| Soil and water conservation is a basic national policy of our country. Not only does serious soil erosion restrict the development of the regional economy, it also has an important impact on the local people’s production and life. Huaihe river basin is located in the east of China, the terrain is relatively flat, the hilly area of about 1/3 of the total area. The hill area is the important source of soil erosion in China and it has serious soil and water loss. In order to effectively control the loss of soil and water in the Huaihe River Basin, the Huaihe River Basin has been incorporated into the fourth(2008-2012) project planning in the key projects of soil and water conservation. The state and local inputs a greater financial, material and human resources in the soil and water loss process of the implementation of key projects. But so far, there is little research on the implementation effect of key projects and the existing reports limited to the summary of the implementation measures, experience and effect of key projects. The changes of soil erosion in the project area as well as the effect of different engineering measures on the prevention and control of soil erosion are lack of specialized research after the implementation of key projects. Therefore, to explore the state of soil and water conservation in key construction projects of the project area of soil erosion prevention and control effect, take small watershed projects in Huaihe River Basin in Dayu project region of Yimeng mountain and Taoling project region of Dabie mountain as the object to provide reference for understanding and evaluating the implementation effect of the national key construction project of soil and water conservation. We used remote sensing survey and ground survey methods to study the changes of soil erosion in the project area after the implementation of key projects and analyzed the effect of different measures on soil erosion control.The results shows:(1) Changes of land use types after the implementation of key projects. The types of land use are mainly slope farmland and terraced field and a small amount of open forest land before the implementation of key projects(2009) in Dayu small watershed slope land of Yimeng mountain. The type of land use changed to terraced field after the implementation of key project(2013) This is mainly due to the type of typical measures decide it in the study area. The type of typical measures incloud terraced project of slope farmland, enclosure and replanting of open forest land that make the original slope farmland to be transformed into the terraced field by the terraced project and the area of the slope farmland is reduced. Open forest land and sloping farmland are the land use structure of the main land use structure that incloud a small amount of afforested slope land before the implementation of key projects(2009) in the Taoling small watershed slope land of Dabie mountain. After the implementation of key projects(2013), the large area of slope farmland and slope forest is reduced and the type of land is optimized through the implementation of the terraced project of slope farmland, enclosure and replanting of open forest land and level-terrace project of slope farmland.(2) Source of soil and water loss of project region. Soil and water loss occurs mainly in slope farmland in Dayu small watershed slope land of Yimeng mountain. Soil and water loss occurs mainly in Open forest land, Slope farmland and Slope forest in Taoling small watershed slope land of Dabie mountain(3) Prevention and control of soil erosion in key projects. The reduction rates of soil erosion area in Dayu small watershed slope land of Yimeng mountain and Taoling small watershed slope land of Dabie mountain were 88.9% and 76.3% respectively, the reduction rate of soil erosion modulus were 76.7% and 72.1%, and soil erosion modulus were 243 t/km2?a and 314 t/km2?a. The effect of prevention and control of soil erosion in Dayu small watershed slope land was higher than in Taoling small watershed slope land, which mainly resulted from two reasons: the allocations of the measures in 2 regions were different, and the control effects of the different measures varied. Yimeng mountain and Dabie mountain belonged to two different climatic regions,and their leading foundations belonged to two different functional areas too. Therefore, the characteristics of soil and water loss on the occurrence, the prevention and control of soil erosion on demand was different.(4) Prevention and control effects of different control measures on soil erosion in key projects. The reduction rate of soil erosion modulus in the terraced project of slope farmland on the 2 regions was 82.5% and 83.8% respectively. The reduction rate of soil erosion modulus in the level-terrace project of afforested slope land was 70.32%. The reduction rate of soil erosion modulus in the enclosure and replanting, and in open forest land was 39.5%, and 55.2% respectively. |
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