| Chaohu Lake Basin was located in central Anhui Province, including of Hefei, Feidong, Feixi, Chaohu, Hanshan, He County, Lujiang, Wuwei and Shucheng. It was one of important economic areas in Anhui Province. The soil erosion database was established based on meteorological data, soil type maps, land use maps, DEM, remote sensing image and statistical yearbook. Combined with the natural and human environment in the basin, the factors of CSLE was amended and amplified. The distribution characteristics of soil erosion in Chaohu basin was analyzed.On the basis of the "08GB" and actual soil and water conservation, the environmental benefit was assessed. Compared no vegetation and artificial protection measures of potential soil erosion with CSLE calculation under the condition of vegetation cover and artificial protection measures, the value of environmental benefit could be calculated under the vegetation cover, tillage measures and engineering measures currently. The following were main conclusions:(1)The major soil loss was micro soil erosion in Chaohu Basin and the total annual erosion was0.61×108tt. The micro and slight erosion type were the largest of total erosion accounts for86.58%. Moderate erosion was11.17%and only2.25%was strong and very strong erosion. Micro soil erosion was the largest soil loss in area and slight erosion secondly. Strong erosion and very strong erosion only accounted for0.13%and0.01%.(2)The soil was eroded seriously in the direction of northeast and southwest, other directions belonged to micro erosion due to plains. In addition to Chaohu, Wuwei and Hanshan, other cities and counties were eroded slightly. The annual erosion of Shucheng, Wuwei and Hanshan were the largest but Hefei was the minimum. The erosion modulus of HanShan was the highest and the second was ShuCheng and WuWei, other cities and counties were lower than average annual soil erosion modulus.(3)The largest erosion area was less than5°slope that accounted for88.41%. Less than25°slope was the highest in total erosion, accounting for94.27%. Only0.58%erosion area had the greatest soil erosion modulus from25°to35°slope, and then to decline from top to bottom in turn. (4)At an altitude of200m below the erosion area accounted for95.44%; the erosion amount proportion was the largest under200m in total erosion, the second was in the200-300m elevation band.200-300m accounted for the highest of erosion modulus, and then showed a trend of decline.(5)The annual erosion of paddy field was4327.51t·km2·a-1, accounting for64%of the total. Forest land was followed. Only11%erosion area had16%erosion amount. The grassland erosion was minimal. Dry land had a smaller proportion of all land use patterns in erosion area and annual erosion, but the erosion modulus was the highest, achieving7414t·km2·a-1.(6)The soil conversion and water retention capacity of Chaohu Basin were0.41×1010t/a and0.1×1010under current conditions of vegetation cover and artificial soil and water conservation measures.(7)The total economic value of economic benefits was0.52X1010million yuan. Among them, the value of nitrogen, phosphorus, potassium and organic matter were0.72×109million yuan,0.59X109million yuan,0.37×1010million yuan and0.18×109million yuan. Value of decreasing deposition and decreasing delay were0.47×106million yuan and0.13×107million yuan. And useless land value in Chaohu Basin was0.41×103million yuan. In addition, the value of water conservation, tourism benefits and agriculture were0.14×106million yuan,0.26X107million yuan and0.45×107million yuan.(8)Three major industrial was increasing at present. The proportion of primary industry declined and the second industry rapid growth, the third industry development was slow. Although people’s income increased, there was no significantly improved living standards. The employment benefits was0.31×106million yuan. The ability of farmland to resist natural disasters was enhanced and so as to the effects of natural disasters on agricultural production by water conservancy.(9)The value of negative ions, absorption of pollutants, the dust detaining and noise reduction were followed as0.16×104million yuan,0.49×104million yuan,0.63×103million yuan and0.24×107million yuan. Meanwhile, the product of vegetation was0.16×108t and value of vegetation NPP was0.61×106million yuan in Chaohu Basin. The amount of carbon fixation and oxygen release were0.16×1014t and0.54×1013t, and their value were0.2×1012million yuan and0.54×1012million yuan. |
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