The soybean, lat. Glycine max belongs to the legume plants (N - fixation). It is native to east asia, but widely grown over the world now.
The plant is classed as an oilseed plant rather than a pulse by the UN Food and Agricultural Organization (FAO).
Soybeans occur in various sizes, and in many hull or seed coat colors, including black, brown, blue, yellow, green and mottled. The hull of the mature bean is hard, water-resistant, and protects the cotyledon and hypocotyl (or "germ") from damage. If the seed coat is cracked, the seed will not germinate. The scar, visible on the seed coat, is called the hilum (colors include black, brown, buff, gray and yellow) and at one end of the hilum is the micropyle, or small opening in the seed coat which can allow the absorption of water for sprouting.
Soybeans as well as other legumes contain symbiotic bacteria, called Rhizoibia with nodules of their root systems. These bacteria are able to fix nitrogen from atmospheric, molecular nitrogen (N2) into ammonia (NH3).
Cultivation is successful in climates with hot summers, with optimum growing conditions in mean temperatures of 20 to 30 °C (68 to 86 °F); temperatures of below 20 °C and over 40 °C (68 °F, 104 °F) stunt growth significantly. They can grow in a wide range of soils, with optimum growth in moist alluvial soils with a good organic content. o
The U.S., Argentina, Brazil, China and India are the world's largest soybean producers and represent more than 90% of global soybean production. The U.S. produced 75 million tons of soybeans in 2000, of which more than one-third was exported.
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