Research On Agriculture Non-Point Source Of Nitrogen And Phosphorus Pollution' Total Amount Of Dagu Watershed

With the effective control of industrial and residential point source pollution,non-point pollution has been the major factor of water pollution. As the agricultural NPS is the most important factor for water environment deterioration and lake eutrophication in China, more and more scientists and technologists focus on the control countermeasure and pollution mechanism of agricultural non-point source. Studying and applying advanced non-point sources pollution model in China is not only the need of theoretical study of NPS pollution model, but also the need of the practices of NPS pollution control in China.As the biggest river in Jiaodong Peninsula, the Dagu River carries the most amounts of runoff and sand among rivers emptying into Jiao Zhou Bay. As the Dagu River brings annually a large amount of silt and dissolved pollutant into Jiao Zhou bay, the Dagu watershed is the main source of inorganic nitrogen and phosphorus of Jiao Zhou Bay. With the implementation of synthetically renovating project in Dagu watershed, the point source pollution has been under good control, so non-point source pollution will become one of the main reasons for pollution in Dagu watershed. Therefore the study on non-point source pollution in Dagu watershed has very high theory value and realistic meaning.Firstly, Dagu watershed is chosen as the study object. The actuality of agriculture non-point source pollution in this area is studied based on comprehensive investigation. An agriculture non-point pollution model: AnnAGNPS is introduced to simulate the load of nitrogen and phosphorus in 2007.The feasibility to use this model in Dagu watershed is proved. The results showed:(1) There are 2182 tons total nitrogen and 209 tons total phosphorus discharged from the Dagu watershed. The soluble nitrogen that is 1714 tons, accounts for about 78.08% of the total nitrogen, and the particle nitrogen is 468 tons accounting for about 21.92% of the total nitrogen. The soluble phosphorus that is 121 tons, accounts for about 58% of the total phosphorus, and the particle phosphorus is 88 tons accounting for about 21.92% of the total phosphorus.(2)CN,F and n are chosen to analyze as the sensitive parameters of AnnAGNPS model. The results are showed: The effect on P is more serious than on N. F has much effect on P, and CN has much effect on N.(3)Through the different project of fertilization we can known that: the loads of TN and TP are linearly related with the amount of application of fertilizer, reduce the amount of fertilizer and rational application of fertilizer will cut down the loads of TN and TP markedly. The changes of absorbable nitrogen and phosphorus are not obvious, but the soluble nitrogen and phosphorus become more as the increasing of the amount of application of fertilizer. That proves that the soluble form is the primary form of nitrogen and phosphorus into the water.Finally, on the basis of designing the best management practices rationally, we give some methods and advice on control and management for the agricultural non-point source pollution of Dagu watershed.