The Encyclopedia Americana (1920)/Soy bean
SOY BEAN, a leguminous plant (Glycine hispida), sometimes incorrectly called soja bean, native to southeastern Asia. It has been cultivated from ancient times and in some countries, notably Japan, it forms an important article of food. It was introduced into England in 1790 and into America some years later, where it was first grown principally in the southern States. Its use as a food for man has not become general except in its original home in Asia, and it is only within recent years that its value as a feed for stock has brought it to the attention of the western countries. The soy bean is an annual, two to four feet high. It has branching, hairy stems with trifoliate, hairy leaves. The flowers are inconspicuous, of pale lilac or violet color, and the fruit is a broad, two- to five-seeded pod, covered, like the rest of the plant, with stiff, reddish hairs. The seeds vary in color according to variety. When grown for the seed the crop sometimes yields as high as 40 bushels or more to the acre, but the average is much less. As a forage crop it makes as high as two to three tons of cured hay per acre. The fact that the flowers are self-pollinated gives it an advantage over many other legumes in introducing it into new regions. (See Dolichos). Innumerable varieties and forms of the soy bean have been developed in the original home of the plant. Several different varieties have been introduced into the United States, these being distinguished largely according lo the shape, size and color of the seed, in the degree of hairiness and in the time required for the plants to reach maturity. The early varieties are preferred when the plant is grown for seed, while the latter give better results as forage crops. Some of the advantages claimed for it as a crop are that it is able to gather the food of sustenance in relatively poor land and by its power to assimilate nitrogen from the air to enrich the soil in which it grows. It is relatively sure of producing a crop of seeds very nutritious to livestock, for which it is adapted to use in various forms.
Soy beans require about the same conditions for growth as corn, but have somewhat better powers of resisting drought. The seed is not planted until the ground is thoroughly warm in the spring, and the earlier varieties are grown with fair results by planting after an early grain crop has been harvested. When planted for forage the seed is often sown broadcast, but where a crop of beans is desired it is better to plant in drills. The stage of growth at which to harvest depends upon the use to be made of the crop. In the United States the soy bean is grown exclusively as a feed for stock, in pasture, as a soiling crop, for hay, or as a green manuring crop. The green feed and hay are excellent for cows in milk. The beans are usually fed in the form of meal and owing to the richness in protein and fats have been found of peculiar value in compounding feed rations. Fed in connection with less concentrated feeds and grains having a lower protein content, results have been obtained that show the soy beans to compare favorably in feeding value with cottonseed meal. The peanut is the only raw vegetable that contains as high a percentage of digestible protein and fat.
The soy bean is prepared for use as human food in a variety of ways in Japan, where it furnishes the protein that is lacking in a diet of rice. The plant is also grown in Europe and used there to a limited extent as human food. Since the beans contain no starch they are sometimes recommended as food for persons suffering from diabetes; a soy-bean bread has been manufactured for this purpose. Under the name of coffee bean, the soy beans have been placed on the market in America as a substitute for coffee.
In the United States the soy bean is best adapted to the southern and central States. It is not adapted to the States along the northern border or to the States west of the Rocky Mountains. In those States where it thrives it is especially valuable to soils that have become depleted of their nitrogen. The chemical composition of both bean and fodder adapts it especially to use as a balance ration in connection with corn and makes its cultivation desirable where no other protein feed is available. Consult ‘Farmer's Bulletin’ (Nos. 58, 372, 509, United States Department of Agriculture, Washington 1897-1914).