UNIVERSITY OF ILLINOIS LIBRARY URBANA-CHAMPAIGN R1CULIURE LIBRARY. ftGRlCULTURfc. LlbKMtu. SOIL BUILDING WITH LEGUMES , 7 By H. J. SNIDER SEP 2 B ' UNIVERSiTY Oi : !! ' UNIVERSITY OF ILLINOIS AGRICULTURAL EXPERIMENT STATION Bulletin 539 CONTENTS Page Legumes Add Organic Matter and Build Up Nitrogen 547 Amounts of organic matter and nitrogen in the soil were higher where clover was a part of the rotation than where it was not. Dark-colored soils gained more in organic matter and nitrogen from the use of legumes than did light-colored soils. Legumes Increase Yields of Other Crops 550 Clover in the rotation meant higher yields of corn and oats and a higher protein content of the grain. Legumes Need Soil Treatment for Best Growth 553 Growing legumes under several different soil treatments showed that the more nearly complete the soil treatment was, the higher the yield of hay and nitrogen was. Legumes Differ in Ability to Improve Soils 554 Corn following a clover-alfalfa mixture yielded appreciably better than corn following soybeans and had a higher protein content. Alfalfa roots that were able to penetrate only 1 2 inches into the soil weighed as much, and so supplied as much organic matter, as the roots that went 3 feet or more into the soil, but shallow sweet- clover roots weighed much less than those that went deep. When both crops were cut for hay in September, alfalfa roots maintained their weight, while sweet-clover roots lost considerable. Soybeans Take Nitrogen From Soils 558 During the time when the soybeans were making their greatest growth, the nitrate nitrogen on a treated plot dropped from 256 pounds an acre down to 20 pounds. On an untreated plot the drop was from 132 pounds to 16 pounds. Residues of Nonlegume Crops Add Organic Matter But Little Nitrogen 559 A total of about 5 !/2 tons of organic material an acre was re- turned by a rotation of corn, oats, wheat, and soybeans on treated dark soils; on treated light soils the same rotation returned about 4 !/2 tons. On untreated dark soils the total was less than 4 tons and on untreated light soils only 1 !/4 tons. The total nitrogen re- turned on each of the fields, however, was relatively low. Urbana, Illinois June, 1950 Publications in the Bulletin series report the results of investigations made or sponsored by the Experiment Station SOIL BUILDING WITH LEGUMES By H. J. SNIDER, Assistant Professor of Soil Fertility E^GUMES ARE RECOGNIZED more and more as the key to a good soil-improvement program. They furnish generous supplies of organic matter and nitrogen. Their use enables other crops in the rotation to make better yields. And they form a cover which protects the soil against destructive erosion. Legumes can be grown abundantly and profitably on almost every acre of farm land in Illinois. They have been grown for many years on the Illinois soil-experiment fields. Some of the differences that have resulted from these years of experiment with legumes, particularly with alfalfa, sweet clover, red clover, and soybeans, are discussed in this publication. Legumes Add Organic Matter and Build Up Nitrogen Organic matter is the life of the soil. A good supply of it is necessary if the soil is to have good tilth. It keeps the soil loose and mellow so that air can get in, and it makes the soil very easy to cultivate. It also enables the soil to take up and hold water. When organic matter is depleted, the soil becomes compact and loses whatever dark color it may have had. Where there is an abundant supply of organic matter, crops benefit to the fullest extent from limestone, rock phosphate, and other mineral ferti- lizers. Organic matter is almost the entire source of soil nitrogen. Corn yields are usually highest on land that contains rela- tively large amounts of nitrogen and organic matter. This is brought out by comparing six untreated experiment fields on dark-colored soil with six on light-colored soil (Table 1). The topsoil of the six on light-colored soil contained only 1,300 to 2,600 pounds of nitrogen and 8 to 22 tons of organic matter an acre, and corn yields were only 6 to 14 bushels. The other fields had over 3,000 pounds of nitrogen and over 30 tons of organic matter an acre in the topsoil and averaged 44 to 50 bushels of 547 548 BULLETIN No. 539 Table 1. Organic Matter, Nitrogen, and Corn Yields on Untreated Soils of Twelve Experiment Fields* Experiment field . Dark-colored soils tons Ib. bu. Aledo 46.9 4 320 50 Bloomington 46. 