Research On Scale Effects Of Influencing Factors In Regional Soil Erosion

Soil erosion is one of the important environmental issues which threaten human survival and development. It is affected by many factors on multi-scale such as topography, rainfall, soil, vegetation, human activities and so on. In different regions, the factors with the scale transformation have different forces to the intensity of soil erosion. This article takes the Yanhe River Basin in the Hilly and Gully area of the Loess Plateau as a typical study area and chooses Universal Soil Loss Equation (CSLE) model to calculate soil erosion modulus on different scales, to analyze each factor's influence and sensitivity to soil erosion, to demonstrate the factor's scale effect when every factor or the combination of various factors have changed. The spatial similarity between soil erosion modulus and its influencing factors is analyzed based on information entropy theory. The results indicated that the order of the factors'importance to soil erosion in Yanhe River Basin is as follows:slope length (LS)> rainfall erosivity(R)> biological practice (B)> tillage measures (T)> soil erodibility (K). Moreover, the spatial similarity between soil erosion modulus and its influencing factors in low presion data is higer than that of high accuracy data; LS is the most sensitivity factor in soil erosion.The soil erosion modulus increase with LS factor's scaling down. Biological practice factor is the second sensitive factor. With the spatial scale enlarging, the average of soil erosion modules becomes larger. When slope length factor and biological practice combine, soil erosion modules decrease with spatial scale increasing. As spatial scale changes, the impact on soil erosion of the combination in both is higher than a single biological practice factor and less than a single slope length factor on soil erosion. While the scale of rainfall erosivity and soil erodibility changing has little influence on soil erosion. However, rainfall erosivity has an important influence on soil erosion with time scale changing. In this article, the scale effects and sensitivity of influencing factors to soil erosion are quantitatively analyzed in Yanhe River Basin. The research result is of great significance to the soil erosion in the similar basin or scale.