黄土高原地区农田土壤的硝态氮残留及其生态效应

Nitrate Residues in Farmland Soils of Loess Plateau and Its Ecological Effects

根据文献资料,分析了黄土高原地区农田土壤残留氮素的形态、数量、分布、影响因素及其生态效应,提出了调控土壤氮素残留需进一步研究解决的问题。

Nitrification is the important link of nitrogen cycle in cropland soil. The great part of nitrate nitrogen that produced from above- mentioned biochemical process remains in soil, some of which is absorbed by crop and some changes into N2O by denitrification. Nitrate nitrogen that remains in soil has many serious effects on cropland ecosystem and all environments. First of all, nitrate nitrogen remaining in soil can lead loss of soil nitrogen fertilizer, which reduces the utilization ratio of nitrogen fertilizer; second, nitrate nitrogen remaining in soil is easily leached into ground water by irrigation and rainfall, which leads pollution of ground water; last of all, nitrate nitrogen remaining in soil can lead increase of N2O in atmosphere. N2O is not only a kind of greenhouse gas that can influence rise of air temperature in world, but also a destroyer of ozonosphere in atmosphere. However, nitrate nitrogen remaining in soil is also a valid nitrogen storehouse, providing the valid nitrogen source of crop. Therefore, studying soil nitrate nitrogen residues is very important from both agriculture and environment. It has been paid close attention and become one research hot spot of world. Loess plateau area locates in an intersection of three natural regions of China and is famous for its long history of agriculture production. However, many years of organic and inorganic nitrogen fertilizer inputs have caused serious nitrogen residues in cropland soils. This paper discussed the nitrogen residues in dry land soil of Loess Plateau and their forms, amount, distribution, influencing factors and ecological effects based on the a great deal of recent research work, and proposed the issues for further research.