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As China's population is growing demand for food increases. For the pursuit of food production, a large number of pesticides, fertilizers were applied, combined with vegetation damage, resulting in increasing agricultural waste, soil erosion and water pollution is worsening, the formation of agricultural non-point source pollution. Agricultural non-point source pollution in the spatial distribution is more dispersed, pollution by geography, weather, hydrologic conditions affecting large variety of pollutants and migration and transformation of complex and difficult to monitor pollution. Therefore, nitrogen, phosphorus and other pollutants are directly discharged into water bodies, polluted water environment pollution problem caused widespread concern. Yitong on coastal residents, especially residents in Changchun City, the production, life has great significance. Field survey and data analysis showed that: Since the range is an important watershed grain production base, pesticides, fertilizers and other large investment, combined with large areas of deforestation, leading to a serious loss of water and soil in the study area. Such cases, a large number of pesticides, fertilizers into surface water and groundwater, resulting in a serious agricultural non-point source pollution problems. To solve the above problems, development of agricultural non-point source pollution, the use of remote sensing interpretation MapGIS6.7 software: software-related use ArcGIS9.2 DEM maps, soil maps, diagrams and draw water, treated to meet the required simulation data requirements; establishment of meteorological and soil type and other databases. Based on the study area SWAT software and establishing agricultural non-point source pollution in the model and parameter sensitivity analysis and model calibration and validation. Based on the established agricultural non-point source pollution models, analysis of district agricultural non-point source pollution and characteristics of the process, the results show: 2008 Enter the amount of surface water bodies sediment was 3,458,700. T, total nitrogen, total phosphorus, respectively 10534.27 t and 1132.42t, by precipitation and other factors, about half less than in 1985. 1985 and 2008, the following role-based infiltration into groundwater nitrogen entering surface water were 2.4 times and 5.5 times. By rainfall and characteristics of pollutants, June, July, August pollutant output accounted for about 90% throughout the year, in which the output of total phosphorus and sediment consistent with the law, and nitrogen show different trends. Surface water total phosphorus and total nitrogen output intensity spatially consistent trend, both upstream and downstream river pollutant output is large, in addition, the nitrogen into groundwater downstream higher strength. Studies show that upland agricultural non-point source pollution output intensity maximum, woodland Min: upland area changes, determine the study area pollution output changes, both positive correlation. Finally, relying on foreign mature best management practices (BMPs) theory, combined with the characteristics of the study area were analyzed for the various measures proposed Yitong River Basin agricultural non-point source pollution control and management measures: the establishment of alfalfa vegetation buffer can reduce the amount of pollution more than 65%: the upstream region steep forest and grasslands can be reduced 10-40%. In addition, we should strengthen the laws and regulations, the implementation of the comprehensive management of river basin as a whole, the implementation of tillage, terracing, for crop stubble mulch, rational application of chemical fertilizers and pesticides, which can effectively reduce agricultural non-point source pollution.
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