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利用“差量法”研究了八种一年生豆类作物的固氮力,结果表明:花期后固氮率达60—70％,增施氮肥降低固氮率,增施磷肥提高固氮率。在瘠薄的土壤上,一年生豆类作物植株总氮量约1/3来自土壤,2/3来自空气;但地力高时则相反,2/3来自土壤,1/3来自空气;地力更高时,则全部来自土壤,即使氮磷合理配合,来自空气的最多不超过1/3。种植一年生豆类作物后,土壤氮量较种豆前减少,靠根茬氮的返还不能补偿这一亏损,表明种豆后的茬地土壤肥力有所降低,茬地后效生物学检验证实了这一结论。一年生豆类作物由于根瘤菌的共生固氮作用,固氮量可达10斤/亩以上。
The nitrogen fixation ability of eight annual legumes was studied by using the “difference method”. The results showed that the nitrogen fixation rate reached 60-70% after flowering, the nitrogen application rate decreased, the nitrogen application rate increased. In infertile soils, about one-third of the total nitrogen in annual legumes comes from the soil and two-thirds of the air comes from the air, but on the contrary, two-thirds are from the soil and one-third is from the air. , Then all from the soil, even if the rational coordination of nitrogen and phosphorus, up to no more than 1/3 from the air. After growing annual leguminous crops, the amount of soil nitrogen decreased compared with that of seed beans, and the return of stubble nitrogen could not compensate this loss, indicating that the soil fertility of crop stubble after planting beans was reduced. The stubble bioassay confirmed the This conclusion. Annual bean crops due to rhizobia symbiotic nitrogen fixation, nitrogen fixation up to 10 kg / acre above.