Construction of an integrated technology system for control agricultural non-point source pollution in the Three Gorges Reservoir Areas

Agricultural non-point source pollution (NPSP) is becoming a severe threat and seriously restricting the sustainable development of agricultural economy and rural environment in the Three Gorges Reservoir Areas TGRA). However, limited studies have focused on agricultural NPSP management in TGRA, especially for integrated technology systems with TGRA characteristics. An integrated slopping land/paddy field/hydro-fluctuation belt eco-system (SPHES) was constructed using best management practices in this study. Evaluation results of the SPHES at the comprehensive test demonstration zone showed that ecological engineering interception technologies on slopping land can reduce 80-90 % of sediment, 20-30 % of nitrogen (N), and 25-35 % of phosphorus (P), respectively. The utility of interception and absorption technology under ridge cropping pattern in paddy fields can effectively control inorganic N in sewage and P in external sewage within one week. Biological sequestration technologies of N and P in hydro-fluctuation belt can intercept 30-50 % of total N, 65-95 % of total P, and 75-90 % of sediments. In summary, the comprehensive removal rate of pollutants in agricultural NPSP exceeded 89 % using this eco-system. The work presented here provides the construction of this integrated eco-system for agricultural NPSP controlling, thereby applying to all small watersheds in the TGRA to control and manage agricultural NPSP. This integrated technology system has broad prospects for promotion and application in similar ecological areas.