant Bed Studies 733 Soil samples from all plots, representing some 16 treatments, were collected on four separate dates during the summer and tested for acidity, ammonia nitrogen and nitrate nitrogen. The findings are given graphically in Figure 112. It is to be noted that some of the treatments had a very distinct effect upon soil reaction. Both treatments containing urea and all organics except tankage caused an increase in acidity. The extreme acidity resulting from the high applications of Nitrophoska can be ascribed to the high nitrate content. The ammonia nitrogen data for the first three periods were not very reliable and should not be taken too seriously. The data on nitrates are dependable and they show quite striking differences with respect to both date of sampling and treatment. Results of Treatment on Growth of Plants, Main Series The main series will be discussed first before considering the single plots. Because the planting stock was used as it came from the beds without selection, the trees in this experiment varied greatly in size. At the time of measurement in April, 1931, it was necessary to recognize three size classes: small, medium and large. Five typical trees of each size-class were removed from each plot. The 1930 growth of leader and the needle length were measured, and the green weights of the whole plant and dry weights of both tops and roots were obtained. In order to make fair com- parison between plots, the number of rows or fractions of a row of each size class was estimated and these values were used in calculating the weighed totals. This latter value is the sum of the products of the measure- ment in question and the number of plants of each plant size. For example, the data for the green weight of the plants in plot 1 are as follows : 12 3 4 Average Class green weight No. of rows Weighed value per plant (2 x 3) Small 1.7 2.0 3.4 Medium 9.4 11.0 103.4 Large 24.2 1.0 24.2 Weighed total 131.0 The data so calculated are found in Table 4. It must be borne in mind that these data are only of limited value because of the original variation between plots. Under the conditions of the experiment it appears that the soluble materials were most effective in influencing growth. Eight of the 14 treatments showed a positive response, while 5 were negative. That soluble fertilizers stimulate top growth rather than root development is shown by the ratio of tops to roots. Shoot growth was well correlated with dry weight, but little can be said for needle length in this respect. Shoot growth and needle length were compared statistically and found to have a correlation of .702 ± .024, based on 198 measurements. 734 Connecticut Experiment Station Bulletin 416 120 lOO 80 60 40 20 PH ^' CHECK lO zz 100 6 60 S 6 0 4 40 3 20 2 0 Ne. i' \ \ ^ W- UREA 6-8-7 UREA PK PH NH3~N — - NO3- N 6-8-7 tL NaNOs /,\v CALNITRO 'A. AM.SULF. 120 100 6 60 5 60 •4 40 3 20 A, ,-/ & CAST. POM. I I xcT X zz 100 80 60 40 20 0 X^ MILORG. y 7 f y -26 '^ZB '28 ^24- t:-,--. C.S.M. Nitrophoska y y ^ y ^26 ^28 ^Za 'ZA FISH Nitrophoska y y y y '26 '2S 'Za ^24 TAhJKAGE Nitrophoska y y y y ^26 '28 '28 •24 Figure 112. Soil tests, Windsor transplant beds. 1930. Transplant Bed Studies 735 Table 4. Results of Fertilization of Red Pine Transplants Windsor, Main Series, Season of 1930 Arranged in order of decreasing weight of whole plant Weighted totals (except needle length) Treatment No. of plots Total drj g. T weight Relative Tops Roots Shoot growth cm. Needle length cm. 252.7 166 3.99 75.5 7.52 239.1 157 4.70 67.2 8.59 213.1 140 3.57 68.4 8.27 208.7 137 3.95 73.3 8.29 171.3 113 3.31 60.6 7.98 162.1 106 3.13 58.9 8.39 160.4 105 3.46 61.1 8.18 1.58.2 104 3.30 58.3 8.53 152.4 100 3.36 57.5 8.19 132.0 87 3.53 42.8 7.53 126.6 83 2.91 58.2 7.95 119.0 79 3.62 50.3 8.30 116.1 77 3.13 52.4 8.45 102.7 68 3.02 49.3 8.57 i7U.8 Sodium Nitrate + K Ammonium Sulfate + K Calnitro + K K Urea + K Urea + PK Urea Manure Untreated 6-8-7 -I- lime Castor pomace -|- K 6-8-7 Fish + K Cottonseed meal + K Mean* 3 3 3 5 3 2 8 2 3 3 3 50 *Obtained by averaging all plots; not simply an average of the figures given above. Table 