5 4 560 50 Dixon 37 . 1 3 750 44 Carthage 34. 1 3 210 50 Clayton 33.0 3 170 47 Mount Morris 30. 3 3 480 50 Average 38.0 3750 48 Light-colored soils Oblong 22.0 2630 14 Newton 18.2 2130 6 Ewing 16.5 2030 11 Raleigh 16.2 1930 11 Enfield 12.7 1500 10 Elizabethtown 7.9 1 320 11 Average 15.6 1 920 10 a Corn yields are averages of four years. Data for organic matter and nitrogen represent amounts after fields had been in operation about twenty-five years. corn. Nitrogen and organic matter cannot, of course, be given all the credit for high yields, but they are largely responsible for a soil condition that leads to high productivity. How can an adequate supply of organic matter be kept in soil? Mainly, by growing legumes often and turning them back into the soil. A satisfactory rotation for every farm should include legumes on a quarter to a half of the cropland every year. Even on productive land legumes should be grown at least once every three or four years. On the Morrow plots at Urbana, three cropping systems have been followed since 1876: corn-oats-clover, corn-oats, and con- tinuous corn. In 1943 nitrogen and organic matter were higher where red clover has been included in the rotation than where it was not used, both on treated and untreated land (Table 2). Where the rotation has included both red clover and manure, the SOIL BUILDING WITH LEGUMES 549 level of organic matter was highest probably not much less than it was when the land was broken out of the original prairie. The more-productive dark soils in Illinois gain more in nitro- gen and organic matter from legumes and crop residues than the light soils do, according to twenty-five-year records from several experiment fields. At the end of twenty-five years dark soils which had an RLrPK treatment (residues, limestone, rock phos- phate, muriate of potash) averaged 580 more pounds of nitrogen Table 2. Composition of Soils on the Morrow Plots, Urbana, 1943 (Amounts are per acre) a -, Total rp , i Soluble Available . -, ul Available Corn-oats rotation None ions 36 2 Ib. 3 300 Ib. 14 Ib. 210 Ib. 3 390 Ib. 700 MLrP"... 39 7 4 100 1 220 310 5 570 840 Corn-oats-clover rotation None 38 4 3 600 14 230 2 890 670 MLrP* 47 8 4 500 1 280 330 6 310 1 030 Manure, limestone, rock phosphate. an acre and 6.7 more tons of organic matter than the untreated dark soils (Table 3). On the light and yellow soils under similar cropping systems, the same treatment resulted in a gain of 390 pounds of nitrogen and 4 tons of organic matter. In emphasizing the importance of legumes as a source of organic matter, we should not forget manure. For centuries farmers have justifiably placed great emphasis on its use to keep their soils productive. Its value for soil improvement is based largely on the organic matter which it adds to the soil. Where livestock are kept, manure becomes, along with legumes, an im- portant part of the soil-building program. On the Illinois soil- experiment fields it has proved as effective as legumes in increasing crop yields. 550 BULLETIN No. 539 Table 3. Organic Matter and Nitrogen" in Both Treated and Untreated Soils on Twelve Experiment Fields (Amounts are per acre) Experiment field On untreated soil On treated (RLrPK b ) soil Gain from treatment Organic matter Total nitrogen Organic matter Total nitrogen Organic matter Total nitrogen Dark-colored soils Aledo tons 46.9 Ib. 4 320 tons 61.7 Ib. 5 240 tons 14 8 Ib. 920 Bloomington 46 5 4 560 57 6 5 360 11 1 800 Dixon . . 37 1 3 750 38 3 980 9 230 Carthage 34 1 3 210 40 3 820 5 9 610 Clayton. . 33 3 170 36 4 3 620 3 4 450 Mount Morris 30 3 3 480 34 3 3 920 4 440 Average . . . 38 3 750 44 7 4 320 6 7 580 Light-colored soils Oblong . . 22 2 630 25 8 2 850 3 8 220 Newton . . 18 2 2 130 19 7 2 310 1 5 180 Ewing . . 16 5 2 030 20 8 2 440 4 3 410 Raleigh 16 2 1 930 21 1 2 380 4 9 450 Enfield . . 