Progress of Agricultural Non-point Source Pollution in Erhai Lake Basin: A Review

The control of agricultural non-point source pollution is an unavoidable issue that must be faced in order to protect the water quality of Erhai Lake basin. The characteristics of agricultural non-point source pollution of different agricultural industries, administrative areas, farmland, river entering lake as well as an estuarine wetland in Erhai Lake basin were comprehensively analyzed based on systematic investigation. The positive effects of irrigation, drainage ditches as well as lakeside buffer zones on the agricultural non-point source pollution control in Erhai Lake basin were summarized. The main causes of agricultural non-point source pollution load in Erhai Lake basin were unreasonable fertilization and rotation pattern in garlic fields, production of large livestock such as cows, pigs and beef cattle along with the frequent change of land use. It can not only reduce the load of agricultural non-point source pollution, but also ensure the high quality and suitable yield of crops by reducing the amount of chemical fertilizer, using organic fertilizer instead of chemical fertilizer, adopting rice-Vicia fava crop rotation pattern as well as Vicia fava-garlic intercropping mode within the area. To comprehensively prevent and control agricultural non-point source pollution in Erhai Lake basin, future research should aim to investigate the impacts of rural production, the ecosystem in the lake and the breeding industry on agricultural non-point source pollution.