5. Measurement of 1931 Growth, Red Pine Transplants Windsor, Main Series. (Planted 1931) (Average of 3 plots for each treatment) Treatments Relative Fish Muriate of potash Nitrate of soda Castor pomace Cottonseed meal 16-15-17 Manure Urea + K Sulfate of ammonia Urea 16-15-17 + L Urea PK Check Calnitro , 8.1 7.9 7.8 7.8 7.7 7.7 7.7 7.7 7.7 7.6 7.6 7.6 7.3 7.3 111 108 107 107 105 105 105 105 105 104 104 104 100 100 Second Windsor Experiment with Transplants, Alain Series All plants in the main series (beds 1-42) were removed. The beds were spaded and fertilized as in the original application in 1930, except that in place of the 6-8-7 mixture, a new "forest formula" 16-15-17*, was used at * 16-15-17: Potassium nitrate 16 parts, potassium chloride 20, sodium nitrate 16, Ammophos "A" 32, urea 16. 736 Conneclicul Experiment Slallon Bulletin 416 the rate of 75 pounds of nitrogen per acre. Two-year-old red pine seedlings which had been hand-selected to insure uniformity were carefully planted May 11-18, all by one man. In the fall 10 average trees were measured to determine the amount of growth put on in the current year. As we see in Table 5, the differences were small, the average heights ranging from 7.27 cm. to 8.10 cm., or an increase of 11 percent. For the next year, 1932, treatments were repeated on the basis of 75 pounds of nitrogen per acre for the organics, and 100 pounds for the soluble fertilizers, the latter in two applications. KCl was used in place of K2SO4, and a 20-8-8 mixture was substituted for the 16-15-17. In late September the total height was taken of all trees in every other row of every plot. Later, 25 average trees were cut out and dry weights obtained. The data, contained in Table 6, show that, based on height of plants, the organic fertilizers were superior to the inorganics; but the dry weight figures show a somewhat different picture, some of the soluble materials being equal or superior to the organics. In all cases, however, the treated plots produced larger trees than the untreated. In April, 1933, all trees were removed; but before this was done 35 average trees from the triplicate plots of 8 different treatments were saved for planting out. The trees were selected by measurement based on the previous fall's results. The land was re-worked, fertilized as in previous years, and planted to oats and later to buckwheat. The yields of both crops were closely correlated with pH of the soil, the sodium nitrate and the limed plots being the best, and the sulfate of ammonia plots the poorest. Table 6. Height and Dry Weight of Red Pine Transplants, Fall, 1932 Windsor, Main Series. (Planted 1931) (Average of 3 plots for each treatment) Treatments Height Dry wt. per tree (tops only) cm. Relative g. Relative Fish Cottonseed meal Castor pomace Urea Urea PK Manure 20-8-8 + L. UreaK NaNOs K 20-8-8 Calnitro Ammonium Sulfate Check 26.1 25.3 24.8 24 2 24.0 23.8 23.7 23.7 23.6 22.9 22^8 22.5 22.3 22.0 119 115 113 110 109 108 108 108 107 104 104 102 101 100 7.92 7.64 7.72 8.16 7.24 6.96 7.. 32 7.80 7.72 6.40 7.40 7.04 7.84 6.28 126 122 123 130 115 111 117 124 123 102 118 112 125 100 Peat Moss 19,060 (air dry) Reel pine duff 14,720 " " Sulfur 200 Tankage, bone 3,000 666, 1,333, 2,666 Transplant Bed Studies 737 Results with Other Materials on the Single Plots As stated on page 732, of the 60 plots laid out and planted in 1930, 18 were single plots used for trying out a variety of materials which could not be included in the main series. These materials and their rates of appli- cation were : Bloodmeal 1,000 Hyperhumus 32,670 Magnesium sulfate 300 Milorganite 2,224 Nitrophoska (15-30-15) At the end of the first season, only one treatment, 666 pounds of Nitro- phoska, gave results definitely superior to those on the untreated plots. The gain was 30 percent. The two poorest treatments were red pine duif, 52 percent below the checks, and the high application of Nitrophoska, 63 percent below. It will be recalled that the latter resulted in a very high degree of acidity in the soil. These trees were not removed at the end of the first season but were carried through until the fall of 