In the southern states, September and October are usually the driest months, and if the crop can be sown at such time as to bring the haying season in these months, this, together with the use of haycaps (Fig. 279), will greatly reduce the danger of loss in curing.
The harvesting of cowpea seed is not yet on a satisfactory basis. The pods are usually picked by hand and afterwards shelled by beating with a flail. Pickers have been patented and tested, but never extensively manufactured nor adopted. Hand-picking, the usual procedure, is too slow. The most rapid method is to cut the vines after most of the pods have matured, using a reaper or scythe; carefully to cure the whole in cocks; and to pass the vines and pods through a shredder, which cracks very few of the peas. Some persons advise running the vines through a grain thresher, driven at low speed and with blank concaves, pre cautions which in our experience have not entirely prevented the cracking of a considerable propor tion of the peas.
Uses.
The cowpea is useful for the following purposes: (1) For the improvement of the land, through the addition of vegetable matter and of nitrogen secured from the soil air.
(2) For forage that may be utilized either as hay, as a soiling crop, for silage, or for pasturage.
(3) For the production of a highly nutritious seed crop that serves as food for mankind and for domestic animals.
(4) As a crop to fit the land for sod, in the North.
The most profitable means of utilizing the crop is to use the top as forage, and to secure in addition the very considerable fertilizing effect of the roots, stubble and other residue left on the land. By this method the forage is utilized twice, once as food for animals and later in the form of barnyard manure, which will then be very rich in nitrogen. If the crop cannot be converted into hay, the next best use is to pasture it, thus leav ing most of the fertilizing material on the land.
The analyses heretofore given show that all parts of the cowpea plant are rich in nitrogen. The hay is similar in composition to wheat-bran, and experiments at the Alabama Experiment Sta tion ( Bulletin No. 123) showed that one ton of cowpea hay was practically equal to 1,720 pounds of wheat-bran in the ration of dairy cows. At this station, the grazing of cowpeas by dairy cows showed a value of about five dollars per acre of cowpeas grown as a catch-crop between the rows of corn, and a value of about eight dollars per acre in low-priced pork when nearly ripe cowpeas were grazed by hogs (Bulletin No. 118). The cowpea makes a satisfactory silage when passed through a silage cutter and well weighted in the silo. It is usually preferable, however, to mix in the silo cowpeas with corn or sorghum.
The coupea as a fertilizer.—What clover is to the North and West as a means of improving the fer tility of the soil, the cowpea is to regions south of the clover-belt. A ton of cowpea hay contains
about forty pounds of nitrogen; hence, with a yield of two tons of hay per acre, we have in the entire plant, including roots and stubble, more than 100 pounds of nitrogen per acre, equivalent to more than in 600 pounds of nitrate of soda. Of the total nitrogen in the plant, that in the roots and stubble usually constitutes 20 to 40 per cent, averaging about 30 per cent.
Crops grown after the stubble of the cowpea, yield considerably more than when following non leguminous plants, but usually much less than when the entire growth of the preceding crop of cowpeas has been plowed under as fertilizer.
Diseases and insect enemies.
In parts of the southern states near the coast, and especially on sandy soil long in cultivation, the cowpea is subject to the cowpea wilt (Neocos mospora vasinfecta, var. traeheiphila) and to injuries of the root by nematode worms (Heterodera ra dicicola). To both maladies the Iron variety is practically or entirely immune. Mildew, leaf-spot and other diseases of the foliage occur, but exten sive damage from these is unusual. The leaves are sometimes eaten by grasshoppers and other insects, Literature.
The literature on cowpeas is extensive. Muck information will be found in the agricultural press and agricultural books. A few bulletins and reports are mentioned here: Alabama (College) Experiment Station Bulletins, Nos. 14, 107, 114, 118, 120, 122 and 123; Ala bama (Canebrake) Experiment Station Bulletins, Nos. 9, 10 and 22; Arkansas Experiment Station Bulletins, Nos. 31, 58, 61, 68, 70 and 77 ; Connect icut (Storrs) Experiment Station Bulletins, Nos. 6 and 23; Reports 1888, 1893, 1895 ; Delaware Experiment Station Bulletins, Nos. 46, 55 and 61; Reports 1892, 1893, 1895 ; Georgia Experiment Station Bulletins, Nos. 3, 17, 23, 26 and 71; Illinois Experiment Station Bulletin, No. 94 ; Ken tucky Experiment Station Bulletin, No. 98; Report, 1902 ; Louisiana Experiment Station Bulletins, Nos. 8, 19, 29, 40, 55 and 72; Michigan Experiment Station Bulletins, Nos. 224 and 227; Mississippi Experiment Station Bulletin, No. 40; Missouri Experiment Station Bulletin, No. 34; New Jersey Experiment Station Bulletins, Nos. 161, 174 and 180; Report, 1893; North Carolina Experiment Station Bulletins, Nos. 73, 98 and 162; Oklahoma Experiment Station Bulletin, No. 68; Reports 1899, 1901 and 1905; South Carolina Experiment Station Report, 18S9; Texas Experi ment Station Bulletin, No. 34; Vermont Experi ment Station Report, 1895; Pennsylvania Experi ment Station Report, 1895; Bulletin, No. 130; United States Department of Agriculture, Bureau of Plant Industry Bulletin, No. 25; United States Department of Agriculture (Agrostology 64), Cir cular, No. 24; United States Department of Agri culture Yearbook for 1896.