Paddy Field Ecosystem Services Valuation In The Jiang Yan City

Paddy is very important food crop in China. The planting area of paddy accounts for about30%in the national crop acreage. Although the paddy field ecosystem brings the economic value to humans, it has also brought the certain extent harm because of the unscientific management and use of the paddy field ecosystem. For instance, the excessive use of fertilizers caused the eutrophication of rivers, the extensive use of agricultural chemicals led to sharp drop of diversity biological in the paddy fields and so on.This paper discusses the paddy field ecosystem service function value’s integrity evaluation method, based on researching the paddy field ecosystem service value of the conceptual framework and evaluation method. We select the Jiangyan’s paddy field ecosystem as a research object, to carry on the evaluation of the paddy field ecosystem service function value by collecting2008years and1989year correlation data. The main research content and the preliminary results of the paper are as follows:1. The paddy field ecosystem including natural ingredients and artificial ingredients is a semi-artificial and semi-natural ecosystem, which not only has the characteristics of farmland ecosystem properties, but also has the characteristics of the wetland ecosystem properties. The paper has established the paddy field ecosystem service function value of the evaluation index system, which are based on the research of ecosystem service value of farmland and wetlands and combined with the paddy field ecosystem of its own characteristic properties. Evaluation method for some indicators had improved, such as:the negative value of the estimation methods of greenhouse gases CH4, N2O, CO2emissions; the input costs estimationg methods of the paddy field ecosystem.2. The paddy field ecosystem service value mainly includes8aspects:The positive value mainly refers to the value of primary products, the value of gas regulation, the value of maintaining nutrient, the value of water regulation, environmental purification entertainment value and the value of social and cultural landscape aesthetics, etc;The negative value mainly refers to the negative value of greenhouse gas emissions and the surface source pollution, etc. Form the eight indicators evaluatue the Jiangyan’s paddy field ecosystem service value.3, By Jiangyan’s paddy field ecosystem service value of the more comprehensive assessment the results is:in the2008year, the input cost of Jiangyan paddy field ecosystem is1.8billion RMB, the gross value of that is13.08billion RMB, the net value of that is11.28billion RMB; in the1989year, the input cost of Jiangyan paddy field ecosystem is0.98billion RMB, the gross value of that is10.32billion RMB, the net value of that is9.34billion RMB. The most important factor of net value of Jiangyan’s paddy field ecosystem are the fixed CO2volume factor, the release of O2volume factor and adjust the temperature factor that belong to the gas regulation, followed by the production of rice and sraw factors, the volume of greenhouse gas emissions including CH4, N2O and CO2, while the volume of water in paddy fields,the maintaining volume of N, P, K in the paddy fields, input costs, the emissions volume of cotaining N, P fertilizer and pesticide, the absorption volume of SO2,NOX, HF, and the reducing amout of flying ash are relatively small.The results are obtained by the sensitive analysis to the net value of Jiangyan’s paddy field ecosystem service.The paper concludes that Jiangyan’s paddy field ecosystem contributes to human life and production, but the environmental purification function of the system is gradually weakening, and the negative value of surface source pollution is gradually increasing. Therefore, the Jiangyan government and the people there should have an attention on the problems to avoid this system’s service function further damage, the further spread of the surface source pollution. In the paper, the research of Jiangyan’s paddy field ecosystem service value assessment is very good foundation for the construction of ecological agriculture, is good theoretical basis of further more comprehensive studies of paddy field ecosystem, and is a scientific basis of rational planning and management to better paddy field ecosystem.