1931, with the treatments essentially the same as in 1930 except Nitrophoska which was not repeated. Final meas- urement in the fall did not reveal any striking results one way or another. It was noted, however, that plots which received a complete fertilizer the current year were somewhat superior to those treated only in the pre- ceding year. In the refertilization of the plots on April 18, 1932, sulfur, magnesium sulfate and red pine duff were dropped, and Hyperhumus or Milorganite used in their stead. Only the lowest application of Nitrophoska was used. The plots were then planted with hand-selected, two-year pine seedlings. Measurements made in the fall of 1932 and again a year later revealed considerable inconsistency in the growth response to the various treatments. The maximum increase was 46 percent, but in many cases the gain was slight. Yields of an oat crop which followed the removal of the pines showed very little correlation with the growth of the latter. Summary of the work on the Windsor transplant beds The foregoing presentation of the results obtained in the transplant beds at Windsor indicates a general response to fertilizers, ranging up to 46 percent better than the untreated plots. Frequently,Ldifrerences due to treatment were hardly noticeable in the field and could be ascertained only upon actual measurement. There was much inconsistency in response to different kinds of fertilizer and the results obtained do not warrant any positive conclusions on the matter. Transplant Bed Experiment at Rainbow In order to obtain additional data on the response of red pines to ferti- lization, a transplant bed was established on coarse sand at the Rainbow 738 Connecticut Experiment Station Bulletin 416 plantation. In April, 1933, a fairly open area was cleared of a few gray birch and young- spruce and pine, and then plowed and harrowed. On April 28 it was laid off into 48 plots, each 4 by 5.5 feet, and fertilized as follows : Amount Fertilizer Amount Plot Nos. Treatment per plot per acre N per A S- lbs. ft)S. 1-16-32-47 0 Check 2-17 33-48 N Blood Tankage 230 1005 75 3-] 8- 34-37 P Precipitated bone 83 363 4-19-35-38 K Sulfate of potash 48 210 5-20-36-39 PK /Precipitated bone 83 363 \Sulfate of potash 48 210 6-21-25-40 NK /Blood Tankage 230 1005 7.5 1 Sulfate of potash (Blood Taniage 48 210 7-22-26-41 NPK 230 1005 75 ■1 Precipitated bone [Sulfate of potash 83 363 48 210 8-23-27-42 NPK Formula (20-8-8)* 57 249 50 9-21-28-43 NH3 /Sulfate of ammonia 54 236 50 t Sulfate of potash 48 210 10-13-29-44 NO3 /Nitrate of soda 72 315 50 \Sulfate of potash 48 210 11-14-30-45 NPK Nitrophoska (15-30-15) 76 332 50 12-15-31-46 N Dried ground fish 203 887 75 *For composition of 20-8-8, see p. 726. Early in May 14,400 hand selected, two-year red pine seedlings were planted, 30 trees per row and 10 rows per plot. Incidentally, the 24,540 trees (nursery-run stock), taken from the nursery, graded out as follows: Selected trees 60.4 percent; large discards 4.6; small discards 35.0. It is believed that these figures represent better than average nursery bed run, for the section used was chosen for its uniformity. Because of injury from some of the treatments, notably ammonium sulfate and sodium nitrate, the amount of fertilizer applied in 1934 was only half that of the original application. Thus, the amount used was equivalent to 25 pounds of N in the inorganic fertilizers, and 37.5 pounds in the tankage and fish treatments. In 1935 the amount was increased to two-thirds of the original, or 33.3 pounds of inorganic N and 50 pounds of organic N. In order to prevent over-crowding during the last year, every other tree was cut out in November, 1934, and the trees removed from each plot were dried and weighed. Measurements taken in October 1935 concluded the work on this particular transplant bed, and the plants were removed the following spring. Results The first season there was very little difference in height of the trees on the various plots, but there was a marked difference in stand, the nitrate of soda and the sidfate of ammonia plots showing definite injury. The results for the second season are