TEXAS AGRICULTURAL EXPERIMENT STATION R. D. LEWIS. Director. College Station, Texas Tfiullefzh 73/ I "All" VETGII, BIIR GLWER MID 0AT$ 144 Sad-Builclm; 6mm FDR (FDTTUN MID W“ ll TEXAS E. B. Reynolds, P. R. Johnson and H. F. Morris T ( fbecemfiw I950 n] ~ ‘~<:,>"_ ‘)‘;a The TEXAS AGRICULTURAL AND IVIECHANICAL COLLEGE SYSTEM 1f; ems GILCHRIST, Chancellor [Blank Page in Original Bulletin] Digest Plowing under hairy vetch fertilized with superphosphate and potash for soil improvement increased the average yields of cot- ton and corn about 40 percent at College Station for the 11 years, 1937-47. Vetch increased the average yield of cotton 75 to 84 percent and practically doubled the yield of corn at Tyler. Plowing under vetch also increased the average yield of cotton about 75 percent at Nacogdoches. The results at College Station. ‘show that vetch must be fertil- ized with phosphate and potash to obtain satisfactory yields 21 of vetch and cotton. Fertilized vetchfurnishe-d enough nitrogen for cotton at College Station, as the application of commercial nitrogen to cotton following the vetch did not make additional l increases in the yield. The plowing under of fertilized vetch produced somewhat larger yields of cotton than the use of 400 pounds of a 4-8-4 fertilizer per acre at Tyler and Nacog- doches. Hairy vetch was a better green-manure crop than oats at Tyler and oats or bur clover at Nacogdoches. v . v11»: The elfects of plowing under hairy vetch lasted more than a year. Corn planted on land where vetch had been plowed under i a year before produced 40 percent larger yields than corn on ' untreated land at College Station. At Tyler, vetch practically doubled the yield of corn. Similar results were obtained with l cotton at Nacogdoches. In general, vetch added enough nitrogen t0 the soil for cot- i; ton, which followed vetch. Vetch produced average yields of about 12,000 pounds of green matter per acre at College Sta- a tion, 19,000 pounds at Tyler and 9,000 to 10,000 pounds at i Nacogdoches. The 12,000 pounds of green matter at College Sta- -- tion contained about 100 pounds of nitrogen per acre. Hairy vetch planted on beds made a slightly larger yield than vetch planted flat on plowed or unplowed land at College Station. There were, however, no significant differences in the yields of cotton following the vetch managed in different ways. The results indicate the vetch should be planted on beds or planted broadcast and the land then bedded so the vetch will emerge on the beds, especially on soils that are not well drained, such as the Lufkin and similar soils. On well-drained sandy loam soils at Tyler there was no advantage of using beds at any time. ._ The growth of vetch was approximately the same with or with- out beds. Grain drill seeding equipment for planting vetch favlored flat planting. Flat-planted vetch was also easier to turn un er. Larger soil and water losses occurred at Tyler where vetch followed cotton than where it followed corn. CONTENTS Digest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ,. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Methods 0f Conducting the Work . . . . . . . . . . . . . . . . . . . . . . . .“ Results Obtained at College Station . . . . . . . . Y . . . . . . . . . . Yield and Nitrogen Content of Vetch . . . . . . . . '. . . Yield of Cotton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yield of Corn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Results Obtained at Tyler . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yields of Green-manure Crops . . . . . . . . . . . . . . . . . . .. Yield of Cotton.‘ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yield of Corn . . . . . . . . . . . . . ..