大豆是一种需肥较多的作物,子粒中蛋白质含量约百分之四十左右,形成每单位干物质需氮量要比小麦、燕麦等多一倍,因之需肥亦较多,虽然在其根系上有根瘤菌起共生作用,能固定一部分氮素,但远不能适应大豆一生营养的需要,为了进一步提高大豆产量,大力增施肥料,是增产的重要关键之一。实践证明,为了保证大豆产量继续跃进,必须因 Soybean is a crop requiring more fertilizer, and the protein content in the grain is about 40%, resulting in a doubling of nitrogen requirement per unit of dry matter than wheat and oats, which in turn requires more fertilizer. Rhizobium plays a symbiotic role in its root system, which can fix a part of nitrogen, but far can not meet the needs of soybean nutrition. In order to further increase the yield of soybean, vigorously increasing fertilizers is one of the most important keys to increase yield. Practice has proved that, in order to ensure that soybean production continues to leap forward, must be due