BULLETIN No. 120.API,10 APRIL, 1902 ALABAMA. Agricultural Experiment Station OF THE Agricultural and Mechanical College, AI B URN. THlE COW PEA AND THE VELVET BEAN AS FERIIZERS. By J. F. DUGGAR. MONTGOMERY, ALA.. 1HE BROWN PRINTING CO., PRINTERS ANI) IIINO)ERMS 1902. COMMITTEE OF TRUSTEES ON EXPERIMENT STATION. THOS. WILLIAMS....... ....... ..... .... .......... Wetumpka. Selma. JONATHAN HARALSON. ..................... STATION COUNCIL. 0. D. SMITH... ................................... Acting President. and Botanist. P. H. MELLL.....................................Director B. B. Ross...........................................Chemist. C. A. CARY, D. V. M...............................Veterinarian. J. F. DUGGAR. ........................................ Agriculturist. E. M. WILCOX........................Biologist and Horticulturist. J. T. ANDERSON..................................Associate Chemist. ASSISTANTS. C. L. HARE .......... ....................... First Assistant Chemist. Second Assistant Chemist. Assistant Chemist. Superintendent of Farm. T. BRAGG................................... J. C. PHELPS.................................Third T. R. U. W. CULVER................................. CLARK..................................Assistant Agriculturist. C. -F. AUSTIN................................ Assistant Horticulturist.. The Bulletins of this Station will be sent free to any citizen of the State on application to the Agricultural Experiment Station, Auburn, Alabama. THE COWPEA AND- THE VELVET BEAN AS FERTILIZERS. BY J. F. DUGGAR. Sununary. than fifty exThis bulletin records the results perinents conducted at Auburn during the past.five years, to ascertain.the effects of cowpeas and velvet beans in the. improvement't of the soil..The amount soil improvement has been determined by the increase in the yields of cotton, corn, oats, wheat and sorghum, grown as first, second, third or fourth crops after the stubble and roots of cowpeas or velvet beans or after vines, 'stubble and roots these plants have been plowed increase under. The basis for determining been the yield of each 'criop on plots where no leguminous plant has recently grown. scowThe fertilizing value of different varieties peas was found to vaty considerably, and is probably in of more of o'f this has of proportion to the luxuriance of growth. In. two tests there .was a slightly larger yield of corn from plowing in 'cowpea vines very late in the fall than from postponing the plowing until Ap'ril ; but it is regarded as, generally best to plow in the vines not more than a few weeks before the next 'crop is planted. The average for six varieties -showed that when lcowpeas were (at 'a suitable stage for mowing 36.6 per cent. an'd in another case 39 per cent. of the dry weight of the plant was available for fertilizing uses in stubble, root's 'and fallen leaves. In the entire growth of there wa~s contained in one case 53.7 peas on one another nitrogen, in another 69.8, and pounds nitrogen per acre, 87.2, 'an aver'age of 70.2 pound~s of acre cow- o'f in 124 which is equivalent to the nitrogen in 1,003 pounds of cotton seed meal. In the roots, stubble 'and fallen leaves on an 'acre there were, respectively, 11.65, 16.2 and 31.4 pounds of nitrogen, an average of 19.75 pounds of nitrogen per acre, which is equivalent to that contained in 282 pounds o'f 'cotton seed meal. The average of three tests 'shows that 28 per cent. of the total nitrogen was contained in the roots, stubble and fallen leaves after the removal of the hay. The average increase in the yields of succeeding crops was practically identical whether the fertilizing material was supplied by icowpeas or by velvet beans. Equal areas of these two plants were of practically equal value for :soil improvement. The word vines ins here used as synonymous with the entire plant of the velvet bean, and with the entire plant of the cowpea after the pods are picked. The increase in the yield o'f seed cotton produced in the year immediately following the plowing in of the vines of cowpe'as or velvet beans averaged in four tests 567 pounds per a'cre, worth (,at 6 cents per pound for lint and $7.50 per ton for seed) $14.17. The increase in the first 'cotton -'crop 'after the use as fertilizers of the vines of the summer legumes was never less than 32 per cent. and averaged 63 per cent. In one test with corn the increase in the first crop where velvet bean vines had been plowed in was 81 per cent., of 12.3 bushels, worth at least $6.15 per acre. With oats the 'average increase from the vines of the summer legumes in three tests 'averaged 17 bushels per acre, and with wheat the corresponding increase in two tests vas 5.65 bushels per acre. The increase in the yield of sorghum hay after cowpea and velvet bean vines averaged 87 per cent., or an 125 average gain of 2.1 tons of hay per acre, worth, at $6.67 per ton, $14.02. When the vines of the cowpea or velvet bean were utilized as hay and ,only the roots and stubble employed as fertilizer the increase in the yield per acre of the crop immediately succeelding the stubble was as follows: 208 pounds of seed cotton, or 18 per cent., worth $5.20. 4.3 bushels of corn, or 32 per cent.; 28 bushels of oats, or 334 per cent.; 6.7 bushels of wheat, or 215 per cent.; 2.08 tons of sorghum hay, or 57 per cent. The largest percentage increase from either the vines or stubble of cowpeas or velvet beans was made by wheat and fall isown oats, probably because these best prevented the washing away or leaching out of the fertilizing material in the stubble or vines of the legumes. Generally on sandy soil those crops most completely utilize the fertilizing value of the legumes which leave the land unoccupied for the shortest interval. It is generally unadvisable for legumes to immediately succeed legumes in the rotation 'o'f crops, for non-leguminous plants like cotton, ,corn, the small grains, grasses, etc., make better use of the nitrogen of the fertilizing crop. The value of the increased product resulting from the use of the entire legume for fertilizer was greater with cotton and sorghum than with corn, oats or wheat. These experiments emphasize the importance of such a rotation of crops as will require a large proportion of the cultivated land of every farm to be devoted to some leguminous plant. Comparing the fertilizing effect of the vines with that of the stubble of the cowpea and the velvet bean, the excess in the next crop in favor of the vines averaged as. follows: 126 6.6 bulshels of corn per acre, or.......... 49 per cent. .5 ton of sorghum hay, or ............... 9 per cent. 452 pounds of seed 'cotton per acre, or .... 40 per cent. With these 'three 'crops the average increase in value per acre was $5.98 greater from vines than from stubble. With oats and wheat the vines of these summer legumes were not superior to the lstubble when the small grains were sown immediately 'after the legumes m'atured. The fertilizing effect of the stubble of cowpeas or velvet beans was very transitory on sandy land, the average increase in the 'second crop of corn after the stubble being only 1.34 bushels per acre, or 12 per cent., as ,compared with the yield of a -plot that had not borne legumes. The fertilizing effect of the vines of cowpeas and velvet beans was less transitory than that of the stubble, land the increase was 24 to 54 per cent. in the second crop, 14 per cent. in the third crop (oats), and the favorable effect was even perceptible 'in the fourth crop (sorghum) grown in the same year as the third. The total increase in value of the four crops occupying certain plots during the three years after the plowing under of the vines of 'cowpeas and velvet beans was $42.97 per acre, an 'annual increase of $14.32 per acre. On the other hand, on very light soil the fertilizing effects of both stubble vines 'had practically disappeared within twelve months after the plowing in of the legumes. Corn as the second crop yielded 14 per cent., or 2.1 bushels more after legume vines than after legume stubble, this representing a value of $1.05. The permanency of effect of legumes in soil improvement seems to be in proportion to the 'stiffness of the 'soil ,and 'to the mass of vegetable matter afforded by the legume, and the favorable influence of leguminous vines is apparently not less permanent than that of stable manure. land 127 INTRODUCTORY. The improvement of the soil should be one of the chief aims of every farmer. Every increase in productiveness brings an even more marked increase in profits. Given rich 'soil, and almost 'any crop will pay if adapted to the local conditions and markets. Labor spent in the 'cultivation of corn or cotton on extremely poor soil usually earns scant reward or none. Fortunately much of the poorest worn land can be brought to a fair degree of productiveness. The means of soil improvement are various. Most thoroughly tested by long experience in Europe and America is that 'system of f'ar'ming which depends for soil enrichment on the manure from a large number of livestock maintained on the 'farm, partly for immediate profit, but largely for use as manufacturers of fertilizers. This system should be much more generally followed in Alabama.: However, its introduction will be gradual because of limited capital, inexperience, and the ,small number and poor quality of the native livestock that must serve as a foundation for stock raising. Meantime the most immediately available method of increasing the fertility o'f the soils of the South consists in the free use of that class of leguminous plants, or legumes, which embraces cowpeas, velvet beans, soy beans, beggar weed, peanuts, hairy vetch, crimson clover, and numerous others. When these plant's 'are grown under suitable conditions specific enlargements occur on their roots and these are called root tubercles, or, root nodules. The microscopic organisms which live within these tubercles are able to assimilate the nitrogen of the air that circuthrough the upper layers o'f the soil. This nitrogen while a part of the 'air was useless to plant life, but lates 128 within the tubercies it is changed into available fertilizer and is carried by the sap to every part of the legnminons plant. Hence we may speak of these tubercles as fertilizer factories where nitrogenons fertilizers are mannufactnred and -whence they sent to every part of the cowpea velvet bean, or other-legnminons plant. The plowing in of the legume gives this nitrogen to the s:oil for the nse of other plants. Nitrogen.when of 'cotton'seed 'meal 'costs 12 to purchased in the 15 cents per pound, but when it is furnished legumes principal outlay being for it is -many tires cheaper, the seed and labor. Great as is the need of the South for varied indnstrial development, the factories most urgently needed and paying l'argest dividends are those which every farmer can bring into 'being by the million the roots of snch legumesa's cowpeas, velvet beans, vetch, crimson clover, nielilotus, b'nr clover,'and 'alfalfa. These crop's afford nitrogen and vegetable matter, thns snp'plying the principal deficiencies of sothern soils, an'd they may be either nsed directly and exwith greater profit the lusively for this purpose, tops may first 'fed to livestock, thns affording 'a twofold profit in animal prodncts and fertilizer, while the stubble and roots are immediately ' ivail'ab'le 'fo'r soil im- .or are for~rm by on be or provement. 