The Ecosystem Service Value Evaluation Of Soil And Water Conservation Of Yanhe River Basin

The evaluation of the Ecological service value was one of indirect economic function ways knowing ecosystem, one of universal concern problems. Yan river basin was seriously lost, in recent decades, human actions that were characterized by soil and water conservation projects on a large scale had changed the landuse of Yan river basin: vegetation cover came to recover, ecological environment had improved, soil and water lost decreased, ecological service function came to enhance. This paper was on the basis of ecological service theories and ways, combined with the theories of water and soil conservation, ecology and eco-economics, studied theories, ways and applications of water and soil conservation service value in the Yan river basin ,by field survey and research results in integration basin.(1) On the basis of analyzing water and soil conservation service value, provided contents and ways of water and soil conservation service value for better evaluation of effects of main man-made water and soil conservation actions against ecological environment in Yan river basin, quantitative analysis of synthesized benefits of water and soil conservation investment, and better understanding the place where water and soil conservation was in the ecological environmental construction.(2) In view of many water and soil conservation measures'structure, functions and ecological process, on the basis of many principles such as scientificity, systematicness, independence, practicability, maneuverability, structure a system to fit the evaluation of water and soil conservation service value. There were 4 service categories, water conservation, maintain and improve the soil, fixing carbon and oxygen, product production, and 7 functional indicators, water conservation value, flood control value, soil conservation value, fertility maintenance value, fixing carbon value, releasing oxygen value, raw material production value, food production value, in this system.(3) The change of landuse in Yan river basin showed that: the general trend during 1990 and 2006 was that: farmland, water and land for construction decreased, especially the farmland; forest and grassland increased largely; the change of landuse during 1990 and 2006 reflected the farmland turned to forest and grassland, which showed that effects of water and soil conservation measures.(4) According to the survey results and related documents, combined ways of field survey, experiment and analyzing documents, etc. and experts advices, made sure the value of parameters of all value calculation, comprehensively evaluated the ecological service value in Yan rive. These papers merely evaluated water and soil conservation measures in the water conservation, maintain and improve the soil, fixing carbon and oxygen, product production, but water and soil conservation measures could contribute purify air, sand-fixation, maintenance of biological diversity and cultural entertainment a lot. The functions of carbon fixation and oxygen supply existed at the same time through plants photosynthesis, the value of carbon fixation and oxygen supply could be calculated by the mean value of carbon fixation and oxygen release. The value of carbon fixation and oxygen supply per unit area in shrub was highest, the value was 2599.4 yuan·hm-2(5) Though analysis, different type of landuse and water had different soil conservation measures'ecological service value, and the difference was huge: the ecological service value of forest and grassland was highest, especially the shrub, but forbidden ecological service value was 6.4% less than shrub's, and the direct investment in forbidden was less, so we should enhance the efforts of implementation of banned measures in water and soil conservation. In view of all basin zone, the ecological service value in Yan river basin improved significantly, and the ecological service value in 2006 increased 0.2 billion compared in 1990.