Fig. 236. Chinese Soy Beans
The plant will grow on many different kinds of soil, but it needs a richer soil than the cowpea does. As the crop can gather most of its own nitrogen, it generally requires only the addition of phosphoric acid and potash for its growth on poor land. When the first crop is seeded, apply to each acre four hundred pounds of a fertilizing mixture which contains about ten per cent of phosphoric acid, four per cent of potash, and from one to two per cent of nitrogen.
If the crop is planted for hay or for grazing, mellow the ground well, and then broadcast or drill in closely about one and a half bushels of seed to each acre. Cover from one to two inches deep, but never allow a crust to form over the seed, for the plant cannot break through a crust well. When the beans are planted for seeds, a half bushel of seed to the acre is usually sufficient. The plants should stand in the rows from four to six inches apart, and the rows should be from thirty to forty inches from one another. Never plant until the sun has thoroughly warmed the land. The bean may be sowed, however, earlier than cowpeas. A most convenient time is just after corn is planted. The rows should be cultivated often enough to keep out weeds and grass and to keep a good dust mulch, but the cultivation must be shallow.
Fig. 237. Soy Beans
As soy beans are grown for hay and also for seed, the harvesting will, as with the other legumes, be controlled by the purpose for which the crop was planted. In harvesting for a hay crop it is desirable to cut the beans after the pods are well formed but before they are fully grown. If the cutting is delayed until the pods are ripe, the fruit will shatter badly. There is a loss, too, in the food value of the stems if the cutting is late. The ordinary mowing-machine with a rake attached is generally the machine used for cutting the stalks. The leaves should be most carefully preserved, for they contain much nourishment for stock.
Fig. 238. Soy Beans in Corn
Whenever the beans are grown for seeds, harvesting should begin when three fourths of the leaves have fallen and most of the pods are ripe. Do not wait, however, until the pods are so dry that they have begun to split and drop their seeds. A slight amount of dampness on the plants aids the cutting. The threshing may be done with a flail, with pea-hullers, or with a grain-threshing machine.