虽然根瘤菌能为作物提供氮营养,但豆科作物生长的早期,根瘤菌发挥作用之前,还应根据土壤肥力适量为作物补充氮肥。当豆科植物转入生殖阶段后,大量的同化物质向籽实积累,此时根瘤衰败,固氮作用减弱。此外,磷有利于根瘤的发育和提高根瘤的固氮能力,所以要重视施用磷肥。适量的钾、钙营养有利于微生物的大量繁殖。低pH条件下加入Ca~(2+)可使苜蓿结瘤提前,结瘤率提高。因此, Although Rhizobium can provide nitrogen nutrition to crops, it is important to replenish the crop with nitrogen based on the amount of soil available before rhizobia function during the early stages of legume growth. When the legumes into the reproductive stage, a large number of assimilation substances to the seeds of accumulation, when nodules decline, nitrogen fixation weakened. In addition, phosphorus is conducive to the development of nodules and improve nitrogen fixation capacity of nodules, so we should pay attention to the use of phosphate fertilizer. Appropriate amount of potassium, calcium nutrition is conducive to the multiplication of microorganisms. The addition of Ca ~ (2+) at low pH can lead the alfalfa to nodule earlier and increase the nodulation rate. therefore,