稻田流失养分循环利用系统构建研究初探

针对长江三角洲经济发达地区集约化农田化肥投入超量、稻区水体N、P、K富集度超高,农田生态环境遭到严重破坏等现状,该文系统研究了农田流失养分从农田到水体,再由水体回到农田的循环利用过程,并构建农田养分流失循环利用系统工程,为我国农田流失养分循环利用和农业生态环境健康提供科技支撑。研究结果表明：本区域农田面积为18.6 hm2,水稻季农田化肥N、P、K投入量分别为305.7、44.9、150.8 kg·hm-2;整个水稻季本区域农田地表径流量为4 518.0 kg·hm-2,其中N、P、K流失量分别为16.6、0.5、9.6 kg·hm-2,占水稻季N、P、K肥投入量的5.45%、1.07%和6.37%;农田周围净化池塘中水生植物的N、P、K拦截量分别为67.8、8.1、99.7 kg,分别占本研究区域N、P、K流入量的21.84%、90.31%和55.73%。将水生植物还田,晒干水葫芦（Halerpestes cymbalaria）按4 500 kg·hm-2农田施用,可分别减少农田化肥N、P、K的投入量106.2、9.5、105.8 kg·hm-2。该研究成果对于减轻农业生产面源污染,推进农业生产可持续发展具有积极意义。

Primary study on building recycling system of rice paddy loss nutrient

As intensive agriculture in economically developed Yangtze River Delta areas inputs excess fertilizer and N,P,K enrichments of rice water are ultrahigh,agricultural ecological environment has been seriously damaged.Field experiment was conducted by measuring the loss of nutrients from rice paddy to the water and back to the rice paddy from water,to build recycling systems engineering of rice paddy loss nutrient and supply technologic support for recycling systems engineering and healthy agricultural ecological environment.The results show that： The area of rice paddy area of 18.6 hm2,chemical fertilizer N,P,K in rice season inputs were 305.7,44.9,150.8 kg·hm-2;the rice season overland runoff water was 4 518.0 kg·hm-2,in which N,P,K losses were 16.6,0.5,9.6 kg·hm-2,accounting for N,P,K fertilizer inputs of 5.45%,1.07%,6.37% respectively;N,P,K hold-up of the pond aquatic purification plant around rice paddy are 67.8,8.1,99.7 kg,accounting for the study area N,P,K inflows of 21.84%,90.31%,55.73% respectively.Using dried water hyacinth back to rice paddy under 4 500 kg·hm-2 can reduce chemical fertilizer N,P,K inputs by 106.2,9.5,105.8 kg·hm-2.The research achievement is of positive significance to reduce pollution on agricultural production and promote sustainable development of agricultural production.