- . . . . . . . . . . . . . . . . . . . . .. Results Obtained at Naco-gdoches . . . . . . . . . . . . . . . . . . . . . Yields of Green-manure Crops . . . . . . . . . . . . . . . . . . . Yield of Cotton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Residual Elfect of Green Manure on the Yield of Cottdf 1k Methods 0f Managing Vetch . . . . . . . . . . . . . . . . . . . . . . . . ~z Results Obtained at College Station . . . . . . . . . . . , . . . .; Results Obtained at Tyler . . . . . . . . ._ . . . . . . . . . . . . . . . Elfect of Vetch and Crop Sequence on Soil and Water Loss S’ Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i; References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ,;.. i §l3ULLETIN 731 ' DECEMBER 1950 nmnv mun, nun 0mm mm om 144 SaiZ-Bualdim; Guam ron cotton m coma m rexns E. B. Reynolds, P. R. Johnson and H. F. Morris* XPERIMENTS WERE BEGUN in 1936 to determine the value of winter legumes for soil improvement, including methods of their management, in East Texas. The work was conducted at the Main Station, College Station; Substation No. 2, Tyler; and Substation No. 11, Nacogdoches. Reports on the progress of the work have been made from time to time in progress reports and in annual reports of the Texas Agricultural Experiment Station (1, 2, 3, 4, 6, 9). Sev- < eral articles on the chemical phases of the work have been pub- lished in scientific journals (5, 7, 8, 10). The detailed results ‘of these experiments, however, have not been published as a j Whole. For this reason, the results are brought together in this i bulletin so that they will be available to Texas farmers in one publication. METHODS OF CONDUCTING THE WORK _, The scope and methods of conducting the work varied some- iwhat at the three locations. The main objective, however, was ‘ to determine the value of legumes for soil improvement and es- pecially whether the plowing under of legumes would supply 1 the nitrogen required for satisfactory yields of cotton and corn. To determine this, the legumes were inoculated and seeded in the fall on a well-prepared seedbed and fertilized with what were considered adequate amounts of superphosphate and pot- ash. The legumes were plowed under in the spring and cotton g or corn was planted on the land. The yields of cotton and corn from these plots were compared with the yields of these crops on unfertilized plots and with the yield from plots which received a complete fertilizer. A *Respectively, professor, Department of Agronomy, College Station, Texas; superintendent, Substation No. 2, Tyler, Texas; and horticulturist, f gubstation No. 2, formerly superintendent, Substation No. 11, Nacogdoches, y, exas. 6 BULLETIN 731, TEXAS AGRICULTURAL EXPERIMENT STATION RESULTS OBTAINED AT COLLEGE STATION The Work at College Station included only hairy vetch asgf soil-improving crop because tests with winter legumes 1931 to 1936 showed it was the best legume available for purpose (3). Vetch was grown during the winter and was lowed by cotton in the summer until 1945, when a 2-year ~¢ tion of cotton and corn was established. In the revised pro .f vetch preceded cotton and corn followed cotton. <11 This experiment with soil-improving crops was conducte, Lufkin fine sandy loam soil. The Lufkin soils occur mostli the southern and southwestern parts of the East Texas m; country, although they are found in areas scattered througa}, the region. They are not naturally very productive but, careful treatment, produce moderate yields of general >- crops. - Five following treatments were used. These treatments I arranged at random and repeated six times. ft 1. Vetch alone (not fertilized). " 2. Vetch and 500 pounds of 0-8-4 fertilizer per acre pounds applied to vetch in the fall and 200 pounds to cotto the spring). j 3. Vetch and 500 pounds per acre of 4-8-4 fertilizer. l pounds of 0-8-4 were applied to vetch in the fall, and 200 p0,, of 0-8-4 and all of the nitrogen to cotton in the spring.) 4. 