'The 'stubble alone usually causes !a sufficient in'crease pay the 'following crop to more of seed, fertilizer, and cultivation of the legnme, co'st a net gain. leaving the food valne of the tops The principal part of this bniletin is 'ocnupied with d'ata obtained at A'bnrn 'dnringthe past five years and bearing on the extent arnd permianency 'of the fertilizing 'cowpeas an'd velvet beans. effect The following 'conditions prevailed in all of these tests, unless otherwise specifically stated : in the yield of 'the than as of 129 The legumes. were grown, in drills and cultivated and moderately fertilized with acid phosphate or with phosphate and some potash salt. The crops, corn, cotton, oats, wheat, sorghum, and rye, used to measure the fertilizing effects of the legumes, have received no application of nitrogen, but have been fertilized with phosphate and potash. The soil in all tests is rather poor to extremely poor deep sandy upland, t'he white or gray being almost 'a pure Isand and the reddish soil approaching a loam with clayey loam subsoil in the latter case. stubble of the legumes have been plowed The vines under just before the planting of the next crop. The variety of ceowpeas employed was the Wonderful or Unknown. In valuing the crops the endelavor has been made to use conservative 'average price's, the error, if 'any, being in putting them too low rather than too high. Lint cotton hass been rated at 64 'cents per pound, cotton seed at $7.50 per ton, sorghum hay 'at $6.67 per ton, corn at 50 cents, oats 40 cents, and wheat 80 cents per bushel. No record is here made of the increase in the yields of grain, straw or corn stover, assmuing that this has been about sufficient to cover the increased cost of harvesting and threshing. .or TIME TO PLOW IN COWPEA VINES. On a gray sandy upland soil the vines of drilled cowpeas were plowed under in the late fall o'f 1898 and 1900, while on other plots plowing was deferred until nearly planting time. The yields of corn were as follows: 130 Iushels of corn per acre following cowpea vines plowed under in late fall or early spring. 11899 23.8 Bus. per acre. (1901 IAv. 2yr. 30.6 27.2 Fall plowed.................. Spring plowed........................20.8 Difference.............3.0 29.7 0.9 25.3 1.9 The results are slightly in favor of plowing under peavines in the latter part of the fall rather than in spring. As the plots were not strictly uniform, further experiment's are needed 'before definite conclusions can It 'should be said that on July 5, 1899, the be daw. foliage of the corn plant was much greener where the vines had been turned under in the fall than on the other plots, though -the ears were not discernably different. It is usually rega'rded as 'best to'avoid fall plowing on sandy land in the South unless a winter cropis to be grown. On heavy soils whereifall plowing may otherwise be desirable, the legumes should first be allowed to mature. Unless otherwise stated the time of plowing under coxvpea and velvet bean vines referred to in this bulletin is 'a few days or weeks -before the planting of the new crop that is to occupy the ground. RELATIVE FERTILIZING_ VALUES OF COWPEAS, OF DIFFERENT VARIETIES cowpeas 'Corn was grown in 1898 and 1901 immediately foblowing different varieties. of 'drilled which had been picked and in spring the vines plowed under. 131 Excess of yield of corn in bushels per acre on vine plots tpared in 1898 with ivo-legumes plot and in as corn 1901 with plot where only pea stubble had been plowed under. Variety ot cowpeas Wonderful (or Unknown)................2.7 Whippoorwill.......... ............... Clay.........4.3 Black, from Hastings...............-2.9 Red Ripper...............................5.9 New Era ....... ....White Giant..............................0.6 Jones White ................ Large White Crowder.....................5.3 Lady........6.8 Average 1 1898. Bus I 1901. 0.6 Bus. -1.5 0.7 3.2 1.9 2.9 3.3 1.4 These figures are given merely as a matter of record, and no ,conclusions are yet warranted..A's.a.matter of common experience any Variety of cowpeas affords in its vines as much or more nitrogen than the following corn crop can utilize. For crops requiring a larger amount of nitrogen or for larger supplies of vegetable matter we may safely value the numerous varieties of cowpeas in proportion to the yeil'd of hay which- they would afford if thus utilized. As noted in Bulletin 118 Wonderful (or Unknown), Clay, and Iron are among the. varieties making large yields of hay, and hence of by reason of its fertilizing material. The large yeild, large 'stems and roots, and varied usefulness, i's especially riecommen'ded for fertilizing purposes. It is possible, however, that future investigations may show some advantage for varieties, that. run along the ground and thus 'by the itangle of runners hold in place on 6loping ground in winter 'a larger proportion of .the leaves than is d'one 'by an erect :variety like Wonderful, -Whippoorwill. or. Wonderful. 1632 COwiPE VINES, EFFECT ON FOLLOWING COTTON CROP OF 1899. On a reddish loam upland ,soil of fair quality drilled Wonderful Fcowpeas and cotton, ,similarly fertilized were grown in 1898. The peais were picked, yielding 11.8 bushels, per acre, and the vines were plowed under the next spring, when both areas were planted ton. The corrected yield of cotton in 1899 was 367 pounds, or 32 per cent. greater on the area where the peavines had been plowed in than on the plots where the preceding crop had been cotton. Coopea vines, residual fertilizing effect on second crop, viz., oats grown in 1900.-Burt oats were sown in February, 1900, on the same plots as above to test the residual or 'second-year effects of cowpea vines. On some plots the oatsi received no nitrogenous fertilizer, on others 76.ppounds of nitrate of soda was used per acre. The yields of oats, in bushels per'acre, were as follows : with-cot- Fertilizing effects on oats of cowpeas grown two years before. After cotton in '98 and '99 Bus. 19.7 I Yield of oats per acre withinitrate of After cowpeas in Increase attribu'98 & cotton able to cowpeas of '98. in '99. Bus. I Bus. % 25.5 5.8 29 Yield of oats per acre without nitrogenous fertilizer............. soda. . 12.3 22.0 9.7 79 In this ,case 'we have an increase of 9.7 bushels, or 79 per cent, as the effect of 1cowpea vines on oats grown as the second crop after 'cowpeas. So strong was this 133 fertilizing effect of cowpeas that it was not entirely obiscured even when ni'tr'ate of soda was also employed, the increase in the yield of oats under these conditions being 29 per cent. Cowpeas as fertilizer on. lime land.-A co-operative fertilizer experiment w'as conducted for this Station by Capt. A. A. McGregor on lime land at Town Creek, in North Alabama. In his experiment the cowpea was the legume employed. In 1898 cowpeas were grown on certain plots and cotton on others. The 'cowpea vines, on which no fruit had matured, were plowed under in the spring of 1899. Cotton was planted on plots which had borne a crop of cotton in 1898 and on others which had grown cowpeas for 'fertilizing purposes. All cotton plots referred to in this paragraph were unfertilized in 1899, and the fertilization of cow.peas and cotton in 1898 had been identical, only phosphate having been used with either crop. The weather was exceedingly unfavorable in 1899, so that the full measure of the fertilizing value of cowpeas was not revealed in this test. In this case the .average increase in the yield of seed cotton, which we may attribute to the co'wpea vines is, even under very adverse conditions, 58 per cent., or 125 pounds, worth at 21 cents per pound, $3.92 per acre. Doubtless later crops have 'also been benefited by the fertilization with cowpeas. There is reason to expect a larger increase than the above when cowpeas are plowed under on the lime lands of either the Tennessee Valley or of the Central Prairie Region of Alabama. Especially in the prairie soils the principal need is for vegetable matter to lighten the soil and to add nitrogen, and for these purposes the choice must usually be made between melilotus (the so-called lucern) and cowpeas. 134 FERTILIZING EFFECTS OF VINES OF COWPEAS AND VELVET BEANS AS SHOWN BY SORGHUM IN 1897. In 1897 sorghum was grown on three plots following, respectively, velvet bean vines plowed under, cowpea vines plowed .under, ,and fallow, or clean cultivation without crop in 1896. In 1897 the yields of sorghum hay per acre were as follows: Yield. Lbs. I 3,792 7,008 7,064 Increase Lbs. % 3,216 3,272 85 86 After fallow ........................ After cowpeas, plowed in ............. After velvet beans, plowed in .......... The effect of the legumes was to nearly double the crop of sorghum hay. FERTILIZING MATERIALS IN LEAVES, STEMS, AND ROOTS OF THE COWPEA. In September, 1899, just 81 days after the planting of the seed, samples were taken ,of six varieties of cowpeas growing in 34-inch drills on poor gray sandy land. The sample in each case comprised the entire growth on a measured area of land, including the roots growing in the upper 6 inches of soil, which stratum contained nearly all the roots. After curing, the leaves, blooms and pods, coarse stems ,fine stem's (including runners, leafstalks, etc.), fallen leaves and leafstalk ,and roots with attached stubble about two inches long, were 'carefully separated. Analyses were made in the chemical department of a composite sample representing all six varieties, the material analyzed being extremely dry. (For analysis of same 'samples showing food value see Alabama Station Bulletin No. 118, page 37.) 135 The following table shows what percentage of the total air-dry weight of the plants of each variety was available for fertilizing purposes after the removal of the hay. Per cent. of the entire weight of the eowpea plant in stubble and roots and in fallen leaves and leaf stalks. Fallen Variety, Miller..................7.7 Whippoorwili....................3.7 Iron .......................... W\onderful ............ ........ Jones White ................... Clay .. .. ... .. Average, 6 varieties ........... I leaves, etc. Roots and 2-inch stubble. 25.0 21.6 19.0 20.3 14.5 26.0 21.1 Total. 42.7 25.3 34.4 39.5 28.8 48.9 .... 15.4 19.2 14.3 22.9 11.5 36.6 'The -average for the six varieties'show's that in each pounds of dry plants there were 15.5 pounds of fallen leaves and leaf stalks, and 21.1 pounds roots and stubble, making a 'total 'of 36.6 pounds, more than one-thir'd of the entire plant being'thus left on the ground for fertilizer after the hay was cut. 100 of Analyses of the different parts of the plant made by Prof. C. L. Hare, of the chemical department o'f this station, are recorded in the following table. Comtposition of parts of the air-dry eowpea. plant. Phosp'ric .78 .64 .42 .37 .26 Water. 'Nitrogen. Leaves........ ........... 10.65 Fine stems.........8.97 Coarse stems.............. 8.47 Fallen leaves and leaf stalk-9.75 Roots and 2-inch I1% IAcid. I1 IPotash. %% 1.49 .68 1.49 1.09 1.11 stubble. . 