The establishment and application of risk assessment index system for agricultural non-point source pollution

This paper based on analyzing influence factors of non-point source pollution in Yitong River basin, chose factors of four aspects--soil type, land use, climate elements and ground water to establish risk assessment system for agricultural non-point source pollution; then used engineering drawing and overlay analysis application in GIS technology, and calculated the power of the weight of each factor by AHP to determine the risk rating index, basing on which agricultural non-point source pollution risk zoning was divided. The research results showed that due to the factors of paddy field use and high-density animal husbandry, it has a higher risk of agricultural non-point source pollution in the river basin and relatively developed cities, and the risk is lower in remote and forest region. The establishment of risk assessment index system for agricultural non-point source pollution can help to guide us in making good use of water and soil resources.