given in Table 7, in which the treatments are arranged in order of decreasing total dry w^eight per plot. Here we find the organics alone and phosphorus alone superior to the checks, with a gradual decrease to the ammonium sulfate plots which were Transplant Bed Studies 739 Table 7. Effect of Fertilization on Red Pine Growth Rainbow, 2nd Season, 1934. (Planted 1933) (Order based on total dry weight per plot) Total dry wt. Dry we ght per Growth per plot 100 trees Av. in 1934 Needle Plot height t of all length No. Treatment cm. plants in mm. g. Relative g- Relative each plot 2 Tankage 797 117 634 114 21.0 2960 90.3 12 Fish 760 112 572 103 23.8 3092 92.0 3 P 727 107 576 103 22.9 2438 95.5 8 20-8-8 687 101 619 111 23.2 2641 97.4 1 Check 681 100 5.58 100 22.4 2749 97.9 5 PK 655 96 527 94 99 9 2171 108.1 6 Tank. + K 649 95 601 108 22.3 2419 113.7 11 Nitrophoska 610 90 571 102 22.1 2539 105.6 7 Tank. PK 592 87 581 104 21.8 1934 108.2 4 K 570 84 492 88 20.7 1948 104.7 10 NaN03 + K 519 76 545 98 20.9 1485 107.1 9 Am. Sulf. + K 374 55 582 104 20.2 1463 120.9 Mean 635 572 22.2 2320 i03.U Mean(omitting 9 and 10) 673 2 189 distinctly poorer. Dry weight per 100 trees shows little correlation with the weight for the whole plot. On the other hand, average height per tree shows remarkably good correlation with total dry weight, although, in agreement with Nemec's results (15), height varies much less than weight. Both the sum of the heights and the total sum of the growth are well correlated with total dry weight. It should be noted that in every case except one the check plots were superior to the mean, even when the ob- viously injured plots 9 and 10 are omitted from the mean. Needle length is inversely related to height and growth. Results for the 1935 season are found in Table 8. It is interesting to note that the check plots dropped to tenth place relative to the sum of Table 8. Effect of Fertilization on Red Pine Growth Rainbow, 3rd Season, 1935. (Planted 1933) (Order based on ■$ of heights) No. Treatment S heights. Av. for each plot 5 growth in 1935 Av. height each plant Av. growth per tree in 1935 cm. Relative cm. cm. cm. Relative 5 PK 2529 113 4322 35.5 13.3 130 8 20-8-8 2522 113 4155 34.8 11.6 114 2 Tankage 2488 111 3572 36.8 12.8 126 12 Fish 2467 111 3243 34.9 11.1 109 3 P 2384 107 3425 33.8 10.9 107 6 Tank + K 2305 103 3859 36.1 13.8 135 7 Tank + PK 2284 102 4168 35.8 14.0 137 4 K 2244 101 3664 32.7 12.0 118 11 1 Nitrophoska Check 2243 2234 101 100 3347 2808 33.6 32.6 11.5 10.2 113 100 10 NaNOs 1780 80 3018 32.5 11.6 114 9 Am. Sulf. 1639 73 2911 32.6 12.4 122 Mean 2260 35^1 3U.3 i2.i 740 Connecticut Experiment Station Bulletin 416 heights, and to the twelfth place from the standpoint of 1935 growth. The 20-8-8 treatment advanced from seventh place in 1933, to fourth in 1934, and second in 1935. The correlation between height of the individual tree and the sum of the height measurements is good, indicating that tree size as well as stand density is influenced by the treatment. Soil tests, made from time to time, revealed no definite correlation with growth of the plants, although the effect of treatment was generally registered in the tests. The data in Table 9 are typical. Table 9. Soil Tests by the Universal Rapid Method Rainbow Transplant Bed— Oct. 10, 1934 (Pounds per Acre) Treatment Check Tankage P K PK Tankage + K Tankage + PK 20-8-8 Am. Sulf. + K NaNOs + K Nitrophoska Fish Plot No. 1 2 3 4 5 6 7 8 9 10 11 12 pH* 4.65 4.90 5.10 4.80 5.10 5.15 4.80 4.70 4.65 4.70 4.60 4.80 NHs-N NO3-N 7.5 10.0 10.0 7.5 7.5 7.5 6.0 6.0 7.5 10.0 8.0 7.5 3 4 5 5 <2 <2 <2 2 2 <2 20 25 125 15 175 30 75 40 20 25 40 35 K 125 150 150 150 150 175 150 125 150 175 175 150 Al 400 400 350 400 85 100 200 250 300 150 200 175 *Deteriiuned electrometrically. Of special interest is the amount of nitrate accumulation obtained when soil from some of the treatments was incubated 26 days. This is shown in Table 10. All of the treatments tested caused an increase in nitrification Table 10. Effect of Soil Treatment Upon Nitrification During A 26-Day Period of Incubation Rainbow Transplant Bed — July, 1934 Plot Treatment