麦季农田流失养分植物拦截技术体系研究

Investigating the plant interception technology system on wheat-season farmland nutrient loss

本研究在农田排水沟渠末端增设农田生态塘,对麦季农田流失水体进行贮留,并通过在生态塘配置养分拦截植物进行养分富集研究,旨在为减轻我国农业面源污染提供技术支撑。小麦季农田设置农民习惯施肥(NN)和优化施肥(EN)2个施肥水平;生态塘种植水芹菜和黑麦草2种拦截植物。结果表明:试验年度麦季农田共发生8次地表径流,麦季农田总地表径流水量为1119.0 m^(3)·hm^(-2)。NN处理农田地表径流水体总N、总P、总K流失量分别为4.5、0.5、4.0 kg·hm^(-2),采用优化施肥能够减少农田地表径流养分流失量,EN处理总N、总P、总K流失量分别为3.9、0.4、3.8 kg·hm^(-2)。本研究灌排单元农田面积为5.2 hm^(2),小麦季其农田地表径流水体总N、总P、总K流失量分别为23.3、2.4、20.8 kg,生态塘中水芹菜和黑麦草拦截农田N、P、K流失量分别为18.0、1.9、22.0 kg,植物养分拦截量占本灌排单元农田地表径流水体养分流失的77.3%、79.2%、105.8%。经折算,生态塘与农田的面积比例以1∶43~50为宜。研究表明,在太湖地区小麦田排水沟渠末端设置生态塘,并配置水芹菜和黑麦草2种养分富集植物,可拦截麦田地表径流氮磷养分超75%,有效减轻农业面源污染。

An ecological pond was built to collect lost nutrients from the wheat-season farm outfall,and vegetables were planted in the pond to explore a new strategy for reducing agricultural production pollution and improving environmental safety.During the wheat season,overland runoff occurred eight times;The total farmland overland runoff was 1119.0 m^(3)·hm^(-2),and the irrigation-drainage cell area was 5.2 hm^(2).Two fertilizer practices were also investigated:the farmers′fertilizer practice(NN)and an optimized fertilizer practice(EN).Overland runoff losses on NN farmland were 4.5(Total nitrogen,TN),0.5(Total phosphorus,TP),and 4.0(Total potassium,TK)kg·hm^(-2).Overland runoff losses decreased on EN farmland;with 3.9(TN),0.4(TP),and 3.8(TK)kg·hm^(-2),respectively.The total overland runoff losses were 23.3(TN),2.4(TP),and 20.8(TK)kg.Celery and ryegrass in the ecological pond intercepted the N,P,and K farmland nutrient losses(18.0,1.9,and 22.0 kg,respectively),accounting for 77.3%(N),79.2%(P),and 105.8%(K)of the irrigation-drainage cell inflow.The scaled ecological pond to farm proportion was 1∶43~50.