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氮素是组成生命的基本元素,是植物的主要肥料。1974年斯盖涅.K.J作了一个估计,全球每年的生物固氮量为1.75亿吨,其中,耕地土壤生物固氮量为4,400万吨,超过了目前每年施入土壤化学氮肥4,000万吨的总数。而在土壤生物固氮中,又以共生固氮居首位,达3,500万吨。紫云英和其根瘤菌所构成的共生固氮体系,有很好的固氮作用。我省紫云英栽培面积历年约2,000万亩,占冬种面积80％左右,若按亩产鲜草2,000斤,实际固氮率30％计算,全省紫云英一项,就能从空气中获得24,000吨氮素。这不仅为土壤补充了大量氮肥,而且可改良土壤,使后作在整个生育过程中,获得一致而均衡的营养条件。
Nitrogen is the basic element of life, is the main fertilizer plant. An estimate was made by Skjern in 1974 that global biological nitrogen fixation was 175 million tons per year, of which 44 million tons of nitrogen were fixed in soil, exceeding the current total of 40 million tons of soil chemical nitrogen fertilizer applied annually. In the soil biological nitrogen fixation, the symbiotic nitrogen fixation in the first place, up to 35 million tons. Aspergillus and its rhizobia constitute symbiotic nitrogen fixation system, has a good effect of nitrogen fixation. The cultivated area of our province is about 2,000 million mu over the years, accounting for about 80% of the winter area. If the actual yield of nitrogen per mu is 2,000 kg and the actual nitrogen fixation rate is 30% Obtained 24,000 tons of nitrogen. This not only supplemented the soil with a large amount of nitrogen fertilizer, but also improved the soil so that afterwards, consistent and balanced nutrition was obtained throughout the reproductive process.