Cost-Benefit Analysis On Management Practices Of Agricultural Non-Point Source Point Source Pollution In Yixing

Agricultural non-point source pollution treatment and management will be a complex and long-term task due to its widely distributed, long period and other characteristics.A comprehensive management programs,considering the enginering and management practices and local economic conditions will be an effective way to control agricultural nonpoint source pollution.In addition, there is a close correlation in the agricultural nonpoint source pollution and the pursuit for rural economic.So it is necessary to analyze and evaluate the cost and benefit of the treatment practices of gricultural nonpoint source pollution in order to obtain sound management practices, which not only reach environmental goals but also have economic fessibility and optimization.The paper takes Yixing City as the research object.,and tries to analyze the enviromental and economic benefit of different management practices under the same background conditions from the view of enginering economics.The following are main conclusions:For the pollution status in the study area, design six kinds of practces:soil testing and fertilizer, medium-sized biogas digesters, rural sewage treatment projects, methane-generating pit for farm household, eco-ditch (drainage, pond), riparian vegetation; and survey and estimate their total cost, economic and environmental benefits;and make a comperhensive evaluation ahout these practices using net present value, net present value ratio and other indicators. From the microscopic point of view, only considering the economic benefits, only the soil testing and fertilizer and medium-sized biogas digesters are economic fessibility, and sort these measures with the economic benefits, the result is that: soil testing and fertilizer>medium-sized biogas digesters> methane-generating pit for farm household> eco-ditch (drainage, pond)> riparian vegetation. In macro perspective, also taking environmental benefits into account, all practices are economically reasonable and feasible except sewage treatment project, and the priority order is:soil testing and fertilizer>medium-sized biogas digesters> eco-ditch (drainage, pond)> methane-generating pit for farm household= riparian vegetation> rural sewage treatment projects. So in practice, when planing enviromental pracices, we should consider the times, the investment restrictions and the focus of plan to make reasonable choice between different practices.Detailly calculate these practices'capacity to reduce the nitrogen and the phosphorus pollution factors of agricluture non-piont pollution source and found that there is a significant difference between them about the abatement capacity. On the whole, the ability to reduce nitrogen pollution factors is significantly greater than the ability to reduce phosphorus pollution factors.For the ability to reduce nitrogen pollution facors, the order is: soil testing and fertilizer>riparian vegetation>methane-generating pit for farm household> eco-ditch (drainage, pond)>medium-sized biogas digesters> rural sewage treatment project; and the priority order to reduce the phosphorus is:soil testing and fertilizer> riparian vegetation> eco-ditch (drainage, pond)> medium-sized biogas digesters> rural sewage treatment projects>methane-generating pit for farm household. So, in order to propose the targeted decision about the treatment of agriculture non-point source pollution, it is very necessary not only to calculate the total amount of pollution, but also need to identify the pollution factors and analyze their urgence.In summary, the paper analyzes and evaluates many treatment practices about agricultural nonpoint source pollution through economic methods, and proves the existence of difference betwwen these practices'cost and benefits, in order to make some asisstance for the plan of treating agricultural nonpoint source pollution.