500 pounds of 4-8-4 fertilizer applied to cotton in the sp I 5. No treatment. The fertilizer for the vetch was broadcast or drilled o? near the surface, and plowed under. The soil was then di preparatory to planting the vetch. Hairy vetch was plante the prepared seedbed in October or early November. The , having first been inoculated with the proper bacteria, was ~~' with a grain drill at the rate of about 35 pounds per acre; vetch was allowed to grow until about March 15 or 20 and then plowed under. Cotton was planted on this land abo month later. Yield and Nitrogen Content of Vetch A Although we are concerned here mainly with the effe plowing under vetch on the yield of cotton and corn, it i: sirable to know how much vetch was plowed under and much nitrogen it contained. i‘ As shown in Table 1, fertilized vetch produced an av yield of 11,926 pounds of green matter per acre and the, fertilized vetch, 7,771 pounds, for the five years 1937-41. amounts of green vetch contained 2,759 and 1,786 v-ij. air-dry matter per acre, respectively. This difference in yi‘, ‘ SOIL-BUILDING CROPS FOR COTTON AND CORN IN TEXAS . 635:0 3 0:0 ac: was ion 2 00:33.2“. noun e05 ~ 3 mm no mwwe 02m 3 @253 ha E8 _ 3 2 0.. n35 03m 3 2055a as 10033 no 1250 05:: :33? $5.509...“ 0maa0>c 9.5 D5 :00>$0A 30.?» E oocouommw 0:8 .32 MHfi-HMEQ», . 2: 03 N3. 2; w: 03, 3N 22 S; 3N 2.: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . £028.55.» n SN 2w 0S b5 5 m3 wfi 2N i: S» 3N . . . . . . . . . . . . . . . . . . . . . . . . . ._.3::..8== =30.» 3 m5 =2 22.. 2.» I: ~NN 3m 0mm fiu =3 wbN . . . . . . . . . . . . . . . . . . . . . . . . 410% 0.. mfiilca =3 mm 3N w“: AZ». 2N 3 $2 i.» 2K 22 mm» 5N . . . . . . . . . . . . . . 41m-.. .3 225:5 25 Hid =8; a» =5 22 01.3 QQN fin MNN 3.. 3» I: “S. 5N . . . . . . . . . . . . . . 410% 0.. ZZZ-on i5 i=0 43$» 50m fiugaobfl: *0mu.~0>< $2: n22 3.: i 3.2 O Ni: :2: $3 2x: 32 $2 0.5.0 00a “£050.02? ~02. 0000.55 “m. _ _ _ 21E: éofifim 000:5 an :39» Ema: fir; 26812;» 0.=EmE.=00.~w E 0.8m :5 0:: w: 2.55m E E0300 .00 32% N 030B 3.» £5 3 E: 2K; r2.“ afid 0.0.0.2 . . . . . ..§¢.6>< “KIM S.» wh N3 25d 25w :3.» 15.2 . . . . . . . . . 3S2 3..." .5.» S mb i»; 02.6 mum; 3H0 . . . . . . . . . . 10:: NQJ" hmfi hm 0w 2;; 5M6 w-.N m3 m . . . . . . . . . . . .522 S.» 33m w» i: 084.. $50 Nma.N wflfifi . . . . . . . . . . . . I33 Nwfi w?” 5 .2: uNTN find QAZXN 3i: . . . . . . . . . . . . .52: E5 :00 =3 =3 EH03 EH03 EH03 330B woumzfiofi-D u0nflflh0k vmimmfauzi w0n=3~0h nhuii. c0050 Twig 5002b =3 002.00.02.00 =3 wQEE-Qm is» =0 a30> Tunis E :0 A30.» E 0.3a .8.- qc 0.3a :5 :30.» .5505“: u: 0uafi-0Pr0m c0922: u: mwcuoh u: 32:25 E E0; 3:52 5.53m 000:5 3 =89» E nwwabi we 05.050 was :33» n3 w: 0.3m 00a 30m? A 0110B 8 BULLETIN 731, TEXAS AGRICULTURAL EXPERIMENT STATION i highly significant. These figures are for the top growth only. Tl amount of roots was not determined in this experiment. The nitrogen content of the air-dry vetch was fairly unifort. throughout the 5 years and averaged about 3.85 percent. The addition of fertilizer had no significant effect on the per centage of nitrogen in the vetch. During the 5 years, the fert, lized vetch contained, on the average, 105 pounds of nitrog; per acre and the unfertilized vetch 68 pounds. These amoun” are equivalent to the nitrogen in 656 and 425 pounds, resp. tively, of nitrate of soda or 318 and 206 pounds, respectivel of ammonium nitrate. » The vetch supplied an abundance of nitrogen for the f0 lowing cotton crop- The soil where the fertilized vetch W’ plowed under contained about twice as much available nitrogi (nitrate) during the active growing season of cotton as the uh fertilized soil or the soil receiving 500 pounds of 4-8-4 fertiliz per acre (7). 1 Yield of Cotton The yields of cotton obtained in the experiment duringtlif 10 years, 1937-46, are given in Table 2. Poor and irregul Figure 1. Right, cotton following fertilized vetch produced an aver _ yield of 270 pounds of lint per acre for 10 years, 1937-46, a College Station. Left, unfertilized cotton made an avera. yield of 195 pounds of lint. Q SOIL-BUILDING CROPS FOR COTTON AND CORN IN TEXAS 9 tands caused by insects and seedling diseases resulted in low r1: nd unreliable yields in 1943. Although the 1943 yields are given the table, they should not be considered in arriving at con- lusions. f: The soil that received an application of 500 pounds of 4-8-4 ertilizer to cotton made a slightly larger average yield of lint 273 pounds per acre) than the other