Study On Agricultural Non-point Soure Pollution Of Mangxi River Basin In Jingyan

Mangxi river is one of the major rivers in Jingyan county, which mainly flows throuth Dafo, Jinfeng, Yancheng, Qianfo, Sanjiang and Wangcun of15villages and towns in Jingyan county. In recent years, with the economy’s rapid development of Jingyan county, the water quality pollution of Mangxi river has become increasingly serious, which is mainly caused by agricultural non-point source pollution. This paper adopts the export coefficient model to study the agricultural non-point source pollution of Mangxi river basin (Jingyan county), which will provide some references for the basin’s agricultural non-point source pollution control planning and measures.First, the comprehensive pollution index method and water quality identification index method were adopted for analyzing the Mangxi river basin’s water quality (Jingyan county) in2011, and the results showed that the basin’s nitrogen pollution was serious. Then using the export coefficient model to estimate the load of agricultural non-point source total nitrogen output and into Mangxi river (Jingyan county). According to the estimation results, this paper analyzed and predicted the agricultural non-point source pollution. Finally.this paper puts forward some management and control measures of agricultural non-point source pollution, and the main research contents and conclusions are as follows:(1) Agricultural non-point source total nitrogen output load of Mangxi river basin (Jingyan county) was1852.2t in2011. Among the non-point source pollutions, livestock and poultry breeding was the main source of non-point source total nitrogen output load, followed by the rural life’s living pollution and the cultivated land, and the contribution rate of non-point source total nitrogen output load was43.32%,31.45%and17.82%respectively, then the contribution rate of the rest land use types were smaller. The non-point source total nitrogen output load of moderate scale farmers and free-range farmers was larger, which accounted for97.08%of livestock and poultry breeding’s non-point source total nitrogen output load. In each kind of land use types, the contribution rate the cultivated land’s output load was the biggest, and under the condition of without reducing basic farmland area, plant-ing trees in cultivated land appropriately output could reduce the non-point source pollution effectively.(2) Agricultural non-point source total nitrogen load into the Mangxi river (Jingyan county) was128.76t in2011. Among the non-point source pollutions, livestock and poultry breeding was the main source of non-point source total nitrogen load into the river, followed by the rural life’s living pollution and the cultivated land, and the contribution rate of non-point source total nitrogen load into the river was41.27%,28.32%and21.44%respectively, then the contribution rate of the rest land use types were smaller. The relative error was13.49%between the estimate load of improved export coefficient model and the basin exit section’s measured non-point source total nitrogen load, which proved that model simulation effect was good.(3) Without consideration of land use change, agricultural non-point source total nitrogen predicted output load of Mangxi river basin (Jingyan county) is2390.40t in2015. Among the non-point source pollutions, the contribution rate of livestock and poultry breeding is the biggest, followed by the rural life’s living pollution and the cultivated land. Lives tock and poultry breeding is one of the leading causes of Mangxi river basin’s agricultural non-point source pollution in Jingyan county.