12.7 1 500 18 5 2 230 5 8 730 Elizabethtown . . 7 9 1 320 11 7 1 660 3 8 340 Average . 15 6 1 920 19 6 2 310 4 390 a Organic matter and nitrogen represent amounts after fields had been in operation about twenty-five years. b Crop residues, limestone, rock phosphate, muriate of potash. Legumes Increase Yields of Other Crops One way to measure the work legumes do in building up the soil is to see what effect they have on the yields of other crops in the rotation. Tests on the Morrow plots show that red clover in the rotation resulted in higher yields of corn and oats and increased the protein in the corn and oat grain (Table 4). At the same time the organic matter and nitrogen in the soil were main- tained at a considerably higher level than where legumes were not grown. In a corn-oats-clover rotation with MLrP treatment (ma- nure, limestone, rock phosphate), corn yielded 101 bushels an acre in 1943 and contained 11.4 percent protein, which is equal to 638 pounds of protein in 100 bushels of grain. In a corn-oats SOIL BUILDING WITH LEGUMES 551 rotation without soil treatment or clover, the corn yielded only 22 bushels an acre and contained only 7.8 percent protein, which is equal to 437 pounds of protein in 100 bushels of grain, a reduction of 79 bushels of grain an acre and 201 pounds of pro- tein in 100 bushels of grain where there was neither clover nor treatment. On untreated land with a corn-oats-clover rotation, the corn yield was 46 bushels and the grain contained 526 pounds of protein in 100 bushels. Thus the red clover was responsible for 24 more bushels of corn an acre and 89 more pounds of protein in 100 bushels of grain. For oats also the use of red clover in the rotation resulted in higher yields and a higher percentage of protein. On the treated land (MLrP) of the corn-oats-clover rotation, the oat yield in 1944 was 72 bushels an acre and the protein content was 235 pounds in 50 bushels. On the treated land of the corn-oats rota- tion, the oat yield was 54 bushels an acre and the protein content was 222 pounds in 50 bushels. Thus where there was no clover in the rotation, the oat yield was 18 bushels to the acre less than where clover was included, and the protein in 50 bushels of grain was 13 pounds less. Oats on the untreated land in the corn- oats-clover rotation yielded 53 bushels an acre and contained 214 pounds of protein in 50 bushels of grain; in the corn-oats rota- Table 4. Yield and Protein Content of Corn, Oats, and Red Clover From the Morrow Plots" ^nil Corn Oats Red clover treatment pSe Protein p E?racre Protein H S er p tei " Corn-oats rotation None bu. perct. 22 78 bu. 30 54 perct. 12.1 13.9 Ib. perct. MLrP b 83 10 2 Corn-oats-clover rotation None 46 9.4 53 72 13.4 14.7 3 260 16.5 6 940 15.3 MLrP b 101 11.4 Corn, 1943; oats, 1944; clover, two cuttings in 1945. b Manure, limestone, rock phosphate. 552 BULLETIN No. 539 tion they yielded only 30 bushels and contained only 194 pounds of protein in each 50 bushels, a difference of 23 bushels of grain an acre and 20 pounds of protein in 50 bushels in favor of clover in the rotation. None Hay 930 Nitrogen.... 14 RLrPK MLrP ML M (Pounds per acre from different treatments) 3,920 4,440 2,560 2,020 79 116 60 52 1,560 39 Hay Nitrogen. . . RL RLrP RL RLrP RLrPK (Pounds per acre from different treatments) 3,780 4,860 1,780 2,220 3,300 103 128 44 53 75 Soil treatment made the difference in these bundles of hay from four Illinois soil-experiment fields (each shows the growth from four square feet). Upper left, timothy-clover-alfalfa, south farm, Urbana, 1948; upper right, clover-alfalfa, Joliet, 1948; lower left, clover, Dixon, 1947; lower right, clover, Enfield, 1949. R = residues, M = manure, L = lime- stone, rP = rock phosphate, K = muriate of potash. (Fig. 1) SOIL BUILDING WITH LEGUMES 553 Legumes Need Soil Treatment for Best Growth A great many people believe that all it takes to get a satis- factory crop of legumes is to lime the land. Just how wrong this idea is can be seen from Fig. 1. Most of the cropped lands in Illinois require limestone and phosphate, and frequently