薄膜覆盖减少化肥养分流失研究

Reducing Nutrients Loss by Plastic Film Covering Chemical Fertilizers

我国化肥的利用率低,使用量又不断增长,增加了农业面源污染问题的严重性.本研究针对化肥流失主要通过水带走的特性,进行大田试验种植玉米,利用薄膜覆盖所施用的化肥,实现＂肥与水隔离＂,以减少化肥流失.试验一方面观察了不同施肥处理二季甜玉米的生长和产量,另一方面测定了作物对肥料的利用率以及地表径流养分含量.结果表明,在本土壤条件下甜玉米只需施用常规施肥量的70%即可达到高产.甜玉米收获后土壤中碱解氮、有效磷、有效钾的含量比不经薄膜覆盖的显著提高,其顺序为100%施肥量＋覆膜〉70%施肥量＋覆膜〉100%施肥量、70%施肥量〉不施肥.氮、磷、钾肥料的表观利用率分别为42%-87%、0%-3%和5%-15%,覆膜处理一般高于不覆膜处理,特别是在高施肥量情况下更为明显.通过8次径流水的收集测定,无薄膜覆盖的施肥处理的地表径流N、P和K平均浓度分别为27.72、2.70和7.07 mg·L^-1,薄膜覆盖技术处理降低N、P、K浓度的效果分别达到了39.54%、28.05%、43.74%,对于减少农业面源污染和水体富营养化可起到明显效果.

With the low utilization rate of fertilizers by crop and the growing amount of fertilizer usage,the agricultural non-point source pollution in China is becoming more and more serious.The field experiments planting corns were conducted,in which the applied chemical fertilizers were recovered with plastic film to realize the separation of fertilizers from rain water.In the experiments,the influences of different fertilizing treatments on the growing and production of sweet corn were observed.The fertilizer utilization rate and the nutrient contents in surface run-off water with and without the film covering were also determined.Results showed that,with only 70% of the normal amount of fertilizers,the sweet corn could already get high yield under the experimental soil conditions.Soil analysis after corn crops showed that the amounts of available N,P and K in the soil increased obviously with the film-covering,and the decreasing order was：100% fertilizers with film-covering 〉 70% fertilizers with film-covering 〉 100% fertilizers,70% fertilizers 〉 no fertilizer.The average utilization coefficients of fertilizers by the crop were 42%-87%,0%-3%,5%-15% respectively for N,P and K.It was higher with film-covering than that without covering,especially for the high fertilization treatment.Analysis of water samples collected for eight run-off events showed that,without film-covering,N,P and K average concentrations in the runoff waters with fertilizations were 27.72,2.70 and 7.07 mg·L^-1,respectively.And they were reduced respectively by 39.54%,28.05%,43.74% with the film-covering.This can give significant benefits to the decrease of agricultural non-point source pollution and water eutrophication.