Comprehensive Valuation Of The Multifunctionality Of Paddy Field Ecosystem In Hunan Province

The paddy field ecosystem possesses the multifunctionality. The public goods that provided by multifunctionality in the paddy field ecosystem are not endowed proper values, because it cannot be traded in the market. According to the researches of many scholars who are at home and abroad, the comprehensive evaluation is developed for the internality and positive externality like the rice production of the paddy field ecosystem in Hunan, water storage and flood control, conservation of underground water, temperature regulation, the purification of water, biodiversity conservation and the value of landscape and culture and the negative externality like greenhouse gas emission from paddy field, water consumption and agricultural chemical pollution by the ways of creating a reasonable index system of value evaluation and applying the methods of the market value, the replacement cost and analogy in this paper. The results of this research have been represented as below:(1) The value of positive benefits of Hunan's paddy field ecosystem in2008is10.84×1010including the value of the function of rice production1.53×1010yuan, the value of the water storage and flood control0.36×1010yuan, the value of the conservation of underground water3.78×10yuan, the value of the releasing oxygen2.23×1010yuan, the value of fixed carbon dioxide2.24×1010yuan, the value of temperature regulation0.2×1010yuan, the value of the purification of water0.34×1010yuan, the value of biodiversity conservation0.16×1010yuan and the value of landscape and culture0.0022×1010yuan. And the cost value of the negative externality is-5.16×1010yuan including the value of greenhouse gas emissions-3.16×1010yuan, the value of water consumption-1.71×1010yuan and the value of agricultural chemical pollution-0.29×1010yuan. The total value of the multifunctionality of Hunan's paddy field ecosystem in2008is5.68×1010yuan and the value of unit area is14745yuan per hectare.(2) Among the different kinds of the Positive benefits of Hunan's paddy field ecosystem, the value of gas regulation> the value of the conservation of underground water> the value of rice production> the value of the water storage and flood control> the value of temperature regulation> the value of the purification of water> the value of biodiversity conservation> the value of landscape and culture. The service functions of the Hunan paddy field ecosystem are mainly rice production, the conservation of underground water and gas regulation. And its total value is9.78×1010yuan, which is90%of the Positive benefit. Among the different kinds of the negative externalities of Hunan's paddy ecosystem, the impact of agricultural chemical pollution<the impact of water consumption<the impact of greenhouse gas emissions. The impact of greenhouse gas emissions is61%of the whole negative externalities, which represents that the negative externalities of Hunan's field paddy ecosystem in2008is mainly greenhouse gas emission.(3) According to results of this research and in order to keep the sustainability of paddy ecosystem, the government is advised to take some subsidies measures in accordance with the Green Box Policies of WTO to encourage farmers to remain the multifunctionality of the paddy ecosystem; applying reasonably the basic principles of ecology to promote rice production; develop a reasonable system of chemicals to reduce the pollutions; publicizing widely he value of the multifunctionality of the paddy field ecosystem to attract people's attention and further protecting the paddy ecosystem by creating an atmosphere of public opinion.Through the analysis of the results of this research, several conclusions have been drawn that1) The multifunctionality of the paddy ecosystem possesses a great value that is far larger than a single function of material production.2) By comparison with cases of another areas that are at home, different methods of evaluation are adopted in different areas and the values of evaluation of the multifunctionality of the paddy ecosystem are different.3) Cases have indicated that the value of gas regulation, the value of the conservation of underground water and the value of rice production all possess great proportions in the total value of the multifunctionality.