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 ). 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).