Best management practices for agricultural non-point source pollution control using PLOAD in Wuliangsuhai watershed

Increased concern has been addressed on non-point source (NPS) pollution, due to the serious lake eutrophication worldwide. The best management practices (BMPs) could provide a rational approach to control the agricultural NPS pollution, which is of great significance for the environmental protection and comprehensive watershed management. The authors calculated the discharge of total nitrogen and phosphorus in Wuliangsuhai watershed by using the pollutant load estimator (PLOAD) model. Fifty-nine watersheds were divided, among which thirty-three watersheds with higher agriculture land percentage (above 50%) were targeted for BMPs, as the pollutant load is heavier in agricultural land than in any other types of land use in Wuliangsuhai watershed. Scenarios of the total NI'S pollutant emission with or without agricultural BMPs were calculated and compared by using the PLOAD model. The results indicated that the emissions of total nitrogen and total phosphorus could be reduced by 54.68% and 41.54%. respectively, which means agricultural BMPs is a rational option for watershed restoration. The result could provide technical support and scientific reference for the protection of aquatic environment and for the formulation of conservation policy in Wuliangsuhai watershed