3.59 1.90 1.51 1.67 1.38 5.25 is the only one of the three p'recious elements that the Let us direct our attention to the nitrogen, since this plant obtains (in part) 'from the air, and 'the only one in 136 which the soil is enriched by the growing of 'cowpeas. The growing leaves in the airdry condition contain ne'airly twice as large a percentage of nitrogen as the fine stems, and more than twice as much as the coarse stein's and roots and fallen material. 4nto ants of air-dry material and nitrogen afforded by IAir dry material. Lbs. different parts of the cowpea plant on one acre (average lof six varieties) I In In In In In In leaves retained on vines..................501.0 fine stems...................01.6 coarse stems...................38.8 pods,'blooms, etc ......................... fallen leaves and leaf stalks ............. roots and 2-inch stubble ................. Nitrogen. Lbs. 18.00 7.66 6.61 *9*75 325.0 357.3 411.7 5.97 5.tb 53.67 Total..................................2435.4 *Assuming 3% of nitrogen in thoroughly air-dry pods. The amount of nitrogen stored up by a poor crop of an 'acre, 53.67 pounds, is equivalent cowpeas growing 'cotton seed meal. It that -contained in 767 pounds should be remembered that an undetermined portion of to on o'f though on a 'soil as this nitrogen came from poor as this the nitrogen derived from the pair probably the soil, constituted by far the larger portion of the total nitrogen utilized 'by the -plant. In the stubble, roo'ts, 'and fallen umaterial there was 11.65 pounds of nitrogen per acre or the 'same amount as is 'contained in 162 pound's Of the total nitrogen in the entire plant 22 per cent. was found in tile roots, 'stubble and 'fallen material. An experiment 'somewhat similar to the preceding made in 19003, using only a single variety, Wonderful. or Unknown. The. seed were planted in drills 2~ was of' cotton seed meal. 137 feet apart on p-ooi gray sandy soil. Four samples were taken from two plots, each sample consisting of the entire growth on an .area of four square yards; the roots w Tere obtained by digging and sifting the soil to a depth of six inches, to which sr-tnra all the principal roots werc apparently confined. That the samrples we're accurately'htken is indicated by the close agreement of the duplicate samples; hence only 'average results are given below. The vineswere cut, the fallen leaves and leaf stalks collected; and the roots sifted ,olut on September 5. This was 106 days after after plantthe date of planting on one plot and 78 ing on the other. slightly When harvested the more mature sample pas't its prime for hay, as shown by the unduly large amount of fallen leaves, while the other sample was too immature 'and succulent for easy curing. The yields per acre of extremely dry hay according te the weight of the taken after being stored in an were 2,269 pound's on the plot office for seven cut at a late stage, and 2,087 pounds of less mature material. These are equivalent to about 1 . and 1 s tons per 'acre of hay with the u'ual amount ,of moisture. days was months, samples the cowpea Weights- (air-dry) per acre of hay, and fallen leaves of the roots, and stubble, cowpea.. Air dry material, per acre. Ripening Blooming stage. stage. Lbs. Lbs. 2,087 Vines, including stems, leaves, pods, etc 2,269 Roots, and stubble about 2 in. long. 714 502 Fallen leaves and leaf stalks .... 1,385 804 Total.................................4,368 3,393 138 The following table sihows what proportion of the en- tire plant consisted of roots, fallen material, and hay, in the plants harvested when ripening or when in bloom. Ripening stage. Tops....................................52 Roots and stubble.........................16 Fallen leaves, etc ........................... IBlooming 1stage. 61 15 32 24 hay was made of cowpeas past their pie there was left on the ground in roots, stubble, and fallen material 48 per cent. of the weight of the plant, and When mowing occurred when the vines were in bloom 39 per cent. of the total weight remained as fertilizer material. When Analyses made by Prof. J. T. Anderson, Associate Chemist of this Station, are recorded below: Composition of hay, fallen nmaterial, and roots and stubble of the eowpea. In ripening Hay........ ........ Fallen leaves and leaf stalks.......... Roots and stubble .. Inbomn .... stage: IWater. %I Nitrogen. IAcid. 1 Potash. 9.05 7.80 7.77 2.46 1.83 1.17 2.57 .85 .64 .48 .81 2.14 1.45 1.51 2.86 ............. tg:Hay .. .. Fallen leaves, etc. Roots and stubble 58.15 6.80 7.00 1.36 1.05 .59 .41 1.15 2.11 From this table it may be 'that the hay is more than twvice as rich the roots and 'stubble in nitrogen, as seen and also richer in phosphoric potash. The amounts of nitrogen contained in the hay, 'fallen acid and material, 'and roots and stubble on one acre were as follows: 139 Ripening stage. Lbs. nitrogen. In hay.......................... In fallen leaves, etc............... In roots and stubble ................. Total per acre ................... 5.8 23.1 .8.3 87.2 Blooming stage. Lbs. nitrogen. 53.6 10.9 5.3 69.8 The total amounts of nitrogen stored up by the pea plant on one acre was in one case 87.2 pounds, in the other 69.8 pounds, equuivalent, respectively, to the nitrogen in 1,246 997 pounds of cotton seed meal. Of this amount there was left in and on the soil when cow- and mowing occurred late 31.4 pounds of nitrogen; and from the younger plant's 16.2 pounds per acre. This is equivalent to the statement that the nitrogen per acre remaining 'after the vines were removed wasequal to the amount contained in 446 or 231 pounds of cotton seed meal. Of tile total nitrogen in the plant, the roots, stubble, and fallen material containe'd 34 per cent. at the ripening stage, and 23 per cent. at the blooming period. Considering the three tests together the total amounts of nitrogen per acre of was 70.2 pounds in the entire growth, stubble was 19.75 pounds, or 28 per cent. COWPEA STUBBLE VERSUS 'COWPEA VINES AS FERTILIZER FOR CORN IN .of cowpea's which the average amount in the 1901. 'Corn wa's grown in 1901 on 'sandy loam land, which, in 1900 had borne light crop of 'drilled cowpeas, planted after the removal of the oat 'crop of 1900. Three plots 'were employed. On one the peavines had been cut the previous September, yielding 1,648 pounds of h'ay per acre. On the other two plots no vines nor peas were harvested 'but the entire growth, which was a 140 only about half of a normal yield, was plowed under Msarch 14, at which time the stubble plot was also plowed. On the stubble plot and on one of the others corn was fertilized with 100 pounds of acid phosphate per acre, which fertilizer was omitted from the third plot. The stand was uni'form. The yields of corn in bushels per acre were as follows: Bus. Pea stubble and phosphate as fertilizer ................. Pea vines and phosphate as fertilizer ................... 11.40 20.28 Pea vines as fertilizer, no phosphate .................... 21.74 The yield of corn following pea vines was 78 per cent. greater than the yield on the plot where the stubble only had been plowed under, the increase being 8.88 bushels per acre. In the presence of a considerable amount of rich vegetable matter furnished by pea vines, phosphate was not needed on this soil where acid phosphate had been applied annually for many years. In a different field on more permeable gray sandy soil corn grown in 1901 on a plot where the stubble of Wonderful cowpeas had been plowed under for hay The average yield of yielded 25.3 bushels per acre. corn on two 'adjacent plots-where cowpea vines of the varieties Lady and White Giant, both luxuriant growers, had been plowed under, was 25.9 bushels per acre. Here there was practically no superiority of vines over stubble as a fertilizer for corn. Note should also be taken of the increase in the corn crop due to plowing in either stubble or vines of a number of varieties as recorded in the table on page 131. 141 VELVET BEAN STUBBLE AND VINES AS FERTILIZERS FOR CORN IN 1901. The fertilizing effect of velvet bean stubble, of velvet bean vines, and of velvet bean vines in connection with acid phosphate, was tested in 1901 on four plots of very On one plot the procedpoor, deep whitesandy soil. ing crop had been corn. On the other three plots drilled velvet beans planted June 13, after the harvesting of the oat crop, had made only a moderate growth in 1900. On one of these plots the velvet 'bean vines were cut September 10, 1900, yielding 3,632 pounds of hay per acre. On the other two plots the vines were left on the land all winter. In the latter part of the winter all four plots were plowed, a disc harrow having first been run over the field while the vines were frozen in order to cut them and thus render it easier to plow them in. 'The corn on three of the plots was fertilized with 100 pounds of :acid phosphate per acre, but this fertilizer was omitted on one of the plots where velvet bean vines had been plowed in. Yield of corn in 1901 following corn, velvet bean stubble, or velvet bean vines. Bus. Phosphate (but no legume), as fertilizer...... 13.58 Velvet bean stubble and phosphate as fertilizer.. 17.93 Velvet bean vines and phosphate as fertilizer... 25.90 Velvet bean vines (no phosphate), as fertilizer.. 21.48 The increased yield per acre, as compared with the yield on the plot on which the previous crop had been corn, was 4.35 bushels, or 32 per cent., with velvet bean stubble, and 12.32 bushels, or 81 per cent., with velvet bean vines. 142 The increase attributable to 100 pounds of acid phosphate was 4.42 bushels, which made the use of this mineral fertilizer decidedly profitable for corn on very poor white sandy soil, when used in connection with a large mass of ,rich vegetable matter. On the other hand, on a spot about 100 yards distant, where the soil was less sandy ,and in better condition, phosphate did not increase the yield of corn when added to pea vines plowed under. (See page 140.) IMMEDIATE FERTILIZING EFFECT ON SORGHUM OF COWPEA AND VELVET BEAN VINES AND OF COWPEA VELVET BEAN STUBBLE. AND 'The soil on which the following experiment was made is a sandy loam, containing many small flint stones, and underlaid by a stiffer isubsoil. In 1898 eight uniform plots were planted, 2 plots with velvet beans, 5 with Wonderful c'owpeas (most plots broadcast), and 1 with drilled Orange sorghum. The growth 'of the several plots was either cured for hay or used as a fertilizer, as indicated in the next table. March 9, 1899, all plots were plowed and in due time sorghum was planted in drills on all plots, and the two cuttings of this crop at the proper season were cured for hay. The yields per acre of sorghum hay at two cuttings, the first growth having become too coarse, but the seeond being of good quality, averaged as follow's: First year effects on sorgh-um of stubble or vines of cowpeas or velvet beans. Yield per acre. Tons. 3.65 5.66 5.80 5.72 6.76 Increase from legumes. Tons. 2.01 2.15 2.07 3.11 Sorghum Sorghum Sorghum Sorghum Sorghum hay after sorghum stubble.. hay after cowpea stubble.. hay after velvet bean stubble hay after cowpea vine, pckd hay after velvet bean vines 143 As a fertilizer for sorghum velvet bean vines proved superior to cowpea vines, and to velvet bean stubble. of The stubble co'wpe'as and of velvet beans practically equal fertilizing value. ,of was Residual fertilizing effect of legumes on corn grown as the second crop after cowpea, and velvet bean vines and cowpea and velvet bean stubble. March 17, 1900, the sorghum stubble in the.experiment just discussed was turned with a onerhorse plow and March 29 corn was planted on all plots. "Fertilizing effects in 1900 'of stubble and vines peas and velvet beans grown in 1898. of cow- Corn per acre in 1900. Plot. Crop in 1898. Portion used for fertilizer. Increase Increase, over sorgvines Yil"hum plot over _________________of 1898. Bus. 5 ISorghum .. tubble ............ 