Analysis on Composition and Pattern of Agricultural Nonpoint Source Pollution in Liaohe River Basin, China

The composition and spatial pattern of agricultural non-point source (NPS) pollution was studied in Liaohe River basin which is representative of areas of intensive NPS pollution in Northeast China. Selecting COD and ammonia nitrogen as the major pollutants, the export coefficient method and GIS spatial analysis methods were utilized to analyze the component composition and spatial distribution characteristics of NPS pollution in Liao River basin. The results showed that farmland runoff was the most significant source for the agricultural NPS pollution in the study area. Over 60 percents of the pollution loading was distributed in the Liaohe River mainstream area, and the pollution intensities were stronger in Hunhe River downstream and Liaohe River stem downstream plain sub-basins in Central- Western Liaoning province than in Hunhe River upstream and Taizihe hilly sub-basins in eastern Liaoning province.