The biological enrichment of farmland nitrogen in the soil circle mainly depends on the enrichment of carbon (organization of nitrogen), that is, it depends on the intensity of photosynthesis or the primary production process of organic matter (production of green plants). Usually more than 20 parts of carbon are needed to enrich one part of nitrogen (carbon to nitrogen ratio ≥ 20).
With the biological enrichment of nitrogen in the soil circle, soil fertility continues to increase, crop yields continue to increase, and the ratio of organic nitrogen in the nitrogen material flow continues to increase, thus relying on the secondary production of primary product nutrition (animal production) ) And the corresponding nitrogen cycle has also been greatly enhanced. Under the conditions of our country, the annual harvest of nitrogen per mu of farmland increases by 3 kg (approximately 150 kg of grain and the corresponding straw). When it is converted into feed, one more pig can be raised. Therefore, the biology of nitrogen in the farmland system Enrichment is an important material basis for the development of agricultural production.
Secondly, with the biological enrichment and organicization of nitrogen, nitrogen will gradually accumulate in the soil. The surface accumulation of nitrogen is mainly related to crop roots and corresponding biological activities in a cone-shaped distribution from top to bottom in the soil. Plant residues It is related to factors such as the concentration of human farming and fertilization activities on the surface of the soil.