potash, in order to grow the best crops of legumes. Where manure and limestone had been applied on the Joliet experiment field, a clover-alfalfa mixture in 1948 yielded 2,560 pounds of hay an acre containing 60 pounds of nitrogen. Where rock phosphate had been used in addition to manure and lime, the yields were 4,440 pounds of hay and 116 pounds of nitrogen a gain of 1,880 pounds of hay and 56 pounds of nitrogen to be credited to the phosphate. At Enfield adding muriate of potash increased acre-yields of red clover by 1,080 pounds of hay and 22 pounds of nitrogen in 1949. The first cutting of red clover on the treated (MLrP) part of the Morrow plots in 1948 yielded 6,370 pounds of hay an acre, and this hay contained 144 pounds of nitrogen. On the untreated land the yield was 890 pounds of hay and 24 pounds of nitrogen. Had both crops of clover been plowed under for soil improve- ment, the clover on the treated land would have added six times as much nitrogen and seven times as much organic matter as the clover on the untreated land. Table 5. Nitrogen in the Topsoil of Four Experiment Fields, 1916, 1935, and 1945 (Corn-oats-wheat-clover rotation) Experiment field Pounds of nitrogen per acre treatment 1916 1935 1945 Gain or loss in 29 years Newton . . None 2 960 2 920 5 240 5 380 2 130 2 420 2 220 2 490 2 580 2 790 4 600 5 400 1 940 2 380 1 980 2 440 2 300 2 500 4 480 5 480 1 980 2 560 2 060 2 460 -660 -420 -760 + 100 -150 + 140 -160 - 30 Bloomington RLrPK" . . None Raleigh RLrPK> . . None Ewing RLrPK> . . None RLrPK* " Crop residues, limestone, rock phosphate, muriate of potash. 554 BULLETIN No. 539 Over a period of twenty-nine years at four Illinois experiment fields, legumes did not grow well and were not able to maintain the nitrogen content of the soil unless the soil was treated (Table 5). On the untreated plots of each field, the nitrogen in the soil was appreciably less at the end of the period than at the begin- ning, even though clover was seeded in a four-year rotation. The same rotation on treated soil (RLrPK) at Bloomington and Raleigh during the period resulted in a small gain in soil nitro- gen; at Ewing there was practically no change. At Newton, where drainage is a problem, there was a large loss of soil nitro- gen under the RLrPK treatment, but the loss was even greater where there was no treatment. Legumes Differ in Ability to Improve Soils On the Joliet field a mixture of red clover and alfalfa in the rotation proved to be superior to soybeans in improving both yield and quality of the corn crop (Table 6). Corn following a combination of red clover and alfalfa on treated land (RLrPK) Table 6. Yield and Protein Content of Corn Grain Following Soybeans and Following Clover-Alfalfa in the Rotation (Joliet experiment field) Grain per acre following Protein in grain following Year Soybeans Clover-alfalfa Soybeans Clover-alfalfa No soil treatment 1946.. bu. 32 bu. 39 perct. 10.4 perct. 10.0 1947 44 43 8.5 9.6 1948 . . 51 63 8.9 10.1 1949 . . 36 41 9.8 10.8 Average . . . 41 47 9.4 10.1 RLrPK 8 treatment 1946.. 74 81 8.9 10.8 1947 62 76 8.5 10.2 1948 96 101 8.4 9.0 1949.. 75 77 10.1 11.6 Average 77 84 9.0 10.4 * Crop residues, limestone, rock phosphate, muriate of potash. SOIL BUILDING WITH LEGUMES 555 Differences in subsoils made the difference in the depth to which these alfalfa roots penetrated. Those on the left grew near Enfield on a gray soil with a compact, very acid subsoil. Those in the center grew near Elizabethtown on yellow hill land with a very acid subsoil. The long roots on the right grew near Mansfield on a dark-colored soil with a sub- soil only slightly acid. (Fig. 2) 556 BULLETIN No. 539 averaged 7 more bushels of grain an acre than corn following soybeans and 78 more pounds of protein in 100 bushels of grain. On untreated land the corn which followed the clover-alfalfa mixture averaged 6 more bushels of corn than the crop which fol- lowed soybeans and contained 40 more pounds of protein in 100 bushels of grain. The nitrogen supplied by the roots and straw of the soybeans was enough to increase corn yields somewhat, but was not enough to increase the