“以磷增氮”是指通过对农作物,特别是豆科作物施用磷肥,促进作物根瘤的形成和根瘤菌固定空气中的氮素,以增加作物的氮素营养和土壤含氮量。有人做过试验,不施磷肥的红三叶草根部,10株仅有5个根瘤,施粉状过磷酸钙的有56个根瘤,可见施磷肥有“以磷增氮”的效果。 “Nitrogen by phosphorus” refers to the nitrogen nutrition and soil nitrogen content of crops are increased through the application of phosphate fertilizer to crops, especially leguminous crops, to promote the formation of crop nodules and rhizobium nitrogen fixation in the air. Some people have done experiments, no phosphate red clover roots, 10 only 5 nodules, powdered superphosphate 56 root nodules, phosphorus can be seen with “phosphorus by nitrogen” effect.