Loss Of Nitrogen And Phosphorus Monitoring In Paddy Fields Of Shanghai Suburbs And Ecological Blocking System Constructing

The problem of exacerbating agricultural nonpoint source pollution is a seriouscause for nitrogen(N) and phosphorus(P) losses of paddy fields in the suburbs ofShanghai，by building monitoring field for N and P losses and ecological blockingsystem，respectively to research the use of different fertilization means，ecologicalditches and paddy fields of the two different technical means to control N and Plosses，to decrease loss problems of nitrogen and phosphorus in the paddies，to reducethe exacerbation of the water，to decrease the load of the enclosing environment. Theprincipal disquisitive consequences are as follows:（1）Based on the suburbs of Shanghai fertilization habits, through thedevelopment of a standardized monitoring field, while monitoring the loss of N and Pthroughout the rice of paddy, comparatively analysis loss characteristics of N, P inpaddy field system, to explore the transported rules of N, P in paddy field system.Through comparison of analysis the monitoring data by the standardized monitoringfield, and finally to provide a theoretical basis to dominate agricultural non-pointsource pollution.（2）The characteristics of N and P concentrations of surface water in paddy fieldwere closely related with fertilizer and fertilizer types. Monitoring results by thestandardized monitoring field showed that MT treatment was most likely to resultwith water loss of N and P in paddy field. Among distinct fertilization managments,the total loss (runoff load and leaching load) of N and P by MT treatment was thehighest, respectively34.03and4.64kg hm-2. Contrasted to MT treatment, CTtreatment could reduce the total loss of N by14.69%and total loss of P by61.85%;while OT treatment could reduce the total loss of N by29.18%and total loss of P by68.97%. The monitoring results indicated that runoff was the main loss way of N andP in rice fields, fertilizer types were the factors of controlling N and P loss in paddyfields. Slow-release fertilizer in MT treatment may be more suitable for rice growing,but because of its slow-release effect could also result in higher loss of N and P.（3）Ecological blocking system series were as follows: in-convention ricepaddy-Ecological ditch-Paddy wetlands-out. In the total ecological blocking system,the core constituents of the ecological ditch series paddy wetland system, part two asthe ecological functional unit, to play together good landscape benefit and ecological benefit, which has underlying using for long-term. The construction of ecologicalblocking system could benefitly remove N, P and the others, the monitoring resultsshowed that the system average removal rate for N was57.47%, the average removalrate of P was54.82%; Among them, ecological ditch for the average removal rate ofN was17.58%, the average removal rate of P was19.94%; while the paddy wetlandfor the average removal rate of N was36.53%, the average removal rate of P was31.55%; Therefore, the ecological blocking system had a better removal effect for theloss of N, P in the rice fields.