Soybeans do not tolerate frost and are photoperiod-sensitive, which means that flowering cannot begin until summer nights grow longer. Plants require abundant moisture and, in the absence of irrigation, do not do well in areas of winter precipitation such as
Soybeans are an important human food because they are unusually complete in proteins; of the eight essential amino acids, soybean contain seven in sufficient quantity and are deficient only in methionine, which can be supplied from wheat or corn. Soybeans are eaten in numerous ways- as a green or dried bean and as the constituent of soy milk, curds, cheese, and various sauces, and are major source of vegetable oil. Soybean protein is increasingly used as a meat imitation, or meat substitute. Soybean product are also important in animal feeds, and the green crop is used for hay, for forage, and as a fertilizer. Industrial uses include the manufacture of glycerin, paint, soaps, linoleum, rubber substitutes, plastics, and printing ink.