NO3-N in ppm. Initial Final Gain 0.8 3.0 9 9 0.8 4.3 3.5 1.5 6.0 4.5 1.7 10.3 8.6 1.0 6 4 5.4 1.0 13.1 14.1 1.0 18.8 17.8 8 9 10 11 12 Check Tankage 20-8-8 Am. Sulf. + K NaNOs + K Nitrophoska Fish greater than that in the untreated soil. Of particular significance is the low and relatively uniform nitrate content present on the date of sampling, indicating the active absorption of nitrates by the plant roots. A signifi- cant accumulation in the soil occurs only when root competition is elimi- nated. Transplant Bed Studies 741 In this experiment the average length of needles, collected from the mid-point of the current season's leader, was correlated with growth as follows : Coefficient of correlation (r) between 1933 needle length and 1933 height of plant +.815 ± .065 1933 1934 1934 1934 1934 1934 " " " +.496+ .146 1934 " " " —.952+ .018 1934 total weight of plot —.873 + .046 1934 growth, :$ all plants, in each plot — .837+ .059 1935 growth, av. per tree +.463+ .153. Thus we see that there is a good relationship between needle length and height, weight, or growth of plant in the same year, although it is direct in 1933, the first year, and inverse in 1934. The existence of an inverse relationship during the same year would suggest a direct relationship be- tween needle length one year and growth the next year. However, the data on hand do not bear that out. In order to make adequate comparisons with growth, it is necessary to take into consideration the number of needles as well as the length. Since the number was not determined, it is not possible to explain the apparent discrepancies in the foregoing correlations. Early in June, 1935, there appeared a defmite yellowing of one-half to three-fourths of the needle length of the needles on about 10 plots, in- cluding all plots receiving sulfate of ammonia. Apparently this condition was associated with inadequate soil moisture, for it disappeared a few weeks later, following about two inches of rain. Summarizing the results of this particular work, it may be said that on this soil the response of red pine transplant stock to fertilization was not significant until the third season. Of the various materials compared, the organics — both tankage and fish — when used alone, were found near the top of the list in every case. The 20-8-8 mixture also made a fairly good showing. There was a relationship between needle length and growth during the current season. All treatments caused an increase in nitrifi- cation upon incubation of the soil. Experiments at Peoples Forest Nursery On May 8, 1935, fertilizers were applied as top dressings to 2-0 stock which had been put in the transplant bed the preceding month. The species and the treatments given were as follows: Red pine, white pine, Scotch pine, Norway spruce, white spruce, Douglas fir, and hemlock. Treatments: a Fish 400 lbs. /A. b " 800 c 12-16-12 150 d " 300 Observations made July 31 indicate that all species except red pine, hemlock and Douglas fir showed some benefits from fish applications, especially in the heavier amounts. 742 Connecticut Experiment Station Bulletin 416 In the spring of 1936 a somewhat more extensive experiment was carried out as follows: Transplant beds, planted with 2-0 stock, spring, 1936. a. Applied before planting Norway spruce 7-6-6 500, 1000, 1500 Ibs./A. Fish 800, 1600, 2400 " " 800, 1600, 3200 " " White spruce 7-6-6 500, 1000, 1500 " " Fish 800, 1600, 2400 " " b. Applied as top dressing after planting White pine 7-6-6 400, 800, 1200 " " Fish 500, 1000, 2000 " " Norway spruce 7-6-6 400, 800, 1200 " " Fish 500, 1000, 2000 " " All treatments were applied between April 7 and 16. No actual measurements of the trees were made for the reason that if the effect of treatment was not apparent to the eye, it was deemed not significant. This does not mean, however, that no increase took place. Further reason for not taking measurements was the fact that the trees were not selected and hence were for the most part quite irregular in size. On July 23, the treated white pine trees were greener and slightly larger than were the untreated trees. No other differences could