treatments, Figure 1. The ield of this treatment was not significantly greater than the ields from the treatments of vetch and 4-8-4 fertilizer and vetch i nd 0-8-4 fertilizer. The yields from these three treatments, how- I ver, were significantly larger than the average yields obtained rom the soil on which unfertilized vetch was plowed under and Tfrom the untreated soil. _ The plowing under of unfertilized vetch made a slight, but Hot significant increase in the yield of cotton during the 10- ear period. Where phosphate and potash were added along ith nitrogen, good yields were obtained. s"; The results show, therefore, that the plowing under of a good j op of vetch supplies plenty of nitrogen for cotton. As men- ioned earlier in this bulletin (7), the soil where fertilized vetch plowed under contained about twice as much available nitro- en as the untreated soil or the soil which received 500 pounds _f 4-8-4 fertilizer per acre. Despite this fact, however, the treat- f“ of 500 pounds of 4-8-4 fertilizer made a slightly larger iverage yield of cotton. This indicates that some factor other an the amount of available nitrogen (nitrates) in the soil ‘.5: ited the yield of cotton. Yield of Corn i The experiment was revised in 1945 and half of the land was lanted to cotton and half to corn, thus making a 2-year rotation p_'f cotton and corn. The corn followed the cotton and received lnly the residual effects, if any, of the vetch, except that the lots of cotton which received commercial nitrogen in previous Years also received nitrogen for corn in 1945 and 1946. The treat- "pm used and the yields of corn obtained are given in Table 3. Table 3. Yield in bushels of shelled corn per acre in green-manure ‘ experiment with hairy vetch at College Station, 1945-46 Treatment per acre Bushels per acre Average percent increase over untreated soil For cotton For corn 1945 1946 Average* i; ‘i’ iry vetch and 500 a pounds of 4-8-4 . . . .. 20 pounds of nitrogenT 41.9 21.5 31.7 . 39.0 ppairy vetch and 500 ounds of 0-8-4. .. .. none 42.5 21.4 32.0 40.0 _~I pounds of 4-8-4. . . 20 pounds of nitrogenT 41.9 16.2 29.0 27.2 etch, unfertilized. . .. none 37.3 15.5 26. 4 15.8 . ntreated . . . . . . . . . . -- none 34.6 11.0 22.8 The difference in yield between any two average treatments shown must equal or exceed (15.5 bushels to give odds of 19 to 1, and 7.9 bushels to give odds of 99 to 1 that such dif- erence is real and not due to chance. fNitrogen supplied in nitrate of soda or ammonium nitrate. 10 BULLETIN 731, TEXAS AGRICULTURAL EXPERIMENT STATION As will be noted, the residual effect of the treatments on i yield of corn were quite marked in 1945 and 1946. Low yiei were obtained in 1946 but the residual effect of the fertilkj vetch practically doubled the yield of corn. During the 2 ye ,_ the residual effect of the fertilized vetch produced an aver increase of 40 percent in the yield of corn. . ~ The addition of 20 pounds of nitrogen per acre as a side-dress’ did not increase the yield in either of the 2 years. Normally,‘ would be expected that the use of nitrogen as a side-dress? would increase the yield materially. Conditions were fairly fav, able’ for corn in 1945, but the added nitrogen had no appreci effect on yield. RESULTS OBTAINED AT TYLER The work at Tyler was conducted on Boswell fine sandy lo_, in a 2-year rotation of cotton and corn during the 6 y_ 1938-43. The hairy vetch and oats were seeded separately plowed land in the fall, usually in October. The inoculated ve f seed and oats were planted with a combination grain-fertil’? drill and 400 pounds per acre of 0-8-4 fertilizer were appliedfi< the drill with the seed. The vetch and oats were plowed u‘ the following spring, about the latter part of April. Cotton‘ planted on the land about 2 or 3 weeks after the vetch_ "5 plowed under. Corn followed on the land the second year and -, ceived only nitrogen, except as indicated in Table 5, which giij. the treatments in detail. > Boswell fine sandy loam occupies extensive areas in Northe Texas. The results obtained