241.......... & 6 Cowpeas 8 4&7 Cowpeas m ... .Vines,b after 3 ... Co p . S rh atu tubble......... picking . tu be..2 e... 27.7 241.&7 .. 2 Velvet stubble. Bus. Bus. 1.6 3.062.0 1 Velvet btans. Entire growth ... beams. Stubble........... 23.9 26.8 0.2 ...... . 2.6. Let it be noted that the heavy growth of sorghum in 1899 did not utilize 'all of the fertility derived from- the preceding crop of legumes. Although 'sorghum is: a plant that i's especially exhaustive to soil fertility, there still remained for the 'corn crop of 1900 a residue nitrogen from the c'owpea and velvet 'bean vine's, of 1893 sufficient to increase the yield of 'corn to the extent of 3.6 bushels per acre where -cowpeas had 'grown two years before, and 2.6 bushels w~here velvet beans had grown. Thi's is of an average 'o'f 3.2 bushel's per acre as, the residual fer- tilizing effect of these legunmes. 144 The fertilizing effects of the stubble these two plants was far more and transitory, the roots of suc- first ceeding -crop, sorghum, practically exhausting them, leaiving in the soil to increase the corn crop of 1900 by only an inconsiderable amount, viz.: 1.6 bushels and .2 bushel, an average of .9 bushel per acre." (From Bulletin No. 111, Alabama Experiment siufficient Station.) IMMEDIATE FERTILIING OF COWPEA AND EFFECT VELVET ON a CORN IN 1900 BEAN VINES. white, sandy soil, This experiment was made on poorer than that used in the last mentioned experiment. In the late spring and early summer of 1899 velvet beans had been planted in drills on certain plots begweed head been sown broadcast onothers. gar weed and a portion of the velvet beans was used exclusively for fertilizer. On other plots velvet beans fertilizer for were cut, thus leaving only the stubble corn. "These various fertilizing materials were all plowed begga r The and as under M'arch 31, 1900, and Mosby corn planted April 'and 40 5, using per acre 240 pounds of pounds 'of muriate acid phosphate of potash. Y Ines versus stubble of velvet b~eans as fertilizer for Jncrease over stubble plot. Bus. 11.9 3.1 corn in 1900. Plots . Material used for green manuring, Yield of corn per acre. .Lus. 15.6 27.5 18.7 4 & 9 3 &8 2 &7 Stubble of velvet beans................ Entire growth of velvet beans.......... Entire growth of beggar weeds......... 145 The entire growth of velvet beans afforded a yield of corn greater by 11.9 bushels per acre, or 76 per cent., than the yield where only the!stnbble was employed as fertilizer." (Alabala Station Bulletin No. 111.) Residual fertilizing effects of velvet bean vines and stubble on the second crop of corn grown in 1901. The same poor,, white, 'sandy hilltop was again planted in corn in 1901 withont any nitrogen'The yield of corn per acre were 15 ous 'fertilizer. where velvet bean vines growing in 1899 had bnushels been plowed under and only 11.1 bushels where velvet bean stubble had been turned nnder at the same time. The residnal or isecond-year fertilizing effect of the vines was greater than that 'of the stubble by 3.9 bushels per a-cre, or 33 per cent. The total fertilizing value of the vines during the sea-sons following the date 'when they were plowed in the exceeded that eoaf stubble to the extent of 59 per cent., of corn 15.8 bushels off corn per acre. This would usually be worth more than the net value of the 2,809. pounds velvet bean hay obtained from the stubble plot at considerable expense for curing. two or affint of vet bean- ines 1n this case it was more profitable 'to plow under vel- bay. from other corresponding tests it would have been still more profitable to 'have grazed cattle on the vines, either in their green or' winter-killed condition. Judging for fertilizer than to harvest them for COWPEA AND VELVET BEAN VIN ING EF FECTS ON ES, IMMEDIATE FERTILIz1899. COTTON GROWN IN In 1898 on 'a reddish loam 'soil, abounding in flint stones 'and underlaid by a -red loam 'subsoil there were grow n on adjacent 'plots -coxvpeas, velvet bean's, and 'cot- 146 ton, all fertilized alike with acid phosphate and kainit. The cowpeas and velvet beans were planted thickly in drills, using per acre 112 pounds of cowpe'as and 120 pounds of velvet beans. The variety of cowpeas used was the Unknown or Wonderful. Both cowpeas and velvet beans were piicked and removed from the field, though the latter did not fully mature. The vines were turned under in March, 1899, and all plots were planted to cotton; each plot of cotton was fertilized at the rate of 240 pounds of acid phosphate and 96 pounds of kainit per acre. The yield of sleed cotton per acre in 1899 was 1,533 pounds following cowpeas, 1,373 pounds following velvet beans, 'and 837 pounds following cotton. These figures show that the increased yield of seed cotton 'attributable to manuring with cowpea vines was 696 pounds per acre; the gain apparently due to the fertilization with velvet beans was 546 pounds per acre. In percentages the increase is 83 and 64 per cent., respectively. Valuing seed cotton at 22 cents per pound (which is equivalent to 64 cents per pound of lint and $7.50 per ton of seed), the gain with cowpeas and velvet beans is worth, respectively, $17.40 and $13.65 per acre. Surely it was 'more profitable to grow cotton every alternate year at the rate of a bale per acre than to grow continuous cotton crops of about one-half bale per acere. Additional proof of this is found in the fact that one of these plots afforded in 1898 a yield of 18- bushels of cowpeas per acre, besides increasing the cotton crop of the following year to the extent of $17.40 per acre. 147 Residual fertilizing effects of cowpeas and velvet beans on sorghum, oats, and late sorghum grown as second, third and fourth crops after legumes. these These same plots were planted with drilled sorghum with without any nitrogenous fertilizer in April, 1909; red oats without nitrogenous fertilizer in November, 1900, and again with drilled sorghum without any nitrogenous fertilizers, July 18, 1901. Fertilizing effects of cowpeas and velvet bean vines grown in 1898 on sorghum in 1900 and as a second crop in 1901. Sorghum hay per acre, 1900. Tons. 5.1 8.1 8.2 Sorghum hay per acre, 1901. Tons. 1.0 1.5 1.6 Total increase after legumes. Tons. 3.5 3.7 Preceding crop, Cotton in '98 and '99............ Cowpeas in '98 (picked), and cotton in '99 ................. Velvet beans in '98, and cotton in '99 .. . . . ... . . .. As compared with the plot not recently in legumes the increase of sorghum hay per acre in 1909 from coawpeas grown two years before was 3 tons per acre, or 59 per cent. ; from velvet two years before the increase in 1900 3.1 tons ,of hay, or 61 per cent. wa's beans The increased yield with late 'sorghum, which was the fourth crop after tile plowing in 'of the vines of the legumes, was, after cowpeas, .5 a ton, and af ter velvet beau .6 of ton. In the two sorghum crops the total 'increa~se in yield 'attributable to legumes was, with cowpeas, 3.5 tons hay, and with velvet beans 3.7 tons of sorghum per acre. a of of 148 Now let us go back a few months and note the yield of the oat crop coming between the sorghum 'crops of l900 and 1901. Yield of oats in 1901 grown as the third crop after legumefls. Yie sIncrease Preceding crops: Cotton in '98; cotton in '99; sorghum in 1900 Cowpeas in '98; do do Velvet beans in '98; do do YielJoats per acre. after legumes. Bus. 23.3 26.5 37.2 IBus. 00o 13.91 3.21 14 59 The fertilizing effect 'of the legumes in the third :crop after tie legumes, the increase where cow,-peas had once grown being 3.2 bushels of oats per acre, or 14 per The increase where velvet beans had been is suspiciously large, and in subsequent calcu= la.tions it will be a~su'med that the increase in the yield wasapparent cent. on would 'have this plot if not influenced by !accidental 'conditions been no greater than 'that on the plot once in cowpeas, viz., 3.2 bushels per acre. Financial results of using cowpea vines as fertilizers for cotton, sorghumn, oats, and late sorghuam. Let ns convert these yields of cowpeas, cotton, sorghum, and oats into their money values to learn whether the introduction cowpeas or velvet 'beans into the rotation has been profitable. of 1 V lie 9 a of crops per acre in three years (1) following cotton and (2) following cowpea vines. (18 Value of crops per acre in 99. 1900. 1901. Total for 4crops Jin 3 years. Plot 3-No legumre in 5 In '99, 837 lbs. seed cotton, at 2l/c* $20.92 In '00, 5.1 tons sorghum hay, at years: I In 1901, 23.3 bus. oats, at 40c... In 1901, 1 ton sorghum hay.. $6.67 per ton.............. $33.02 $9.32 $6.67 $69.93 Plot 1, cowpeas in '98, picked and vines plowed under: In '99, 1,533 lbs. seed cotton at $38.30 212 c .......................... In 1900, 8.1 tons sorghum hay.... $54.00 $112.90 In 1901, 26.5 bus. oats, at 40c.... $10.60 1 In 1901, 1.5 tons sorghum hay .... 1$10.00 Diference in 3 years.............. I Average difference per year peracre(I($14.32 I $42.97 *Equal to 6 3/ cents per pound of lint, and $7.50 per ton of seed. The-total value of the products grown in three years on an acre was $69.93 on the plot no legume had been grown for -many years and $112.90 per acreon the plot where one crop of cowpeas had been grown once where in four year's, and where the vines, after the the peas, had been plowed under at the beginning of the had been grown -pcigof three-year period under consideration. The difference in the value of the crops for three years is $42.97; the average annual difference is $14.32 per acre in favor of the plot ,where cowpeas The figures showing the financial advantages 1of using one crop of velvet beans for 'fertilizer during the same period so nearly correspond with those for cowpeas that the calculation need not be repeated. On this land the plowing under of the vines of the cowpeas and velvet beans was exceedingly profitable. The 150 soil of these plots is a reddish, clayey loam, stiffer and probably more retentive of fertilizer nitrogen and humus than the greater portion of the soil on the Station Farm. Lest any should misapprehend the lessons of this experiment it is necessary to state that at no time in the three-year period was any nitrogenous fertilizer applied to any crop on any of these plots, but that each crop was supplied with phosphate and potash. The yearly application of cotton seed meal would have lessened the differences between the plots, as it has done in our unpublished rotation experiments, and would have m'ade the advantage in favor of legumes less 'striking than in the exhibit above. IMMEDIATE FERTILIZING EFFECTS ON COTTON OF VELVET BEAN VINES. On poor soil at Auburn an effort was made in 1898 and 1899 to 'ascertain the manurial value of