be detected. Thus, the work of two seasons at this nursery yielded us little in the way of positive results from the use of fertilizers. The amounts used covered a range wide enough easily to come within the requirements of trees. It is interesting to observe that as much as 3,200 pounds of fish to the acre, equivalent to about 288 pounds of N, was not injurious. SOIL FRAME STUDIES Windsor Frames Ten concrete soil frames, each measuring 32 inches by 10 feet or 26.66 square feet, were filled with Enfield v.f.s.l. which rested on the natural subsoil of the Merrimac series below 20-inch depth. The initial soil treat- ment was as follows : Nos. 1 & 6 NK 2 &7 NP 3 & 8 PK 4 & 9 NPK 5 & 10 NPKX These amounts provided approximately 80 pounds of N, 120 of P2O5 and 90 of K2O per acre. A crop of tobacco was grown in 1931 and then, in the middle of April, 1932, 72 hand-selected red pine seedlings, 2-0 stock, were planted in each frame. In the fall, the total height of each tree was measured, and two fasicles (pairs) of needles were collected from the mid- point on each stem. Treatment in 1933 was identical to that of the pre- ceding year. fCalurea 150 fts./A IKNO3 200 [Precipitated bone 316 1 Calurea 75 ICalnitro 278 /Precipitated bone 316 \K2CO3 140 fCalurea 150 KNOs 200 (Precipitated bone 316 Cottonseed meal Castor Pomace 880 374 Precipitated bone IK,C03 223 108 Soil Frame Studies 743 In 1934 every other tree was cut out and weighed. Five trees from each plot were pulled out in order to get some idea of the root system. Because of this reduction in number of trees, fertilizer applications were altered as follows: Calurea, KNO3 and Calnitro were reduced by one- third; Cottonseed meal and castor pomace reduced by one-fourth. In the fall, measurements were made as usual. From time to time the soil was sampled for reaction and fertility tests. On April 2, 1935, all trees in the outside rows, and every other tree in the center row, were cut out, leaving six per frame. As the trees by this time were getting beyond the age of transplant bed stock, consideration of their later development is reserved for another publication. The results from the first three growing seasons are given in Tables 11 and 12. Unfortunately, there were no untreated frames for comparison. This omission is of less consequence in the case of a crop like tobacco which would do practically nothing without fertilization. But for pines which have low requirements, it is desirable to determine whether or not the treatment is beneficial. One is never certain whether the best growth is actually superior, or whether it is merely normal, and the other treatments are below normal. There was one more disturbing factor in connection with these frames. An apple tree near frame No. 1 offered so much competition that the pines nearest the tree were definitely handicapped. The apple tree roots were able to penetrate the frame from below, and even though the roots were severed once, the original handicap could not easily be overcome. As seen in Table 11, PK was the best treatment in every case, and NK Table 11. Height, Needle Length and Soil Tests Windsor Soil Frames. Red Pine Growth Soil Tests Av. cur- Av. (Pounds per acre Treat- ment weight cm. rent season needle length Date NH3- NO3- cm. mm. pH N N P K Ca M Fall PK 11.9 107.8 8/22/32' 6.0 8 20 20 1932 NPKX 11..5 90.8 5.5 4 6 10 1st NPK 11.1 80.8 5.4 2 16 6 season NP 10.8 76.9 5.4 4 16 10 NK* 10.1 57.2 c 0 4 8 5 NK** 10.5 55.0 D,Z Mean*** li.l 82.7 Fall PK 28.2 16.3 118.2 10/30/33^ 5.2 12 0 13 400 525 1933 NPKX 2-1.7 13.2 143.4 4.9 13 0 10 410 500 2nd NPK 22.6 11.5 144.3 5.0 10 0 15 500 .500 season NP 21.8 11.0 129.0 4.7 18 1 18 160 350 NK* NK** 17.2 16.1 7.1 5.6 146.8 150.1 4.6 18 1 10 360 250 Mean*** 22.9 il.8 136.3 FaU PK 58.7 30.5 128.7 4/11/34- 5.2 33 7 18 175 400 425 1934 NPKX 55.0 30.3 120.1 4.9 40 15 18 175 400 500 3rd NPK 54.6 32.0 130.5 5.0 33 5 20 175 400 375 season NP 47.3 25.5 128.8 4.9 30 5 20 100 575 375 NK* 45.8 28.6 130.3 4.8 20 1 10 100 300 500 NK** 37.9 21.8 126.2 4.6 50 2 10 150 4m 500 Mean***\ 52.3 29.