with soil-building crops at should be applicable generally to this and associated soils in.’ region. " Yields of Green-manure Crops Although we are concerned primarily with the yields of co and corn following the green-manure crops of vetch and o" we also are interested in knowing how much organic ma was plowed under in the vetch and oats. Hairy vetch made an average yield of 18,819 pounds of gr matter per acre during the 6 years, 1938-43, as shown in 4. The green vetch contained 3,429 pounds of air-dry matf) b. w- Table 4. Pounds per acre_of green and air-dry matter in the tops of v“, and oats plowed under 1n green-manure experiment at Tyler, 1938. Vetch Oats Year Air-dry matter Green matter Air-dry matter Green 193s . . . . . . . . . . . . . . . . . . . . . 4. see 21, 67o 1,049 7.52:? 1939 . . . . . . . . . . . . . . . . . . . .. 1 222 6,110 1 025 7“ 1940 . . . . . . . . . . . . . . . . . . . .. 4 e40 17,121 s23 a 758? 1941 . . . . . . . . . . . . . . . . . . . .. ‘3 657 24,383 2 232 9 920; 1942 . . . . . . . . . . . . . . . . . . . .. 2 768 18 453 l 115 5 9 1943 . . . . . . . _ . . . . . . . . . . . .. a e24 19 177 310 1 s Average . . . . . . . . . . . . .. 3,429 18,819 1,102 5 5 SOIL-BUILDING CROPS FOR COTTON AND CORN IN TEXAS 11 ‘Pa amount of vetch contained about 130 pounds of nitrogen r acre, on the basis of the nitrogen content of vetch at College uftion. Apparently the vetch supplied enough nitrogen for ‘e cotton. During the same period oats made an average yield 1,102 pounds of air-dry matter per acre, which is equivalent f 5,527 pounds of green matter. Yield of Cotton 5' Soil where vetch was plowed under produced significantly rger average yields of cotton during the 6 years, 1938-43, ‘an soil on which fertilized oats were plowed under or soil ‘leated with 400 pounds of 4-8-4 fertilizer per acre, Table 5. e 2 treatments of hairy vetch produced average yields of and 283 pounds of lint per acre, which were 75 percent _id 84 percent, respectively, more than the yield from the un- ilized soil. Plowing under oats increased the average yield j cotton only 22 pounds, or 12 percent, during this period. je use of 400 pounds of 4-8-4 fertilizer per acre produced 228 unds of lint per acre, or 48 percent more than the unfertilized il. This yield is significantly larger than the yield of cotton a the unfertilized soil. These results indicate that the 4-8-4 fertilizer did not supply qlough nitrogen for cotton on this particular soil, whereas ferti- ' d vetch probably furnished enough nitrogen. At College Sta- T». on Lufkin soil, the 4-8-4 fertilizer produced as large yields i, cotton as the fertilized vetch. These differences in the results a the two soils may be due to greater leaching of nitrogen in 4-8-4 fertilizer on the Boswell soil at Tyler. Yield of Corn _No cover crop was grown following the cotton and preceding @- corn. The corn received the residual effects of the green : ures and fertilizers and, in addition, 100 pounds per acre Jsulfate of ammonia, except as shown in Table 6. The open- llinated Yellow Surcropper variety was used. Higher yields higher fertility levels, and perhaps more response to the added ogen, could be expected from adapted hybrids, which were H; in commercial production when the experiment was started. g: iety tests of corn conducted at the Tyler station since this feen-manure work was begun have shown consistently that apted hybrids yield significantly more than the Yellow Sur- pper variety. e vetch and other treatments-produced significant increases the yield of corn. For example, corn on the vetch plots which u not receive nitrogen made an average yield of 27.4 bushels p‘ acre for the 3 years, 1941-43, as compared with 30.2 bushels ere the corn received 100 pounds of sulfate of ammonia per i e. These yields indicate that the vetch residues furnished 1;. enough nitrogen for corn under the particular conditions. N 0 I T A T S T N E M I R E P X E L A R U T L U C I R G A S A X E T 1. 