the vines and stubble of velvet beans. In 1898 cotton was grown on certain plots and velvet beans on others. The fertilization of all plots in 1898 was not identical, but for a given fertilizer applied to cotton there was ,a plot of velvet beans receiving the same fertilizer. The velvet beans grew in drills 3 feet apart; the vines formed a dense mat of vegetation, but did not mature seed. In March, 1899, velvet beans and cotton stalks were plowed in and soon afterwards all plots were fertilized alike with a mixture of 240 pounds of 'acid phosphate and 40 pounds of muriate of potash per acre. Russell cotton was planted in 3 feet drills on all plots on April 21. From midsummer forward there was a remarkable difference in the appearance of the two 151 sets of plots, the cotton plants being much larger, greener, and more luxuriant on the plots where velvet beans had grown the year before. Av. yield of seed cotton per'acre following velvet bean vines......................1,578 lbs. Av. yield of seed cotton per ,acre-following cotton..............................918 lbs. Increase from velvet bean vines........660 lbs. The average increase 'attributable to velvet beans used as a fertilizer was 660 pounds of seed cotton acre, a gain of per cent. as compared with the average yield on plots where the preceding crop had been cotton. At 2z cents per.pound of 'seed cotton (equivalent to 6g cents per pound for lint and $7.50 per ton for this increase is worth $16.50 per acre. 72 per seed) Residual fertilizing effects oa corn vinzes. of velvet bean ,The residual ,or second-year, effects were tested on corn planted on these plots March.29, 1900, without nitrogenous fertilizer. Where cotton had grown in 1898 the yield of corn in 1900 wa's 18 bushels, per acre; on the next plot, where velvet beans had been grown for fertilizer in 1898, the yield of corn in 1900 wa's 25.5 bushels. This gain of 7.5 bushels per acre, or 42 per cent., represents the residual or 'second-year effect of using the growth of as a fertilizer. velvet beans entire .IMMEDIATE AND RIESIDUAL EFFECTS OF VELVET BEAN STUBBLE ON COTTON AND 'CORN. field the velvet beans on one plot were The stubble roots In the same cut for hay October 12, 1898. ,and 152 were plowed in at the same time as the vines on the other plots referred to above. Clotton on the plot where only roots and stubble were plowed in yielded in 1899 1,126 pounds of seed cotton per acre, an increase when compared with the plots where cotton had grown the previous year of 208 pounds, o'r 49 per cent. Comparing velvet bean vines with velvet bean stubble the difference in favolr of the vines was 452 pounds of seeld cotton per acre in the first crop. Corn in 1900 on this plot yielded 14 per cent., or 2.6 bushels per acre more than did corn on the nearest plot where in 1898 cotton instead of velvet beans had grown. As the stubble plot was slightly lower down on the hillside we suspect that the increase was partly due to this disturbing condition and not wholly to the residual effects of the velvet bean stubble of 1898. It was on this stubble plot that in 1898 the velvet bean hay (8,240 pounds per acre) contained 188.7 pounds of nitrogen and the roots and stubble and fallen leaves only 12.5 pounds of nitrogen per acre. (See Alabama Station Bulletin, No. 104, page 336.) IMMEDIATE FERTILIZING EFFECTS OF COWPEAS ON OATS IN 1897. "On sandy soil in 1896 several plots were sown broadcast with the Wonderful variety of cowpeas, and an adjacent plot was sown broadcast with German millet. The millet was plowed under, as were also the peavines, the peas having been previously picked. February 18, 1897, Red Rust Proof oats were sown after the above mentioned crops, using in both cases 100 pounds of acid phosphate and 80 pounds of nitrate of soda per acre. German 153 After cowpeas the oat straw grew to be three to four inches taller than on the plot preceded by German millet. The yields were as follows: Oats following cowpeas and German millet, 1897. Yield per acre. Bus. Grain. 22.8 12.4 10.4 Lbs. Straw. 788 559 229 Oats after cowpeas, vines plowed under..... Oats after German millet, plowed under..... Difference per acre ...................... In this case cowpeas were more valuable than German millet as fertilizer for the following oat crop, the difference in favor of 'cowpeas being 10.4 bushels of oats per acre and 229 pounds of straw." (From Bulletin No. 95, Alabama Experiment Station.) This is an increase of 84 per cent. in grain. IMMEDIATE FERTILIZING EFFECT OF COWPEA AND VELVET BEAN VINES AND STUBBLE ON OATS IN 1898. This experiment is descibed in the following quotation from Bulletin No. 95 of this Station: "May 14, 1897, on poor sandy soil Wonderful cowpeas were sown on two plots., velvet beans on two plots, and German millet on a fifth plot. A sixth plot was prepared and fertilized but left without seed, to grow up in crab grass, poverty weed, etc. Cowpeas and velvet beans were isown in drills two feet apart, German millet broadcast. The millet was cut for hay July 16, yielding 994 pounds per acre. The cowpeas on one plot were picked September 10, yielding 11 bushels per acre. The velvet beans did not mature seed. In September, 1897, 1cowpeas on one plot and velvet 3 he1lw, l114 4 m Iu i' ,,3 i nns LapP I0h'v 1 ("U>:~j nu14 1 t he s41lwde1 441 m11414 1 e e aI X v , 't > lie 1. of X(J reb :I 1:'4 4 1 ,', P 4 (!e !;J 1 11111 (41 II144!4T oi %cl 4 i 1he 21hl44ve IltI' ii iii d (lat . 1 fIi'. I II; s 4 (Il vl 141 a\ nt 1 Eu12 1111 1 1 ph4s iw "Jo 1414c wh~e 11(1 1 "t the4 on1 (W11111I tilL 11lie 4one wlw V 1411124. iX 4 I U 14 i 2Vwy lXX ta le 41 X~n v l t i,',4,!; ru "lt s h444 peen'1 (?l (r< 01 .1 11.1;,; er 1t 1(1i1 i 4 w ilh 220 ( X X luni mis per 14r 1)4411181, taIille4 in 44f lucd 4 th I4148111 h 's lul eing (l ( -1 1H1111d8 -1 sli1p144 plie e 44f l 14luiilte of n144 flitroge411l 1 11 1111 4441 1- rie lml111ills o11 j4 I44edill ci - 441 of~ 444XX Xeve he1X 411411 Fi 444-t. 1. 4)ats following 444' (oNpca oa 44 a 4s 1 iircrbra '444 bl oA1I i 44 r B'ig t; o414th44 1ft 155 Yield per acre of oats grown immediately after stubble or vines of cowpeas, velvet beans, etc. Sj o 1 Grain. Bus. 6 38.7 33..6 28.8 34.4 31.6 7.1 .9.7 8.4 Yield per acre. I Straw. Lbs. 1206 1672 1439 1463 2013 1738 231 361 296 1 Oats after velvet bean vines...................28. 6 Oats after velvet bean stubble.............. Average after velvet bean vines and stubble 4 Oats after cowpea vines.................. 3 Oats after cowpea stubble .................... Average after cowpea vines and stubble.... 2 Oats after crab grass and weeds ............ 5 Oats after German millet .................. Average, after non-leguminous plants...... From early spring there was a marked difference in the appearance of the several plots, the plants being much greener and taller where either the stubble or vines of cowpeas had been plowed under. When the oats began to tiller, or branch, the difference increased, the plants supplied with nitrogen, through the decay of the stubble or vines of cowpeas and velvet beans, tillering freely 'and growing much taller than the plants 'following German millet or crab grass. The difference in the height and thickness of the oats on some of the plots is shown in figures 1 and 2. May 18, 1898, oats on all plots were cut. In this experiment the average yield of oats was 33.6 bushels after velvet beans, 31.6 bushels after cowpeas, and only 8.4 bushels after non-leguminous plants (crab grass, weeds and German millet.) is a gain of 24.2 bushels of oats and nearly three-fourths of a ton of 'straw as a result of growing leguminous or soil-improving plants, instead of nonleguminous plants, during the preceding season. Hlere 156 Undoubtedly this is an extreme, and not an average, case. If cotton seed meal, or other nitrogenous. fertilizer, had been used on all the plots of oats, the plants on plots 2 and 5 would have made better growth, and the difference in favor of the leguminous plants would have been reduced. A gain of five to fifteen bushels of oats per acre as a result of plowing under cowpea stubble or vines would make the growing of cowpeas for fertilizer a profitable operation, and it is far safer to count on such an increase as that obtained in our first experiment (10.4 bushels), rather than to expect such an exceptional increase as that obtained in this last experiment. An unexpected result of this experiment i's the larger crop on the plots where 'only the stubble was left than on those where the vines of cowpeas and velvet beans were plowed under. The plots were of nearly uniform fertility, as judged by the location 'and by the uniform growth of cotton on all plots in 1896. While admitting the possibility that the two west plots (plots 3 and 6) were slightly richer than the two on the east (plots 1 and 4), the writer thinks that the difference in yield was almost wholly due (1) to the fact that the vines (especially those of the velvet beans) were not properly buried by the small plow employed, and (2) that the seed bed for oats was more compact where only stubble was plowed under, a point of advantage, doubtless, in such a dry winter as that of 1897-98. It does not follow that the land will be permanently benefitted by cowpea stubble to a greater extent than by cowpea vines. The reverse is probably true." (From Bulletin No. 95, Alabama Experiment Station.) 157 Residual fertilizing effect on late corn of cowpea and velvet bean vines and stubble. On June 20, 1898, or a month after the harvesting of the oats in the last mentioned experiment, all six of these plots were planted in corn without nitrogenous fertilization, which crop, 'as usual with very late corn on poor upland, was a failure. The yields were as follows: Yields of late corn grown as the second crop after legumes. SYield Increase after Crop in 1897: Crab grass, plowed in ................ German millet, stubble plowed in ....... Cowpeas, stubble plowed in ......... Velvet beans; stubble plowed in ........ Cowpeas, picked; vines plowed in ....... Velvet beans; vines plowed in .......... per acre. Bus. 4.3 7.3 6.2 7.7 6.7 7.9 legumes. 