^ 127.7 Frame No. 6, not affected by apple tree. Frame No. 1, close to apple tree. In no case is Frame No. 1 included in the mean. ■ All results by quick test. ^ pH determined by quinhydrone method. All other results by quicR test. 744 Connecticut Experiment Station Bulletin 416 was the poorest. Because of the pronounced effect of the apple tree on the NK frame No. 1, its results are not averaged in with the others. For all three seasons the identical order was maintained with respect to height, although in the third growing season, the NPK treatment made the most growth. Needle length was strikingly variable the first year; but was very uniform the third year. The acidity of the soil varied inversely with the yield. Since red pine prefers an acid soil it is believed that this correlation with acidity is merely a coincidence. This soil was low in available phosphorus and the growth of the trees substantiates the findings of the soil tests. The weights of the trees removed from these frames are given in Table 12. In part A, the green and dry weights of approximately 30 trees cut off at the ground line yield reliable data as to the amount of tree growth up Table 12. Weight of Red Pine Trees Removed from Windsor Soil Frames A. April 16, 1934 Average of 5 pulled trees Cut Trees Dry weight, g. Treatment Av. weig ht per tree Tops No. of Green Dry Tops Roots Total trees g. g- Roots PK 31 46.1 18.6 98.0 19.0 117.0 5.16 NPKX 29 45.1 18.0 95.5 19.6 115.1 4.87 NPK 31 36.2 ]4.4 113.0 19.5 132.5 5.79 NP 31 29.2 11.0 70.2 17.2 87.4 4.08 NK* 29 24.0 9.8 68.0 14.5 82.5 4.69 NK** 30 17.7 7.1 64.0 10.5 74.5 6.10 Mean*** 36. i iU.U 88.9 18.0 W6.9 4.92 Green wt. Dry wt. 2 48 2 04 R. April 2, 1935 Treatment Frame No. No. of trees Green wt. per tree g. Av. g- NPK 4 9 29 29 169. 41,. o r 169.6)169.5 NPKX 5 10 30 28 153.7il6^-^ PK 8 3 28 30 170.01,30 Q 149.8/^^9 -9 NP 7 2 29 24 142. 2\ 142. 2 97.5; .... NK Mean 6 1 30 28 133.0\133.0 89.8/ .... 153.7 *Frame No. 6 not aifected by apple tree. ** " " 1 close to apple tree. ***In no case is Frame No. 1 included in the mean. Soil Frame Studies 745 to April, 1934. There was little difference between PK and NPKX, but trees on the other treatments averaged considerably smaller. The data on root size were taken from only five trees, and since the roots were merely pulled out, parts were broken off and lost. It so happened that trees from the NPK treatment were largest. The proportion of tops to roots was highest in the NPK and lowest in the NP. Other observations have shown an indication for the untreated plots to have the lowest proportion of tops to roots, which of course is a desirable characteristic in field planting. Additional trees were cut out a year later, and the green weights of those removed are given in Part B of Table 12. Here we see that NPK has pro- duced the largest trees, and PK has dropped to third place. All the way through, NK has produced the smallest plants, indicating the need for P in this soil when the other elements are supplied in abundance. The com- peting effect of the apple tree definitely extended to frame No. 2, so that the data from neither 1 nor 2 are included in the average. The fact that NP was inferior to PK in its effect upon growth indicates one of two things: either the soil is deficient in both P and K in relation to the soil nitrogen ; or the amount of N added was too great in proportion to the soil potassium. Comparison of needle length to growth reveals that in 1932 the height increased slightly with needle length of that year. In 1933 growth was al- most a perfect lineal function of the 1932 needle length. But the needle length in 1933 showed no correlation with growth that year, and only a slight indication of an inverse relationship with height of plants and with growth in 1934. Needle length in 1934 showed no correlation with 1934 growth. In the absence of needle counts, no conclusions can be drawn. From the foregoing results it is evident that the deficiency of one ele- ment in the soil is reflected in the growth of red pines, provided the other necessary elements are present in abundance. However, the experiment does not tell us whether or not the trees would be benefited by the