Source apportionment and spatial heterogeneity of agricultural nonpoint source pollution in Ash River basin

In this paper, the empirical coefficient method and equivalent standard method were conducted to analyze the agricultural non-point source pollution load, source apportionment and its effect on the water quality with the help of GIS in Ash River Basin. The results showed that the contribution of different agricultural non-point sources was chemical fertilizerLivestocklivingsoil erosionstraw and the equivalent standard pollution load proportion was 67.46% 16.24% 12.21% 2.69% 1.40%. Water quality condition from the upstream to the down stream was worsening and the TN and TP concentration actually came to bad V class. The high TN and TP concentration caused by excessive chemical fertilizer became the main reason for the deterioration of water quality.