4 1.9 .9 2.1 The fertilizing effects of both stubble 'and vines of cowpeas was scarcely perceptible in the late corn planted eight months after 'and harvested thirteen months after the plowing under of the large amounts of nitrogen furnished by the legumes. Apparently the crop failure jwas not due to deficient rainfall, for this was ample except for about two weeks about the middle of August. The small size of stalks leads to the suspicion that there was a deficiency of nitrogen on all plots. If this nitrogen was lost by being leached out in the draining water this loss must have occurred almost entirely after corn was planted or in July and August; for in 1898 April, May, and June were unusually dry months. On the other hand there was a period of excessive rainfall July 4 to 11 and of still greater excess July 28 to August 6. During this latter 158 period 7.59 inches of rain fell in a space of ten days. The experiment seems to teach that on very light, gray, sandy upland, subject also to surface washing, the fertilizing effects of even large amounts of nitrogen furnished by preceding crops of legumes may be removed from the soil within twelve months after the legume has been plowed in. The lesson might also be drawn that on such soils the planting of any non-leguminous crop after small grain is risky, but that if such a crop is employed the seed should be put into the ground as soon as possible after the removal of the grain crop. An experience like this in 'which the fertilizing effect of the entire or nearly entire growth of the legume was no greater than that of the stubble on either the first or on the second succeeding crop emphasizes the wisdom of utilizing the vines of cowpeas, etc., for food, leaving only the roots and stubble to fertilize the next crop. IMMEDIATE FERTILIZING EFFECT ON WHEAT OF COWPEA AND VELVET BEAN VINES AND STUBBLE. All the plots of the last mentioned experiment were in oats from February to June, 1900. June 23, 1900, certain plots were planted with drilled cowpeas, certain others with drilled velvet beans, and yet others were merely plowed and fertilized with minerals, as were the legumes. Of the two plots of cowpeas, one was cut 'for hay, yielding 2,004 'pounds per acre; on the other 7.9 bushels of seed per acre were picked. One plot of velvet beans was cut for hay, while on the other the vines were left on the ground for fertilizer. The cowpea plants, variety Wonderful, were s'omewhat injured by a fungous disease of the roots; velvet beans, by reason of late date of planting and deficiency in stand, did not make an entirely satisfactory growth. November 9 all plots were plowed, turning under either volunteer grass and rag weeds, or cowpea vines, or velvet bean vines, or cowpea stubble, or velvet bean stubble. The plowing was poorly done with a onehorse turn plow and in sowing the wheat a few days later some of the velvet bean vines were pulled up. The wheat received only mineral fertilizers, and, indeed, practically no nitrogen had been applied to these plots for three years. The yields of wheat in 1900 were as follows: Bushels of wheat per acre after leguninous and nonleguminious crops: Crop in 1899. Crab grass and weeds; plowed in ...... Cowpeas; stubble plowed in. ......... Velvet beans; stubble plowed in........ Cowpeas, picked; vines plowed in .... Yield per Increase by use acre. of legumes. Bus. I Bus. 3.1 280 8.7 11.8 151 4.7 7.8 9.0 5.9 190 Velvet beans; vines plowed in......... 8.5 5.4 174 Both the stubble and the vines ,of the legumes practically trebled the yield obtained on the plots where no legume .had grown. The stubble was at least as effective as the vines, pointing to the greater economy of utilizing the vines for h'ay or pasturage. June 19, 1900, all these plots were planted with Mosby corn, fertilized only with phosphate and muriate of potash. The crop was a failure on all plots, the yield of cured fodder corn ranging from 1,540 to 2,200 pounds per acre, the plots where vines had been plowed in the previous fall showing no superiority over the stubble plots, and very little increase as compared with the plot where no legume had grown. It is impossible to ascertain whether the failure with corn was due to the 160 protracted drought during almost the whole of July or to the leaching out of the nitrogen of the legumes during the latst few days in June, when 5.20 inches of rain fell within a period of four days. The latter explanation seems more probable in view of the fairly favorable rainfall after August 1, 1900, and because of similar failure of the late corn crop on the 'same field in 1898, when there was no long period of drought, but a brief one of even more excessive rainfall. 'The history of these six plots for these four years ending with 1900 as just detailed shows very plainly that the fertilizing effects of nitrogen very quickly disappear on this light sandy sloping field, not underlaid by a clay' or clayey loam subsoil; and that on such soils the stubble of cowpeas or velvet beans was as efficient as the vines, not only for the immediately succeeding crop, but for later ,crops as well. This narrative should add force to the recommendation we have so often given that as far as possible the stems, foliage 'and seed of legumes be utilized as food for animals and only what remains be employed as fertilizer. FERTILIZING EFFECTS OF VELVET BEANS, AND PEANUTS; AS COMPARED WITH CORN, SWEET POTATOES AND CHUFAS. On 'a gray sandy upland 'soil, free from ?stones and underlaid by 'a sandy subsoil, various crops were grown in 1899, for the double purpose of comparing them as to the amount of hog f'ood produced and as to their effeet in enriching or 'depleting the soil. The chufas and a part of the Spanish peanuts were consumed by shoats penned on the field. As the running variety of peanuts failed this season to make any nuts the luxuriant growth of vines was plowed under in the fall, as was also done with the vines of velvet beans and with 161 cowpea vines after the latter had been picked. Only the ears off corn were removed from the land, and the roots of sweet potatoes. Rye, sown broadcast on November 13, 1899, on all what plots, was employed as the crop for effect the varilous 'summer crops had exerted on the fertility of the soil. The fertilizer for rye consisted of the following amount's per acre: 80 pounds of 'cotton seed meal. 160 pound's of 'amo'niated acid phosphate. 64 pounds of muriate 'o'f potash. The effects of the legumes as fertilizers for rye would have been more striking if no cotton seed meal or ammoniated guano had been employed, but the poverty of abthis 'sandy soil made ,some nitrogen avoided on the plots Solute failure of crop was to where sweet potatoes, chuf as and corn had grown. only determining be indispensible if and the green The rye was cut April 13 and April 16, forage at once weighed. No cutting 'of 'rye second made, but the land was turned to other uses. Yields 'was of rye following swxeet potatoes, corn, chuf as, peanuts, cowpeas and velvet. beans. Preceding crop. Yield per acre. Increase from legumes as compared with sweet potatoes. Lbs. % 1080 2200 1080 4280 2600 3360 2360 2852 41 93 41 181 110 142 100 121 INilllrrCr\ C~~ h-C hVZT\I - rY~T\ Cr\rr~ Rye, after sweet potatoes dug (av. 2 Rye, after corn, ears pulled............... Rye, after chufas, eaten on the land. Rye, after Spanish plots) .... . nuts removed.................. Rye, after Spanish peanuts; eaten on the land Rye, after Whippoorwill cowpeas, drilled and picked (diseased)...................... Rye, after velvet beans, entire growth plowed .. ....... in (av. 2 plots)................ Rye, after velvet beans, nearly mature pods . picked, vines plowed in................ Rye, after running peanuts, entire growth )... plowed in (av. 2 plots) ... peanuts; Lbs. 2360 3440 4560 3440 6640 4960 5720 4720 5212 dug and only F~IGURE t.l.' 'rl ful areasL. tf)]lO,inh4 (" Velvt loans: and cliiifas Ilo,,, ( I G !'. C I, Fl im-: I c. l n ,d a u a. ' l wi ) tipaI I is Ii N.) rllnninn N. & IJ 163 The legumes increased the yield in every case as compared with sweet potatoes, the excess ranging from 41 to 181 per cent. Among the non-leguminous plants sweet potatoes was most exhausting to the soil, and chufas, when consumed on the land, the least. This agrees with common observation. In this case the exhausting effects of the sweet potatoes were not due to leaching of the disturbed soil, for all plots were plowed soon after the potatoes were dug. Among the legumes the greatest increase, 181 per cent. was 'obtained on the plot where Spanish peanuts had been consumed on the land by hogs. Since the yield of peanuts here was not excessive, since the growth of tops was only moderate, and since the vines of Spanish peanuts on an !adjoining plot did not greatly increase the yield, we can attribute the increase where hogs had grazed, only to an assumed quicker nutrification of the material that had passed through animals. This view finds further support in the fact that chufas consumed by hogs on the land left the soil in better condition than did either corn or sweet potatoes. Wherever the entire growth of the several legumes was left on the land, with or without being utilized as hog food, the 'succeeding yield of rye was more than doubled. Cotton was grown in 1899 on a plot adjacent to the The rye following cotton yielded 5,560 legumes. pounds per acre, but it is not fair to compare this yield with that following the legumes, because the cotton had been very heavily fertilized, and some of this fertilizer probably remained in the soil to be utilized by the rye. 164 Fertilizing effects of legufles on sorghum grown as the second crop. existed in the soil of 1899, as a result of legumes grown in sorghum wa's sown in drills on this'same field June 19, To 'ascertain what differences'still the summer 1900, all plots being uniformly-fertilized with'acid pholsphate. So that sorghu'm thus becomes the second crop after the various legumes, 'and is intended to reveal the residual or "left over" effects of the summer on sorguhm,, crops of 1899. Residual fertilizing effects of peanuts, cowpeas and velvet beans. Prece~ding crops. Winter, 199, 1900. Summer of 1899. . ... . . . . Sweet potatoes, dug ............. Corn, ears pulled....................... Spanish peanuts, dug; nuts removed. Rye Rye Rye Rye on land........... Spanish peanuts; Rye Cowpeas, picked ......................... . Rye Velvet beans, all plowed in .............. Rye Velvet beans, pods picked................. . Rye Running peanuts, all plowed in .......... Rye Cotton, heavily fertilized................. eaten Increase Yield from legumes as sorghum compar'd with hiay per sweet acre. potatoes. Lbs. Lbs. 5360 400 5760 loss. 4480 loss. 4000 400 5760 1750 7110 2240 7600 960 6320 loss. 4000 5040 6697 1657 . Rye Av., potatoes, corn, cotton.... ........ Av., velvet beans, cowpeas, running peanuts Rye Evidently rye had not exh'austed 'all the fertilizing value of the legu'mes. This second'crop was favorably affected by all the legumes except by Spanish peanuts, the 'benefits of which had disappeared. The average in'crease on the plots where all the other legumes had grown the preceding summer wa 33 per cent. a's compared with the yield on the plots where corn, cotton and sweet potatoes had constituted the summer crops in 1899. 