3 7 N I T E L L U B 12 602020 9H 02. HO: 500 mflflh Um 0950.10 95D Q H O fi-M ‘OOOKO HQ 1500 HWUE 5.00:0 0020500000 QMNNQPU Qkfi MFG §0&q0h UmLmTh-mflm 00000000302002”. o2; 0.4% N62 n22 0:02 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........0:0Z mm nJN vNN vNN N.oN 25.550 .2. 000.220 2.52.: 2:: . . . . . . . . . . . . . . . . . . . . . . . . . .5550 o0 v.02. 2.52.: ca. 00 0. RN NdN NéN 0.0.0 2:05:00 2. 0.0.220 2.525 2: . . . . . . . . . . . . . . . . .=0._ 5 010.0 .2. 2.525 2... 1:0 200 00 QQN 0.00 0.00 v.00 0:0Z . . . . . . . . . . .=0u :0 Tw-c .2. 2.52.: cow 2:0 i000.» 220i 000 N . =0 000 NSN 0.3 25.550 .2. 000.220 2.52.: 2.0 . . . . . . . . . . .=0.~ :0 0-0.: 2. 2.525 i... ~50 £000.» 055 200500000 *0u000>< n02: N13 ~13 00.2.0 00H 5.02.0 00h 0: 00.2. 0000005 uGQOhQ-H 0000 000 20050000? .2132 .0022. 00 00000 a2? 00005200500 000200550000 5 0000 000 500 2.0220000 .2. 20.0005 5 22% d 030E .0052? 00 02. 2.: 0:0 2.00 2 00:02.22. c000 00:0 2 3 00 2.02.0 0Z0 3 2.52.: 0m 1:0 .2 o0 2 .2. 222. 03M 00 2.525 bu 2.00000 .2. 222.0 00:5 5.250 050500000 0000050 005 2:0 00000500- 32.» 5 00:000..Ew 04H... \ .... $0 N02 ~02 NN ZN 2N 20 05.2 ... . .... 11150500000 02 0.. mNN =00 m2 0.. 0N». 000 3N 022.550 .2. 000.220 .2. 2.52.0 2: 5.02.0 00 0-0-0 2. 2.5220 25v N2 000 000 02 m» emN NNN aNN 25.550 .2. 000220 2. 2.5220 2.0 . . . . . . . . . . . . . .. . . .:0.0 5 v-04. 2. 2.52.0 22.0 0:0 200 2. 000 000 mmN S: 02. 2.0 mmN 05.2 . . . . . . . .. 1:00 5 .10.-.. 2. 2.522- ocv 0:0 2000.0 2.20m m» AFN 80 000 05 02. 2.0 ~NN 022.550 .2. 000.220 2. 02.5220 2: . . . . . . . . ...=0._ :0 0.0-0 .2. 2.52.0 ca. 1:0 A000.» 2000i 5.300 *0w000>< 0.50 N3: :2: 2.2 2.00 002 :.2.0 2.2 5.02.0 00H 2.0250020: 002. 0000005 50000m 0000 .60 .0:050000H mw-wmmfi .02.»? 00 00005000500 00500550000 5 0000 000 5.02.0 0:: .2. 2.525 5 E0; .0 0200B SOIL-BUILDING CROPS FOR COTTON AND CORN IN TEXAS 13 f! the other hand, the plots that received 4-8-4 fertilizer for otton and 100 pounds of sulfate of ammonia for corn produced nly 21.7 bushels per acre. It is not apparent from the data btained why this treatment did not produce as large a yield i= corn as the other treatments of nitrogen. The plowing under of oats fertilized with 400 pounds of f-8-4 fertilizer per acre did not increase the yield of cotton _ery much. The application of 100 pounds of sulfate of ammonia er acre to these plots for corn, however, practically doubled v he yield, Table 6, and gave better results than the plots receiv- g g 4-8-4 fertilizer. a RESULTS OBTAINED AT NACOGDOCHES f‘ The work with green manures for cotton at Nacogdoches was Qconducted on Ruston and Kirvin fine sandy loams during the 5 ears, 1941-45. Several combinations of green manures and ertilizers were used, as shown in Table 7. Each treatment was Table 7. Pounds 0f green matter per acre plowed under in green-manure experiment at Nacogdoches, 1941-44 ' ; Treatment per acre 1941 1942 1943 1944 Average 4Hairy vetch alone . . . . . . . . . . . . . . . 8,960 8,360 8, 560 8, 120 8,500 Zflairy vetch and 400 pounds of " 0-8-4 applied to vetch . . . . . . . . . l2 , 560 ll , 140 ll , 100 8,220 10 ,755 EI-Hairy vetch and 400 pounds of a‘ 0-8-4 applied to cotton . . . . . . . . . 8 , 380 9 , 800 8 , 500 10 ,020 9 , 175 Hairy vetch and 400 pounds of 0-8-0 applied to vetch . . . . . . . . . 11 ,400 9,900 8,420 8,820 9,635 filiant bur clover and 400 pounds I of 0-8-4 applied to clover . . . . . . . * 1 , 500 5,680 9,300 5,493 §0ats and 200 pounds of 4-8-4 ap- p» plied to oats and 200 pounds of 4-8-4 applied to cotton . . . . . . . . . 2, 920 3,080 1 ,320 4, 580 2,975 lkNo yield of bur clover obtained the first year of planting. ieplicated six times. The legumes were planted in the fall, al- lowed to grow during the winter and plowed under in the spring. otton was planted on the land about 2 or 3 weeks after the 1 een manures were plowed under. Cotton was practically a fail- jure in 1945 because of poor stands resulting from seedling fdiseases. 