protein content. The alfalfa- clover mixture was able to do both. Alfalfa and sweet clover, by nature deep-rooting plants, will The sweet clover at the left sent its roots several feet deep because it was growing on a fertile soil that had an open, porous subsoil (Spring Valley experiment field). The clover above, although grown on a well-treated soil, could not send its roots beyond about 12 inches because of a compact, acid subsoil (DuBois experiment field). (Fig. 3) SOIL BUILDING WITH LEGUMES 557 penetrate several feet (Figs. 2 and 3) when grown on land with a favorable subsoil. Where the subsoil is decidedly acid and com- pact, the main taproots will not usually go below 12 inches. But these two legumes differ considerably in the amount of growth their roots will make and the amount of nitrogen their roots will develop when the crop is grown in shallow soil. At Elizabethtown and Enfield alfalfa roots that went only 12 inches into the soil were found to weigh as much as those that went beyond 36 inches on the Mansfield field. At Enfield the roots weighed 2,870 pounds an acre, at Elizabethtown 2,910 pounds, and at Mansfield 2,880 pounds (three-year averages). The nitrogen content varied from 55 pounds an acre at Mansfield to 65 pounds at Elizabethtown and 70 at Enfield the larger amounts, strangely enough, being where the roots were shallow. Sweet-clover roots, on the other hand, varied considerably in weight and nitrogen content depending on the nature of the soil and whether they went deep or not (Table 7). Deep-rooted sweet clover on dark-colored soil at Carthage averaged, for three years, 1,740 pounds of roots an acre and 83 pounds of nitrogen in the roots. On dark-colored soil at Spring Valley the deep roots aver- aged, for two years, 3,770 pounds an acre and 176 pounds of nitrogen. But roots of shallow-rooted sweet clover on the DuBois Table 7. Dry Matter and Nitrogen in Tops and Roots of Sweet Clover at Time of Plowing Under" Field and sampling date Depth of roots Part of plant Dry matter Nitrogen Spring Valley . Deep . . . Tops Ib. 290 Ib. 17 April 5-20 Roots . . . 3 770 176 Total. . . . 4 060 193 DuBois Shallow Tops 1 490 52 April 25 Roots . . . 1 080 27 Total . . 2 570 79 Carthage, not cut in fall Deep Tops 960 46 April 13-18 Roots. . . . . . 1 740 83 Total . . 2 700 129 Carthage, cut in early fall Deep Tops 340 16 April 13-18 Roots 710 26 Total . . 1 050 42 Averages of two years at Spring Valley and three years at Carthage; DuBois data are for jne year only. 558 BULLETIN No. 539 field, a light-colored soil, produced only 1.080 pounds an acre and only 27 pounds of nitrogen. Roots of sweet clover and of alfalfa showed a very decided difference in their response to the removal of hay crops. Alfalfa roots remained about the same in bulk even though a hay crop was taken off regularly three times during the season, with the last cutting early in September. For sweet clover, however, the removal of a September cutting on the Carthage field caused the acre-weight of roots to drop from 1,740 pounds to 710, as an average of three years/ Soybeans Take Nitrogen From Soils A soybean crop contains a large amount of nitrogen, but the greater part is in the beans and is removed from the land with the beans. The part returned to the soil the straw and roots is not enough to build up the nitrogen supply. The dry matter and nitrogen in soybeans on the Joliet field were divided in this way (average for five years) : Dry matter Nitrogen Percent Pounds Percent of total of tctal Beans (24.4 bushels per acre) 1 460 28. 1 94 66.3 Tops and roots 3 740 71.9 48 33.7 Total 5200 100 142 100 Thus two-thirds of the nitrogen in the crop was in the beans, although they contained less than one-third of the dry matter. That soybeans draw on soil nitrogen can be shown by meas- uring the nitrate nitrogen (available nitrogen) in the soil during the growing season of a soybean crop. On the Joliet field in 1940 the nitrate nitrogen in the topsoil of the treated plot (residues, limestone, rock phosphate, potash) dropped from 256 pounds an acre at the beginning of the growing season, May 24, down to 20 pounds on July 20, when the soybeans had made their greatest growth. The nitrate nitrogen in the soil at different dates was: May May June July Aug. Sept. Oct. 12 24 5 20 24 27 13 (Pounds per acre) No treatment 128 132 140 16 4 14 16 RLrPK treatment.. 