165 RELATIVE FERTILIZING VALUES OF THE COWPEA AND VELVET BEAN. When tested on a number of crops, each grown immediately after the legumes, the percentage increase as compared with corresponding plots that had borne no legume was 128 per cent. from peavines, and also 128 per cent. from velvet bean vines. Additional weight is given to these figures since they represent the average of six tests with each plant. Continuing the inquiry as to their comparative value, we find that the second crop after cowpea vines showed an increase of 37 per cent. and the second crop after velvet bean vines an increase of 48 per cent. This is the average result of two comparable tests with each plant. Comparing these two plants with reference to the fertilizing effect of the stubble on the first crop we find three tests an in crease that is as the average of practically the same fo'r 'the two plants. Combining the results for the vines of each legume as shown in the first and second' succeeding crops with the immediate results from the stubble of each we must conclude that at Auburn the fertilizing values of the This cowpea and velvet bean are practically equal. is true for an acre of each. In the stubble plots the average yield of velvet bean hay has been the greater, that is 4,781 pounds per acre of velvet bean -hay against 3,278 pounds of cowpea hay, so that apparently pound for pound the cured tops of cowpeas have been somewhat more effective than the vines of velvet beans. This is in practical accord with the results of chemical analyses made at this station by Dr. Anderson, who analyzed peavine hay and velvet bean hay from plots where the stubble was used as fertilizer. He found 2.29 per cent. nitrogen in velvet bean 166 vines and 2.46 per cent. of nitrogen in the cowpea vines, both 'samples containing 9 per -cent. moisture. The -nitrogen in the two stuhbles was practically equal, 1 per cent. Let us now consider the results as a whole, combining those for the two plants and 'assuming that the fertilizing value of cowpea vines and of velvet bean vines are equal, and that the stubble of the one plant is as effective as that of the other. In what follows the figures express the average results for cowpeas 'and velvet summer beans considered together under the name legumes. of INCREASE IN THE FIRST 'CRop AFTER PLOWING IN THE VINES OF SUMMER LEGUMES. With cotton as the first crop the increase in seed cotton per acre at Auburn was respectively 367, 546, 696, This is an and 660 pound's of seed cotton per acre. average increase of 567 pounds, worth at 2: cents (equal to 64 cents for lint, $7.50 per ton for $14.17. The yield of seed cotton 'following the vines of the summer legumes exceeded that on plots -where the preceding crop h'ad been cotton to the extent of 32, 64, 83, and 72 per 'cent.' The average increase in the yield of seed) seed cotton attributable to the vines was 63 per cent. (of the legs nes With corn as the first .crop, the increase per acre attributable to plowing in the entire growth of velvet bean's was 81 per cent. or 12.3 bushels, wo'rth, 'at 50 cents per bushel, $6.15. With oats as the first 'crop, the effect Hof the vines of the su'mmer legumes is seen in 'an increase per acre of 10.4, 20.2, 'and 20.4 bushels respectively. The average 167 49 cents per increase per acre was 17 bushels,, worth bushel, $6.80. The icrease in the first crop oats after sunmter lequones twas 81, 240 and 242 per cent., an acerage of 189 per cent. With wheat the incresase 5.4 and 5.9 bushels, an -average of 5.65 bushels per acre, worth at 80 cents per bushel, $4.53. The itcremn et was 174 and 190 per cent. respectively, an average gain of 182 per cent. With sorghuant grown as the first crop after the plow.ing under of the vines of cowpeas and velvet beans, the increase in hay per acre was 1.6, 1.6, 2.07, 'and 3.11 tons, at of was an average gain per acre of 2.1 tons of hay, worth, at $6.67 per ton, $14.02. The percentage gains were 85, 86, 57, and 86, respectively, an avirage of 78 pcr cent. INCREASE IN THE FIRST CROP AFTER PLOWING IN THE STUBBLE COWPEAS AND VELVET BEANS. OF With cotton the yield was greater after velvet bean ,stubble than after cotton to the extent of 18 per cent., or 208 poufinds of seed';cottoln per at 2 acre, worth, o'f -cents per pound, $5.20. With cornt, the stubble of velvet beans afforded a gain of 32 per -cent. or' 4.3 bushels, worth $2.15. With oats grown after the plowing in the stubble -of these summer legumes the increase was 30.3 and 26 bushels, or an average of 28.1 .bushels per 'acre, worth $11.24. This is 'an average gain of 334 per cent. With wheat following the stubble of and velvet beans the increase was 4.7 and 8.7, ant average .{6.7 busitels per acre, twortit $5.36. The gain anmounted to 151 and1 280 per cent. respectively, 'an average of 215 per cent. With soryha'nu the yield of hay increased by the -cowpeas of w'as 168 stubble of the legumesto the extent of 2.01 2.15 tons, an average of 2.08 tons of hay per acre, valued at $13.87. The average increase was 57 per cent. WHAT 'CROPS WERE MOST FAVORABLY AFFECTED BY THE VINES OR STUBBLE OF COWPEAS AND VELVET BEANS. The data in the following table answer this question. and Increase in first crop attributable to vines or stubble cowpeas and velvet beans. of InTests. creaseIn Cotton.................4 63 Corn................ 1 81 Oats.. ......... .3 189 Wheat... . .... 2 182 4 78 Sorghum............1 TEST CROP. of After Legume Vines. After Legume Stubble. No. % Value of of InIncrease Tests, crease. crease. $14.17 1 49 $11.30 6.15 1 32 2.14 6.80 2 334 11.24 No. 0 Value of 4.53 2 215 5.36 14.0211 2(57 ( 13.87 The percentage increase attributable to eitherthe vineis or stubble of co:wpeas and velvet beans was greater with fall 'oats and wheat than with cotton, corn or sorghum. In other words, the crop that was best able to utilize the nitrogen of the legumneswas that one which left the land unoccupied for the shortest tinme between the mnaturing of the legumne and the, beginning of the new growth. Unpublished parallel experiments with hairy vetch employed. as fertilizers confirm. this latter conclusion. indicate that after gume are plowed, under in a sandy soil the seed of -the All the facts before. a us, vines or stubble of succeeding crop should be planted before the lapse of many weeks. The early occupation of the soil by roots of the young plants will serve to retain much nitrogen, which. would be leached out and carried away in the drainage water if the ground should remain unoccupied for several months. the. le- 169 From what has ju'st been said it should not be inferred that we 'are advocating the sowing of the small grains or of any small seed immediately after plowing in a large mass of vines. Instead, sufficient time should be given.for the sloil to become somewhat settled by the action of the rain or of harrow, drag, or roller. Small grain and still 'smaller seed can usually be sown after a shorter interval where the vines of the legume are utilized for hay or pa:sturage, leaving only the roots and stubble to be incorporated, than where the entire growth of the legume is turned under in the fall for fertilizer. If plowing under 'of cowpea vines takes place after Christmas the mtass of vegetable matter will have become so diminished and the stems so weak that the delay in sowing to permit of the compacting of the earth around the vegetable matter will be less necessary, or perhaps unadvisable. But this interval may be quite necessary with velvet belan vines at whatever time they are plowed under, for the mass of matter will be con,siderable and the material is apt to 'be buried in large wads. Referring again to the last table, we see that while the small grains gave the largest percentage increase from the use of a preceding summer legume as fertilizer, the value of the increase was greatest with cotton and sorghum hay. In other words, cotton made more profitable use of either the vines or stubble of the summcr legumes on sandy land than did either corn, oats, or wheat. Sorghum responded freely to the 'abundant supply of nitrogen in the legumes, and it may be accepted as a thoroughly tested proposition that on poor or medium soil any hay plant of the grass 'family will return a large profit for a judicious applicatio. of nitrogen, 170 whether this be in the form of a preceding crop of cowpeas, velvet beans, melillotus, hairy vetch, or crimson clover, or in 'an application of stable manure, cotton seed, cotton seed meal, or nitrate of soda. ROTATION OF CROPS THEIFIRST STEP IN SOIL IMPROVEMENT. 'The general 'statement m'ay be safely made that any ordinary crop (except peanuts, cowpeas and most other legumes) can usually be pro'duced with far greater profit when it fbllows ,some leguminous, plant than when its predecessor is 'some non-leguminous plant, as cotton, corn, the small grains, etc. It may also be added that many, if not most, poor tracts ,of land can be cultivated in the usual farm crops at a profit only when a legume is occasionally grown to supply the necessary nitrogen, vegetable matter, and improvement in texture and resistance to drought. A more general use is urged of some rotation that requires all the cultivated upland of the farm to bear cowpeas or ,other soil-improving plant every second, third or fourth year or oftener. The growing of legumes constitutes the cheapest means of obtaining nitrogenous fertilizers, and on farms where 'a large proportion of the land is devoted to legumes, the fertilizer bills can be reduced by the discontinuance of purchases of cotton seed meal and by the substitution of high grade acid phosphate for the higher priced ammoniated guanos. A highly satisfactory rotation for cotton plantations, which has been widely tested, consists of the alternation in the order named of cotton, corn, and any one of the small grains, with cowpeas between the corn rows and also immediately following the small grains. This three-year rotation gives one-third of the land 11 each year in cotton, the cotton imiediately following cowpeas sown after small grain. One-half the total area be devoted to cotton by-a four-year rotation on this plan, assfollows: Corn with cowpeas, small grain followed by cowpea s,cotton, and 'cotton. ;can THE AVERAGE IMMEDIATE FERTILIZING EFFECTS OF VINES AS COMPARED WITH STUBBLE OF COWPEAS AND VELVET BEANS. Although in the last table comparison of the percentage increase after vines with that after stubble is not strictly legitimate since the number of testswas unequal, yet that table throws.s some light on the mat- ter. A 'strictly accurate of the fertilizing effects of vines and stubble as measured by the crop immediately -following is shown below; in this table'only those experiments are recorded'where 'corresponding ine stubble plots were under identical conditions of soil, date of planting, etc. viomparison !and Increased percentage of With cotton as With corn vine plots over stubble plots. No. of tests. firstdocrop................1 ................... do................2 do........................... % 40 49 With oats With wheat 4' 2 [31] * [20]* With sorghum do....................... ... 2 9 *Yield after legume stubble 31 and 20 per cent. respectively greater than after vines, the latter leaving the land too loose, a condition that could probably have been avoided by better preparation. In the crop immediately following the legumes the vines" afforded the larger yield except circumstances reverse'd this result w'ith when 'acecidental This excess in the first crop due to whe'at and oats. plowing under the 172 vines was here- considerable, but was it sufficient to make this method of disposing of the vines more profitable than to use them for hay? Of the several factors on which the:answer depends, we will first consider the value per acre o'f the increase in the first crop 'immediately 'succeeding the legume, using the values for unit of each crop heretofore assumed (see p....) and omitting results with small grains, for reasons given in the footnote. .a Average superiority of vines over stubble of legumes as Value of inincrease crease 40 49 9 shown, in first crop. No. of tests. With cotton as first crop. ..... With corn as first crop........ With sorghum as first crop... 1 4 2 Increase per acre. 452 lbs. seed cotton $11.30 3.30 6.6 lbs. corn. .5 ton hay.......3.34 Average in favor of vines over stubble.