0' Yields of ‘Green-manure Crops , Hairy vetch, giant bur clover and oats were used as soil- building crops in the experiment at Nacogdoches. The vetch gproduced average yields of 9,000 to 10,000 pounds of green matter per acre, or about twice as much as bur clover and gthree times as much as oats, Table 7. After the first year, apparently it made little difference in yield of vetch whether the jpllllosphcazte and potash were applied directly to the vetch or to e c0 on. 14 BULLETIN 731, TEXAS AGRICULTURAL EXPERIMENT STATION Yield of Cotton The results obtained at Nacogdoches, like those at Tyle show that hairy vetch in combination with superphosphate a s? potash was more effective than bur clover, oats or a comple fertilizer. For example, the treatment of hairy vetch and l1‘ pounds of 0-8-4 per acre made an average yield of 286 poun_ of lint per acre for the 4 years 1941-44, as shown in Table Table 8. Acre yields in pounds of lint cotton per acre in green-mania’: experiment at Nacogdoches, 1941-44 a Treatment per acre 1941 1942 1943 1944 Averag" 3 Hairy vetch alone . . . . . . . . . . . . . . . . . . . . . . . 153 193 327 238 Hairy vetch and 400 pounds of 0-8-4 applied ' to vetch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255 231 388 272 Hairy vetch and 400 pounds of 0-8-4 applied 1 to cotton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218 235 369 279 Hairy vetch and 400 pounds of 0-8-0 applied to vetch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272 217 367 228 Giant bur clover and 400 pounds of 0-8-4 applied to clover . . . . . . . . . . . . . . . . . . . . . . 37' 88 361 262 Oats and 200 pounds of 4-8-4 to oats and 200 pounds of 4-8-4 to cotton . . . . . . . . . . . 51 127 298 196 400 pounds of 4-8-4 applied to cotton... . . . 65 148 393 217 No treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 82 351 180 *The difference in yield between any two average treatments shown must equal or e 31 pounds to give odds of 19 to 1, and 41 pounds to give odds of 99 to 1 that such difie F is real and not due to chance. This yield was significantly larger than the yields of cotton fr, the soil where bur clover and oats were plowed under and l~,{ yield from the unfertilized soil. There was, however, no 81",, cant difference between the yields of cotton from the two ve treatments in which phosphate and potash were included. The combination of oats and 4-8-4 did not increase the y! of cotton appreciably. The combination of bur clover and I _ made an average yield of 187 pounds of lint per acre, W was only 15 percent more than the yield of lint from untr soil. This low average yield apparently was due to the fact y bur clover was practically a failure in 1941 and 1942 and c0: quently did not add much nitrogen to the soil. In 1943 and "' when the bur clover made more satisfactory growth, the y of cotton from this treatment were about as large as from the treatment of hairy vetch and 0-8-4. 7 Residual Effect of Green Manure on the Yield of" Cott As stated previously, work with green manure for co was conducted at Nacogdoches from 1941 to 1945. The if manure crops _and fertilizer treatments were discontinued at 1945. Cotton, however, was planted on these plots in 1946f 1947 to determine whether the previous treatments had f; %eski)1‘ a . ice-year rotation of corn (vetch), cotton and oats (cowp-eas). The vetch was planted in ‘i’; fall after the corn was harvested and was plowed under the following spring as a soil- g_ roving crop prior to planting cotton. Cowpeas were planted after ‘oats and were {gigwcd under in preparation for corn the following spring. " glks Were undisturbed. This was probably because the land pgf: ~ plowed for vetch and no trash or residues were left on the face to prevent soil losses while the vetch was developing a iotective cover. - a qThe crop residues from continuous corn without a cover crop ere’ less effective in preventing soil loss than continuous cotton rotated corn residues plus vetch. The continuous corn residues ere plowed under in January or February and the soil was bare ‘fr a longer time. é: 22 BULLETIN 731, TEXAS AGRICULTURAL EXPERIMENT STATION t SUMMARY Experiments with hairy vetch for soil improvement w’ conducted at College