SONG Feng-Bin, YANG Fu-Yi, LI Jing-Lin, SHAO Qing-Chun, CHEN Guo-Shuang
For the demand of national economical development in given region and on the basis of natural and social economical status in small valley of Shengshui Town, the development of integrative restoration and management mode of water and soil loss and ecological agricultural mode were studied, at the same time, the ecological, economical and social benefits were supervised and estimated. On the basis of these, we developed the ecological agriculture mode with high effectiveness, established the integrative and complex agricultural ecological system, and realized the harmonization and unification of ecological benefit, economical benefit and social benefit in small valley of semi-mountain area. These modes have the important appliance foreground and extensive popularization value in semi-mountain area and homoplastic areas.In the mode of ecological economical forest with the function of soil and water reservation, ecological garden had significant benefit with average profit of 7369 yuan (RMB) per hectare, profit margin of 27.53% per yuan cost and labor productivity of 53.61%. Biological output increased to above 18.2-39.2 t/ha in the year of 2000 from 11.8-19.4 t/ha in the year of 1998.The corrasion modulus on slope surface declined above 70% and pathway flux also declined above 50%.The solid exploitation mode with forest, fruit, reservoir, rice has got not only significant economical profit, but also distinctive ecological profit. Before exploitation, the clay inflowing to small reservoir every year make the bottom of reservoir get silt of 3.7-4.2 cm. That is, 1.72 kg/m2 of soil was lost before exploitation, but only 0.49 kg/m2 from 1999 to 2000, declining 71.5%. Because of the increment of vegetation cover degree, the quantity of soil and water loss significantly decreases in the areas of catchments. The ecological environment was protected effectively. In this mode, fish output increased to 556.3 kg/m2 from 375 kg/m2 before exploitation, rice yield increased to 6500 kg/m2 from 5100 kg/m2 before exploitation. On the basis of the characteristics of semi-mountain area, the complex ecological system with the union of fishing, stock raising, grass, forest, fruit and grain was constructed. Within the system every links made up and promote each other, materials and energy was cyclically used in multilayer and many ways. The assistant energy out of system was devoted as little as possible, the production cost was economized and high effectiveness and low cost was realized. Therefore, this mode and technological measures could be extended and applied in analogous areas. Furthermore, the construction of ecological agriculture mode with high effectiveness is the most important content, the sduty group deployed the research work in three sites with an area of 308 ha, at the same time, we used the remote sensing and computer technology for supervising, reviewing, and programming entirely for Shengshui Town, started up the "greenness action" program, these all get actively radiative and driving effect for Liuhe ecological environment construction and other cities and counties.
where ω is the weight of each index, Ei is the commonality of each index. Since the commonality means how much the index can stand for the factors, it is reasonable to assign the weight among indexes using this method. It is proved that economic vulnerability degree contributes the most to synthetical vulnerability degree, social vulnerability degree is the next, and ecological vulnerability degree means the least. Second, Sichuan Province is taken as an example to test its effect of the application,results show that the area with highest and higher synthetical vulnerability degree takes up 85.88%, from which we can get the conclusion that vulnerability degree of Sichuan Province is high as a whole; in addition, synthetical correlative degree and single index correlative degree show that synthetical vulnerability degree and key restrictive factors differentiate a lot among regions, which means different measures should be taken according to different key restrictive factors.Zoning results show that Chengdu, Panzhihua and Deyang belong to the most slight degree, Zigong belongs to slight degree, Mianyang, Neijiang, Guang'an and Meishan belong to middle degree, Luzhou, Suining, Leshan, Nanchong, Yibing, Dazhou, Bazhong and Ziyang belong to severe degree, Guangyuan, Ya'an, Aba, Ganzi and Liangshan belong to the most severe degree. Last, a conclusion is given that application of extension method to regional vulnerability evaluation is practical, but one disadvantage of this method should be pointed out that Kj(vi) is the distance between vi and (a0i,b0i), which makes it more difficult to compare the regions belong to the same degree. But with the development of calculating method of correlative degree, extension method will supply vast vistas on researches of natural border identification and natural elements zoning.
