Study On Assessment Of Value Losses For Farmland Degradation

With the rapid development of agriculture, the agricultural environmental problems, such as serious degradation of farmland, the rapid decline in soil quality, are becoming more and more prominent in China. In order to increase benefit and achieve the sustainable development in agriculture, force people to review the value orientation of agricultural production and environmental costs. The dissertation aims to explore an Assessment System of Value Losses on Farmland Degradation (ASVLFD), and then starts to do application of assessment in different scales in China. Follow main findings are obtained:Summing up present situation and character of farmland, make a conclusion that is the serious situation of farmland degradation in China, which mostly displayed in grievous soil erosion, expending of land desertification, outspreading of soil salinization in Northern China et al.. Meanwhile overusing of pesticide and chemical fertilizers greatly destroy the balance of agro-ecosystem, a mass of used plastic film are also threatening the agricultural environments. Currently the cropland polluted by sewage irrigation, heavy metals and industrial waste is very popular, the quality of the agro-products and water environment are under a status of potentially contaminated. It's time to newly recognize the huge environmental costs caused by current pattern of agricultural production.Inter to evaluate the value losses on farmland degradation rationally, a multi-level complex index system of AVLFD was established in the paper. The index system is mainly constituted by three-grade indices, including target indicators, analysis indicators and operating indicators. Target indicators are divided into four aspects, they are soil fertility decline, ecological damage, environmental pollution and farmland losing, and according to influence relations each indicator can be further divided into different sub-indicator system; the middle analysis indicators link to the target indicators and operating indicators; and there are total 20 operating indicators used for analysis and assessment directly.According to the request of index system, computing models corresponding with the operation indices are also developed: (1) Main methodologies are adopted for assessment of fertility decline relying on the hypothesis model based on the relationship between soil nutrient content and productivity. (2) Dose models for evaluating value losses of salinization, gleying, desertification and soil & water loss are respectively established for behaving of ecological destroy. (3) Value loss models for farmland pollution are composed by the direct economic loss of farmland pollution, control Expenses, water pollution costs. (4) The assessment of farmland losing is considered from directly production function and eco-services function.The applications of ASVLFD are conducted in national scale and regional scale. Results of national scale assessment shows: In 2004, the total value loss from farmland degradation in the entire country is 146.73 billion yuan, which are respectively equivalent to 1.07% of GDP and 7.07% of the agricultural total output value. Among the total value loss, which caused by the cropland losing, environmental pollution, farmland destruction and cropland fertility decline are separately 42.55 billion yuan, 44.05 billion yuan, 41.60 billion yuan and 18.53 billion yuan, respectively occupying 2.05%,2.12%,2.00%,0.89% of the total agricultural output value. Results of regional scale assessment from Liaocheng city, Shandong Province shows: In the year of 2000, the total value loss from cropland degradation in the entire city of Liaocheng is 1.23 billion yuan, which are separately equivalent to 4.39% of the GDP and 13.49% of the agricultural total output value. Among which, the value loss in the four indices are separately 23.32 million yuan, 108.35 million yuan, 177.48 million yuan and 923.28 million yuan, respectively occupying 1.89%,8.79%,14.40%,74.91% of the total agricultural output value. By comparing with previous studies, the expected results were obtained from the application of ASVLFD.Generally the attempt in the paper for assessing the value loss on farmland degradation is only a preliminary study, many further in-depth groping work should be conducted.