Station, Nacogdoches- and Tyler ove i period of 11 years, 1937-47. The work at Tyler also inclu, oats as a green-manure crop. Giant bur clover and oats :5? - were included in the work at Nacogdoches. l The plowing under. of vetch ‘fertilized with superphosp ‘y and potash produced as large yields of cotton as an applica] of 500 pounds of 4-8-4 fertilizer per acre on Lufkin fine sa loam at College Station. The vetch supplied enough nitrogen‘ cotton, as an application of additional nitrogen to the c0 p, a following the vetch did not increase the yield. Vetch, howe‘, must be fertilized with phosphate and potash for satisfacj results. ~ Six methods were used at College Station to determine I suitable methods of handling vetch. Vetch planted on =_ made slightly larger yields than vetch planted flat on plot or unplowed land. There were, however, no significant d'g ences in the yields of cotton following the vetch handled ifizi? several ways. The results indicate that vetch probably ,0.’ be planted on beds or broadcast and then the land bedded so; vetch will emerge on beds, especially on slowly-drained _ such as Lufkin. On the other hand, there was no advan at Tyler of planting vetch on beds on Boswell fine sandy l which is a well-drained soil. i Plowing under hairy vetch fertilized with phosphate and T ash produced significantly larger yields of cotton than 400 po per acre of a 4-8-4 fertilizer on Boswell fine sandy loam at g ‘ Oats fertilized with an 0-8-4 fertilizer did not increase the of cotton appreciably. The residual effect of hairy vetchi second year practically doubled the yield of corn. The three treatments of fertilized hairy vetch produced: nificantly larger average yields of cotton than Giant bur cl oats or 400 pounds of 4-8-4 fertilizer per acre on Ruston; Kirvin fine sandy loams at Nacogdoches. The plowing und oats fertilized with 4-8-4 fertilizer did not increase the yi cotton. Plots on which vetch and» bur clover were plowed y annually from 1941 to 1945 produced significantly larger of cotton in 1946 and 1947 than the other treatments. - Vetch produced an average yield of about 12,000 poun green matter per acre at College Station, 19,000 poun Tyler and 9,000 to 10,000 pounds at Nacogdoches. The pounds of green matter at College Station contained abou pounds of nitrogen. These amounts of vetch, when plowed vi supplied enough nitrogen for the following crop of cotto, addition, the vetch had a residual effect during the secon '7 third years. Larger soil and water losses occurred at Tyler where followed cotton than where vetch followed corn. a '* n. z. ‘é , SOIL-BUILDING CROPS FOR COTTON AND CORN IN TEXAS 23 REFERENCES Johnson, P. R. Experiment Station results with legu111es for soil improve-t ment. Texas Agricultural Workers’ Association Proceedings 18tl1 Annual Meeting, pages 27-32. 1946. Reynolds, E. B. Hairy vetch for soil improvement. Texas Station Progress Report 639. 1939. Reynolds, E. B. Winter legumes for Texas. Texas Station Progress Report 646. 1939. Reynolds, E. B. Winter legumes as soil-improving crops for cotton. Texas Station Progress Report 716. 1941. Reynolds, E. B., W. R. Cowley and J. C. Smith. Soil reaction as affected by plowing under hairy vetch. Journal of the American Society of Agronomy, 37: 5°9‘513- 1945- Reynolds, E. B. and J. C. Smith. Vetch improves soil fertility in East Texas. Texas Station Progress Report 1024. 1946. Reynolds, E. B. and J. C. Smith. The effects of plowing under hairy vetch on the yield of cotton and on Lufkin fine sandy loam. Journal of the American Society of Agronomy, 38: 13-21. 1946. Reynolds, E. B. and J. C. Smith. The effect of fertilizer treatments and dates of sampling on the easily soluble phosphorus in soil. Soil Science Society of America Proceedings, 11: 198-200. 1947. Reynolds, E. B. Yield and nitrogen content of legumes. Texas Station Progress Report 1204. 1949. Reynolds, E. B. and J. C. Smith. Effect of fertilizers and lime on emergence, nitrogen content, and ratio of roots to tops in hairy vetch. Agronomy Journal, 42: 387-389. 1950.