$5.98 The average increase of $5.98 in the value of an acre of the first crop in favor of plowing in the vines as compared with utilizing 'only the stubble for 'fertilizer is evidently so low as to be much less than the value of the 4,030 pounds of legume h'ay per acre obtained from the stubble plots, which should be priced. at not leis than corresponding $10 per ton. As 'a partial offset we must bear in mind that in 'four of the experiments in, plowing under 'cowpea vines the peas were first picked, the aver'age yield in these tests being 11.1 'busihels per acre. There is no off set with velvet beans, fo'r the 'seed such do not -mature in the latitude of Aubur'n. usually we value cowpeas 'at 50 cents per 'bushel, plus the cost of hand-picking, we have a second 'credit for the If vines, the sum being $5.55. Adding this 'to $5.98, the 173 extra value of the first crop after vines, as compared with stubble, we have a total credit for the vines when used as fertilizer of $11.53 per acre in comparison with the value of the ,cowpea and velvet bean hay when utilized as stock food. The average yield of cowpea hay from the stubble plots was 3,278 pounds per acre, and of velvet bean hay 4,781 pounds, or a collective average of 4,030 pounds of legume hay per acre. At $10 per ton, this would be worth $20.15 per ,cre. Subtracting from this, $9.50 as above, we have $8.47 as the difference in the first year's profits in favor of utilizing the vines as hay. However, other factors must be considered before we have satisfactorily determined whether it was most profitable to use the vines after picking the peas or to utilize the tops of both cowpeas and velvet beans for hay; chief 'among these factors are the relative residual fertilizing values of vines and stubble as 'show'n by differences in the yield of the second and subsequent crops after legumes. WHAT IS THE FERTILIZING EFFECT OF VINES AND STUBBLE OF COWPEAS ON THE SECOND 'CROP AFTER THE LEGUME? 'The )answer is found in the following table: Average increase in second crop after legumes. After vines. I After ,tubble. No. of Amt. % No. of Amt. % tests. increase., intests. inIncrease. crease. crease. With corn .......... 5 3.36 bus. 2411 5 1.34 bus. 12 With oats .......... 1 7.75 bus. 54 With sorghum ...... 4 2.15 tons 41 In the second crop after the legumes there was in every case a considerable increase attributa'ble to the use of the vines as fertilizer, 174 The fertilizing effect of the stubble as shown by the second crop of corn is much less than the increment due to the vines plowed under many month's before. There is a sixth test with lorn not belonging in the preceding table, that gives additional data for a comparison of the second-year effects of vines with stubble. we find that the Oombining the results of the six corn grown 'as the 'second crop after legumes afforded a larger yield on the vine plots than on the stubble plots to the average extent of 2.1 bushels per acre, or 14 per cent. tests, THE DURATION OF THE FERTILIZING EFFECTS OF STUBBLE AND VINES OF COWPEAS AND VELVET BEANS. The stubble of these legumes repeatedly so slight effect on -corn grown a's tie 'second crop, (an average of only one and one-third bushels peracre), that we reasonably conclude that two crops mark the limit to, which the benefit's of legume stubble extends in cases w here the soil is sandy and perm b an may exerted as at, Auburn. It is quite possible that the advantages using stubble as fertilizer might have been 'slightly from more enduring in a stiffe'r soil, but in no ,case can such a relatively small amount of vegetable matter and nitrogen 'afforde'd by the -r'oots and stubble influence the succeeding 1crops more than a. few years. It is quite a different matter 'when the vines, representing the entire growth of the legume (except in some cases the pods) are plowed un'der. We have learned from the data in previous tables that the yield where the vines were use'd 'fertilizer was in the first crop, as 63 to 189 per cent. greater than the yield of the crop immediately preceded by 'a non-legumenous and th'at in the second cr'op the increase sponding corre- plant; 175 ranged from 24 to 54 per cent. The effect exerted by the vines of the legumes on the third succeeding crop was tested in only one field, the increase in oats as the third crop after cowpea vines being 3.2 bushels per acre, or 14 per cent. With sorghum planted in 1901 as the fourth crop immediately after the oats were cut, there was a perceptible increase on the plots where the vines of ,cowpe'as and velvet beans grown in 1898 had been plowed under; extremely unfavorable conditions and partial failure of late sorghum detract from the reliability of the percentage figures for this, the fourth crop. For three years or four ,crops the large mass of vines continued to exert some influence. This experiment was condu'cted on a soil of 'the 'stiffest type found on the station farm, which, however, is fairly permeable to water, and which might be described as a reddish loam containing an abundance of large flint stones. We should expect 'an equal mass of leguminous vegetatilon elmployed a's fertilizer on clay or prairie soils to exercise a favorable influence for at least three years, or probably for 'as long 'a period as d'o heavy applications of coarse 'stable m'anure. Local experiments to determine the permanency of the action of the legumes are greatly needed, and cor'respondence is invited from parties wishing to make such tests. It is our expectation to ,continue work along the lines indicated in this bulletin, and it is highly desirable that these investigations should be extended to include soils of a character different from that at Auburn, though the means of doing this in a thoroughly satisfactory manner are not now in ight. In conclusion the writer would reaffirm his previous statement, made in Bulletin No. 107 of this station, as follows: 176 A RATIONAL SYSTEM OF FERTILIZATION. Considering permanency of effect; as well as influence on the crop immediately following, the cowpea and other a cheaper source leguminous plants must be ranked of nitrogen than iis any nitrogenous material which may be bought as comimercial fertilizers. The aim of the cotton farmer should be to grow such 'areas of legumes as will enable him to dispense with the purchase of nitrogenou's fertilizers for cotton, using the funds thus saved to purchase increased amounts of phosphates or other necessary non-nitrogenous fertilizers. The money that would have been necessary to purchase one pound of nitrogen will buy about three pounds of phosphoric acid, or plotash, whic'h larger purchases'of phosphate and potash will enable the farmer to grow heavier crops of legumes. And heavier cropsof legumes trap larger 'amounts of otherwise unavailable'atmospheric nitro- as of gen and result in further 'soil enrichment. In the writer'sopinion the rvost promiising method of increasing the yield cotton per acre and the profits cotton culture is by a more general ase .leguminous of of of plants as fertilizers. These invaluable 'allies are by utilized and appreciated, 'but 'their u'se some might be increased twentyfold with advantage to the current -crop, to the perm'anent upbuilding 'of the soil, farmers an'd to the filling of the farmer's pocket. per cent. Alabama It is putting the case very mildly 'to say that the 'average yield of might be increased by at cotton per acre in least fifty through the general use of legumes as fertilizers. APPENDIX.. Condensed statement of effects of using cowpea and velvet bean vines or stubble as fertilizers at Auburn. Tes tcrop. Amt. per acre, increase. Legumes. Vines or stubble. Plant. -L° _____________ Per cent increase. Yield of Superiority of vines legumes per acre. over stubble Per cnt. 78 1st or 2nd Year From From after grown vines, stubble. legumes 1 I -1 I--Y From Ain't From vines, stubble. per acre. 8 88 Lbs. Bus. bay. vowpeas. 1648 .. 2 1 .... 11.8 I 1.6 1 Cowpea ... Cowpea. Cowpea. Cowpea.... Cowpea... Velvet Velvet Velvet Velvet Velvet bean.... bean.... bean.... bean.... bean.... ( Cowpea... Cowpea. Velvet be.n..... Velvet bean .... Velvet.bea.... SCowpea... Velvet bean .... C owpea. . Velvet bean .... SCowpea.... V. &-S. V. & S. V. V. V. V. V. V. S. V. & S. V. & S. V. S. V. S. V. S. V. S. V. V. V. V. V. .V. Corn. Corn. Cotton Oats. Oats -. Sorghum. S orghum.. Corn. Corn .. . Corn . Corn.. Sorghum. Sorghum. Sorghum. Sorghum . Corn. . Corn . Corn Corn. Cotton . Cotton. . Sorghum . Sorghum . Oats. Oats. 1st 1st 1st 2nd 2nd 1st 1st 1st 1st 1st 2nd 1st 1st 1st 1st 2nd 2nd 2nd 2nd 1st 1st 2nd 2nd 3rd 3rd '01 '01 '99 '00 '00 '97 97 '01 '01 '00 '01 '99 '99 367 5 8* 9.7 32 29* 79 1.6 1.6 12 3 4.3 2.1 ...... .2 86 85 81 32 5.0 11Rn 11 28.............I 32 50 0r 57 ..... .. . . 1 . 3.9 0.1 ... v 33 1 6400. '99 '99 '00 '00 '00 '00 '99 '99 '00 '00 '01 '01 20 ... . 55 3.1 . .. 86 '01 2.2 ....... .. 3.6 . .. . 15 1 6....... 11 2.6 .... .. ...... 546 696 ...... 3.1 3.0 . .. . 3 2**........ 3 2 .... 64 83 61 59 14 14 5360.. 8 .... 2.0 24 10 Velvet bean... V. V. Velvet ben... V. !Velvet bean... S. Cowpas.. Sorghum. 4th '01 '01 '99 0.5 ......... 0.5.........50...... 60......... .... 72.... 72 .............. .... .... Velvet bean... V. Cowpea........V. Velvet bean_ V. Veve ben..S Sorghum. 4th Cotton. . 1st . 1st Corn. .2nd 2d .... .... ..... .. . T. . Cotton. 'ats. Oats. Co... 660 '99 ......... '0 '0') ..... 7.5 .... 208 . .... 18 C. .C 452 40 42.... ...... 14............ 2.6 10.leban..S ............... T. C. F. 1st .1st IVelvet Cowpea........ '97 '98 10.4 20.2 ..... 8......................M. 24 0..... .... 76 bean... V. Oats....1st as. 1t Oats....1st Corn, late 2nd. '98 '8... 20 4...........242........................11 6 3 .. '98......... 26.0......309 '98 21 Velvet bean... S. Cowpea.......V. Cow pea........ V. . v t b a .. b a V Corn, late 2nd. Corn, late 2nd Corn, at . ~ 2nd. W a late st t Wheat Wheat Rye.1st 1st 1st '98......19.........33 '98 0916 '98 .1. .1.7Vlv .. '0 00 . .. . '98 '00 '00. 7 37Cowpea........V. F. 10.1 35 2420..F. 36........ .. 0 7 9 ..............F. .... .... .... ....... F, ...... .... .... ........... F. ~h 190 ...... . 1 .... . 0. 2 6. ... 6Ve ..... F. Cowpea.... . . Cowpea......... V. (Sp. Peanuts ... ft CoRn'gpeanus..A.l.V. Co wpv tea . n.. . . V V V l e .e . A 5.9 4280 2852 32 6 260. ...... 87........ 7 . 28 0 ........... 7 9 F. 31 2004..F. do. nuts remv'd... ent. l.. y e.... . .. Rye ...... 1st [.ly e . . . . . . . 11 t st Sp VevePeans. ... V Sreum y..- 1st s '00 0 '00 '000 ' 1080 82............ ..... 181.......................F. ...... ...... 10.........12 . .... . ...... .... .. F. Fu' F. ............................... 1std 2nd 2nd 2nd '00 '01 '01 . . . . . 110. .. . . . . . . ... 0 2360100..Los........... ....... . . . ... . . . ..... F . ................ .... ..... ............ F. F. F. Run'g Peanuts. ' 11. SCowpeas....V Vel. beans (av.) V *Nitrate Sorghum. Sorghum. Sorghum '01 960 .......... 16 16.. ...... ...... 400 7 7...... .... .... .... 1995........- -37..................................F. of soda used both on non-legume and legume plot. the increase to that on corresponding cowpea plot. Stubble afforded the larger yield. j"f Peanuts eaten by hogs on land where grown. *Reducing