长期以来,生产上有“种豆子能肥田”的说法,认为豆科作物的根瘸能固氮,收获豆子后留下的根部,能够增加土壤氮素,培肥土壤。这种看法是不够全面的。豆科作物的根瘤虽有固氮的能力,但是光依靠根瘤固氮不能满足自身生长对氮素的需要。据报道,北京地区小麦下茬播种花生,收获时每公顷花生需从土壤中吸收氮素141,54公斤,而根部留存在土壤中的氮素4.98公斤/公顷,根瘤菌固氮量为50公斤/公顷。据 For a long time, the production of “beans can fertilize the field,” saying that the root crops of leguminous crops to nitrogen fixation, harvesting beans left after the roots, can increase soil nitrogen, fertilize the soil. This view is not comprehensive enough. Although the root nodules of leguminous crops have the capability of fixing nitrogen, the light-dependent nitrogen fixation of nodules can not meet the needs of nitrogen growth. It is reported that peanuts were planted in Beijing in the next crop. Peanuts per hectare at the time of harvest needed to absorb 141,54 kg of nitrogen from the soil, whereas the nitrogen retained in the soil at the root was 4.98 kg / ha. The nitrogen fixation capacity of rhizobia was 50 kg / Hectare. according to