100 256 144 20 6 12 16 SOIL BUILDING WITH LEGUMES 559 Under conditions similar to those on the Joliet field a 25- bushel soybean crop might take up from the soil as much nitro- gen (142 pounds) as a 100-bushel corn crop (140 pounds). Residues of Nonlegume Crops Add Organic Matter But Little Nitrogen Residues of nonlegume crops are valuable in soil improve- ment because they add a large bulk of organic matter. The amount of these residues can be very large, especially where the land is treated with limestone, rock phosphate, and muriate of potash (RLrPK). As an average of several experiment fields for several years, the crops in a four-year rotation (corn, oats, wheat, and soy- beans) on treated land returned a total of almost 5 l / 2 tons of dry matter an acre and 93 pounds of nitrogen (Table 8). On untreated land the same rotation returned less than 4 tons of dry matter an acre and 60 pounds of nitrogen. In the area of light-colored soils the treated land returned almost 4J/i tons of dry matter and 76 pounds of nitrogen from the four crops. On Table 8. Amounts of Crop Residues and Nitrogen Left on Land After Harvest" (Pounds per acre) Residues General soil class Untreated land RLrPK b applied Dry matter Total nitrogen Dry matter Total nitrogen Cornstalks . . Dark 1 850 16 10 7 2 8 1 29 9 60 22 3 650 3 660 1 950 1 330 2 140 1 720 3 200 2 190 10 940 8 900 31 33 8 6 11 9 43 28 93 76 Oat straw Light . . . . . 1 120 . . Dark 1 650 Wheat straw Light . . 360 . . Dark 1 510 Soybean straw. . . . Light 230 . . Dark . . 2 680 Total Light 830 . Dark. 7 690 Light 2 540 a Averages for four experiment fields for four years, except that the averages for soybeans are based on two fields for five years. b Crop residues, limestone, rock phosphate, muriate of potash. 560 BULLETIN No. 539 the untreated soils of this area the average was IK tons of dry matter and 22 pounds of nitrogen. Cornstalks and straw are relatively low in nitrogen and so do not carry much of this element back to the soil. Analyses at the Illinois Station showed that a ton of wheat straw contained only 10 pounds of nitrogen while a ton of Ladino clover contained 71 pounds (Table 9). A ton of timothy hay contained 20 pounds of nitrogen and a ton of alfalfa hay 58 pounds. These compari- sons are typical of the relation between legumes and nonlegumes so far as nitrogen is concerned. Table 9. Chemical Composition of Farm Crops in Illinois 8 Crop Nitro- gen Pro- tein Phos- phorus Po- tas- sium Cal- cium Mag- ne- sium Corn Ib. Ib. Ib. Ib. Ib. Ib. Grain, 100 bushels .... 97.4 609 13.4 24.6 5.0 9.0 Stalks, 4,480 pounds . ... 38.1 238 4.0 66.8 24.2 18.4 Cobs, 1,120 pounds 4.6 29 .4 9.2 1.2 .7 Total . . . . 140.1 876 17.8 100.6 30.4 28.1 Oats Grain, 50 bushels 31.2 195 4.0 12.8 2.2 3.0 Straw, 1,700 pounds .... 7.3 46 1.4 47.3 6.3 2.6 Total . ... 38.5 241 5.4 60.1 8.5 5.6 Wheat Grain, 25 bushels 21.6 135 3.6 9.3 1.0 2.7 Straw, 2,000 pounds . ... 10.2 64 1.0 16.2 3.6 2.4 Total . ... 31.8 199 4.6 25.5 4.6 5.1 Soybeans Beans, 25 bushels 95.4 596 5.3 28.0 3.8 4.2 Straw, 2,840 pounds .... 31.2 195 1.4 15.0 45.7 26.1 Total . ... 126.6 791 6.7 43.0 49.5 30.3 Hay (2,000 pounds) Ladino clover 71.2 445 6.2 44.8 32.2 9.6 Alfalfa . ... 58.0 362 3.6 38.6 36.0 8.6 Birdsfoot trefoil . ... 55.0 344 4.0 33.4 32.6 11.6 Red clover . ... 55.2 345 3.4 39.6 38.2 9.2 Soybean . ... 52.0 325 3.0 18.2 28.0 17.8 Lespedeza . ... 40.4 252 2.9 18.9 17.0 5.7 Bromegrass 29.8 186 3.4 44.3 8.0 3.0 Kentucky bluegrass . ... 29.4 184 3.8 32.8 6.2 4.0 Timothy . ... 19.6 122 3.0 31.4 5.6 3.6 Redtop . ... 21.2 132 3.4 31.8 8.4 4.4 Orchard grass . ... 19.4 121 3.6 38.0 5.4 4.2 Alta fescue 29.0 181 3.6 36.0 5.5 4.1 a Averages of SO analyses except for birdsfoot trefoil, which had 20 and Alta fescue which had 10. Stalks, cobs, and straw represent the amounts which accompany the indicated yield. 20M 6-50 44071 UNIVERSITY OF ILLINOIS-URBANA