applica- tion of merely enough of the deficient element to balance the other elements naturally in the soil. Station Frames at New Haven A set of concrete soil frames on the Experiment Station grounds, which had been used some seven years for a wide variety of crops, was turned over to the writer in the spring of 1934 for use in tree studies. There are 48 frames, each measuring 25 by 25 inches, with the walls extending about 21 inches below the surface of the soil. There is no artificial bottom. The frames were filled with Cheshire fine sandy loam taken from the vicinity of the Experiment Station grounds. Treatments were as follows: 0, P, K, PK, N, NP, NK, NPK; and the same repeated with lime. The hme was applied just once, the fu-st year of the installation; all other treatments were made annually through 1933. Commencing in 1934 (the first year with trees) the treatments were given in two applications, half of the usual amount being applied in late April, and half in October. In order to avoid building up an accumulation of undesirable residue, materials which would leave no unwanted ions were used. These materials were urea, at the rate of 50 pounds of N per acrfe, phosphoric acid (H2PO4 85%) at the rate of 100 pounds P2O5 per acre, and potassium acetate (KC2H3O2), 50 pounds K2O per acre. 746 Connecticut Experiment Station Bulletin 416 After spading under the rye which had been sown the previous fall as a cover crop, the soils were fertilized and then one series was planted to hand-selected red pine, 2-0 stock, 30 trees per plot. Red oak and sugar maple were planted in the other two series. Discussion of these species, however, will be reserved for another place. Results The trees were measured for total height in October, 1935, after two seasons' growth. Then, in the following spring, before growth commenced, they were thinned out so as to leave only nine per plot. The cut trees were weighed both green and dry. These results are given in Table 13. On Table 13. Effect of Treatment on Growth of Red Pine. New Haven Soil Frames. Spring 1936 Fall 1935 Soil Tests, April 1936 Dry Green Total Wei Av. jht Total We Av. ght Total height lbs. per acre per for per for Treat- tree plot tree plot cm. pH NH3-N P K Ca Al ment g- g- g- g- NK 11.85 237 26.8 536 23.1 5.25 5 15 200 <400 >500 P 10.63 202 24.7 470 21.5 5.38 10 200 150 600 400 K 9.52 200 21.7 453 22.6 5.73 10 25 600 650 375 0 9.47 199 21.5 453 21.9 5.50 15 30 125 550 375 N 9.45 189 21.2 424 18.6 5.10 <5 20 <100 <400 >500 NPK 9.14 128 21.1 295 21.1 5.15 5 300 250 450 425 PK 9.05 190 21.1 443 21.7 5.68 6 175 500 850 175 NP 8.90 178 20.2 405 18.3 4.85 15 120 125 3500 100 Av. 9.75 i90 22.3 455 21.1 5.33 9 108 256 925 356 LNP 8.38 134 19.3 310 20.3 5.85 15 120 125 3500 100 LNK 8.21 115 18.6 261 18.8 5.96 <5 30 500 4500 175 L 7.95 159 18.3 365 21.0 6.39 5 30 100 5000 50 LP 7.90 158 18.2 364 20.3 6.10 <5 300 150 5000 50 LK 7.57 159 17.0 358 19.8 6.38 <5 30 500 5000 35 LN 7.40 148 17.1 342 19.1 5.80 5 15 175 1750 200 LPK 7.21 137 16.5 314 17.9 6.32 5 275 600 5000 35 LNPK 7.06 113 16.4 263 18.4 6.03 6 175 500 4500 100 Av. 7.71 UO 17.7 322 19.5 6.10 6 122 331 ^281 93 the basis of dry weight of the cut trees, which is the most reliable figure given, all of the limed plots produced smaller trees than the unlimed plots. This could be seen by careful ocular observation before the trees were re- moved. It should be noted also that only three of the treatments were superior to the untreated plot, and only two of these were significant: NK, 25 percent, and P, 12 percent. Perusal of the soil test data shows wide variations in the amount of available plant nutrients, but no correla- tions whatever with size of plant except that of pH. All of the limed plots were less acid than the unlimed, although the differences in some cases are very slight. Measurements of total height were again made in the fall of 1936 ; and in April, 1937, all trees were removed, taking as much root as possible without attempting to get all of the fine roots. The data in Table 14 show the results of the final season's growth. 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