Soybean (Glycine max L. Merr.) is a leguminous vegetable of the pea family that grows in tropical, subtropical and temperate climates.
Soybean is an exceptionally nutritive food. It consists of more than 36% protein, 30% carbohydrates and excellent amounts of dietary fiber, vitamins and minerals. Soybean also contains about 20% oil including healthy fatty acids, lecithin and vitamins A and D. A by-product from the oil production (soybean cake) is used as a high-protein animal feed in many countries. Soybean also contains secondary metabolites such as isoflavones, saponins, phytic acid, oligosaccharides, goitrogens and phytoestrogens that may have both positive and negative health effects.
Soybean also improves soil fertility by adding nitrogen from the atmosphere.
Some of the major production constraints include Asian soybean rust, frogeye leaf spot, bacterial pustule, bacterial blight and soybean mosaic virus. Nematodes and insects such as pod feeders (stink bugs), foliage feeders and bean flies feed on soybean plants. These wounds provide entry points for pathogens, and the plant frequently becomes susceptible to pathogenic organisms. Dual-purpose varieties that are tolerant to phosphorus-deficient soils and have enhanced capacity to kill seeds of the parasitic weed Striga hermonthica that attacks cereals are being developed.
Soybean is now cultivated throughout East and Southeast Asia, North America, Brazil and Africa where people depend on it for food, animal feed and medicine. Nigeria is currently Africa’s largest soybean producer at about 600,000 tons annually.