施肥对农田氮磷污染物径流输出的影响研究

施肥不当是造成农田地表径流 N、P 污染的主要原因。本文采用实地调查与模拟实验相结合的方法,研究了不同肥料品种、不同施肥强度、不同施肥时间与方式对土壤地表径流 N、P 流失的影响。结果表明,农田径流 N、P 的流失量与肥料投入水平有一定的正相关性,施肥后土壤地表径流中总 P 浓度比未施肥前成倍增加。不同肥料品种以硝酸铵最易增加径流中 N 的含量;通过经济与环境协调分析,相对于其他处理而言,一定量的尿素与普钙配合施用可减少 N、P 流失,同时获得较高的白菜产量;就施肥方式而言,深施或穴施比表施可显著降低径流中 N、P 的流失量。

EFFECT OF FERTILIZER APPLICATION ON NITROGEN AND PHOSPHORUS LOSS WITH FARMLAND RUNOFF

Chemical fertilizer application plays an important role in nitrogen and phosphorus pollution of farmland runoff. By means of field survey and simulation test, effects of variety of fertilizer, intensity, timing and manner of fertilizer application on nitrogen and phosphorus losses from farmland were studied in this paper. The results show that excessive application of fertilizer was the primary cause of nitrogen and phosphorus loss from the farmland. Among different varieties of fertilizer, ammonium nitrate remarkably increased the concentration of total nitrogen in the runoff. Compared with other treatments and levels, application of urea coupled with superphosphate and potassium sulphate could reduce nitrogen and phosphorus loss and heighten cabbage yield; Compared with surface application, deep application or pit application can notably reduce nitrogen and phosphorus loss with the runoff.