施用不同氮肥对坡耕地径流中N输出的影响

以山东省泰安东北部刘家庄村坡耕地为研究区域,通过实地监测多次天然降雨中农田养分的流失,研究施肥处理对氮素流失的影响.结果表明,施肥显著地增大了农田径流中氮素浓度及流失量;在相同施肥量的实验条件下,与碳酸氢铵和普通尿素相比,控释尿素可有效地降低氮素流失15%～25%;70%左右的氮素流失发生在监测的前期.合理施肥、降低表土中速效氮养分含量是减少农田氮流失的关键途径之一.

Effect on nitrogen output in farmland with different nitrogen fertilization

It was conducted to determine the effect of fertilizing to nitrogen loss by testing the nutrient loss from the farmland in natural rainfall events. The sloping field was selected to conduct the research in the northeast of Taian, Shandong Province. The results showed that the concentrations of N in the surface runoff were increased sharply, and the mass of N loss during precipitation runoff were also high. Under the same fertilizer level, CR-urea could reduce nitrogen 15 %-25 % loss availably, comparing with NH4HCO3 and usual urea. In the same time, 70% nitrogen loss was occurred in the early stage of rainfall events. Reducing the amount of nitrogen by rational fertilization in the surface of the soil was a key method to decrease the nitrogen loss.