黄土塬区不同水分条件下冬小麦氮肥效应与土壤氮素调节

 在黄土旱塬长期定位研究表明 ,根据小麦生育年降水量施用氮肥 ,将能更好地发挥肥料效益。丰水年、平水年氮肥增产效果极为显著 ,应加大施用量 ;干旱年氮肥效果受抑 ,应减少施用量。氮肥利用率受降水等因素影响 ,年际间变化幅度为 6.4%～ 58.6%。氮肥利用率亦随施用量的增加而降低 ,变化幅度为 2 5.4%～ 42 .9%,且其利用率与施肥利润的高低并不同步。施用有机肥或氮磷有机肥配施、轮作中增加豆科作物 (或牧草 )能有效地调节改善土壤氮素状况

The Effect of Nitrogen Fertilizer Under Different Moisture Conditions and Soil Nitrogen Adjustment in the Loess Highland

A long term fixed position experiment was conducted in Changwu dry highland. The results showed that it would be profitable to apply fertilizers according to the amount of rainfall, in the year of wheat growth. It was recommended that the amount of nitrogen fertilizer should be increased in rain rich year and normal year, and the amount should be decreased in drought year because of nitrogenous effect in different hydrological years. With the effect of some factors such as rainfall N fertilizer use efficiency (NUE) was 6.4%~58.6% in experimental years. NUE also changed in the range of 25.4%~ 42.9% with the amount of N fertilizer applied, the more the N used, the lower the NUE,and NUE and profit in wheat did not keep same step. Applying manure fertilizer or NPM, increasing legume crops in rotation were effective ways to improve nitrogen level in soil.