Farmland nitrogen loss has been identified as the main source of water pollution, which has become a bottleneck of agricultural sustainable development and ecological environmental resource sustainable utilization. To control nonpoint source pollution was extremely urgent for the intensive agriculture in China.Due to its specific characteristics such as strong negative externalities, complexity, and universality the traditional technology for controlling point source pollution could not be simply employed. The ecological compensation, used as a public policy tool to address the global ecological crisis and environmental pollution, has shown the internalization of external effects, and has become a environmental and economic policy to protect field ecological environment in western developed countries.
Taking into account the initial development in China's non-point source pollution control policies and the practical difficulties of watershed pollution control, to explore ecological compensation mechanism of farmland non-point source pollution control is very urgent. Calculating ecological compensation standard is not only the core and key of the ecological compensation mechanism construction and operation, but also related to its success or failure. At present, ecological compensation standard about controlling agricultural non-point source pollution, especially farmland nitrogen, has not been fully studied in China. The current ecological compensation standard for agricultural non-point source pollution mainly considered the opportunity cost for agricultural environment protection or producers' willingness for compensation. However, how many pollutants will been decreased after ecological compensation implementation,or contaminants reduced to what extent before the compensation have not yet been considered. Therefore, the ultimate goal of building ecological compensation mechanism is subtracting the pollutants to some extent and the pollution control targets must be clearly set before estimating compensation standard for agricultural non-point source pollution.
The basis for this compensation is that farmers receive government's compensation based on their reduction in nitrogen fertilization in achieving the optimal ecological economic. In this study, Yi Xing City was used as an example to illustrate the contingent valuation of cost and benefits and explore the ecological compensation standards for farmers' controlling farmland nitrogen non-point pollution. The results showed that: (1)ecological economic nitrogen application amount of grain production in Yixing City was 225.0 kilogram per hectare, the theoretical value of compensation margin for controlling farmland nitrogen non-point pollution was 620.0-7098.0 yuan per hectare; (2)68.3% of the respondents farmers were willing to accept compensation to reduce nitrogen fertilizer and the farmers' willingness of accepting compensation were positively correlated with their farming experience and education; and (3)50.7% of the farmers that were willing to accept compensation chose to reduce the nitrogen fertilizer to the optimal ecological economic nitrogen amount with a compensation standard for farmland nitrogen non-point pollution controlling at 620.0 yuan per hectare.