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Abstract

The input of non-point source pollution (NPSP) is becoming the main source of contamination in downstream surface waters, leading the received waters in an eutrophic state and causing harmful algal blooms. Currently, many techniques have proposed to control NPSP. These methods focus on the NPSP control in specific site, rather than in a watershed level. Such unsystematic control often brings the NPSP to diffuse from one site to another, turning the ?end control? process more complicated. In this study, a ?Reduce-Retaining-Reuse-Restoration? strategy (4R strategy) is proposed to control NPSP in watershed level. The proposal has been applied two typical areas, Lake Taihu Watershed, E China which is a common water-net area and Lake Dianchi Watershed, SW China which is a common intensive agricultural area. The ?Reduce? term of the strategy proposed suggests that the contaminants, including nutrients, are decreased in the source, for instance, the optimization of the amount of fertilizer that needs to be applied. The ?Retaining? terms means that the movement of contaminants is limited. Some bio-measures for this purpose include ecological ditch and constructed wetland. The ?Reuse? terms refers to the usage of the wastes, such as the discharged water and the nutrients from soils and/or water, more than once in the designed different ecological engineering. Lastly, the ?Restoration? term involves rebuilding the microorganism habitats, balancing food chain and maintaining sustainable function through the optimization of the communities composition and structure. The results of the two typical areas studied showed that the application of 4R strategy is an effective measure to decrease NPSP, and to improve and maintain the agriculture ecosystems healthy levels.

Biography

Yonghong Wu has completed his PhD at the age of 32 years at the Institute of Soil Science, Chinese Academy of Sciences. He spent two years of studies as a visiting researcher in Griffith University, The University of Western Australia and Arizona State University. As a chief investigator, he has managed more than 10 projects granted by the government of China. His several accomplishments have been acknowledged by local authorities such as Ministry of Agriculture, China, Yunnan Province, China. He has published more than 50 papers in reputed journals and serving as an editorial board member of repute.