SOY BEAN (Jap. si-yan, Chin. shi-ya. soy), Glycine hispida. An upright bushy annual legu minous plant to 4 feet tall, a native of Asia, where it has long been cultivated, especially in China and Japan, and whence it has been introduced into Europe and America. The name soy is derived from the Japanese shoyu, a food prepared from the seeds. The numerous varieties in cultivation vary principally in the color, shape, and size of the seed and the length of the growing period. Besides its use as a forage plant (see below) this crop is also frequently grown as a soil-improver on soils deficient ill nitrogen. It thrives best under conditions favorable to corn culture and on soils of medium texture well sup plied with potash, phosphoric acid, and lime, although it ago gives good returns on light poor soils. If planted for hay or fodder the seed is sown broadcast or closely in drills in the spring when the soil has become thoroughly warm; if for the beans, in drills about three feet apart and cultivated like corn. When used for hay, en silage, o• green fodder the crop is cut when the plants are in bloom. when harvested for the seed, before the pods become ripe enough to burst and scatter the seeds. From eight to ten tons of green forage arc obtained from an acre. About 40 bushels of seed per acre is considered a satisfactory yield, hut sometimes from 75 to 100. bushels are obtained. Insect enemies and plant diseases do not seem to be troublesome.
Soy-bean hay cut at the proper season and well cured has .a high feeding value, hut since the stems become woody and the leaves fall off badly, the crop is put into the silo either alone or mixed with corn ensilage. The seed, being a
very concentrated feed, is usually ground and mixed with other feeding stuffs. Fed alone or with other materials the meal is quite thoroughly digested experiments with sheep showed that 91 per cent. of the protein and S4 per eent. of the total organic matter was assimilated. Similar values of the seed were 87 and 85 per cent.
Though the soy bean is eaten more exten sively in China and Japan than in any other countries, so far as can be learned it is never ..11ost of these soy-bean products, which have been popular from ancient times, are fermented. The cell walls and other carbohydrate materials are broken down, the cell contents rendered more accessible to the digestive juices, and at the same time peculiar and pleasant flavors are de veloped.
The statement is frequently made that the Orientals live almost exclusively upon rice, eat ing little or no meat. It is not, however, gen erally known that the deficiency of protein in the rice is made up by the consumption of large quantities of these soy-bean products, which are said to take the place in the Japanese dietary of meat and other animal nitrogenous foods too costly to be eaten by the populace. They are eaten in some form by rich and poor at almost every meal. A large number of dietary and di gestion experiments have been made in Japan in which soy-bean preparations formed a consider able part of the food consumed. Generally speak ing, the nitrogen was well assimilated. The beans are sometimes used for bread-making, and when roasted as a substitute for coffee.