Effects Of Spatial Scale Of Soil Erosion And Quantitative Estimation

Linyi City is located in the Yimeng Mountain area, is one of the most serious soil erosion areas in Shandong Province. Many problems caused by long-standing soil erosion,such as soil broken cutting, rocky area expansion, degradation of natural vegetation and so on, are serious threats to human survival and development. Soil erosion, which is influenced by multiple factors and multi-scale variability, has great harm and Strong sustainability. It is a complex geological disaster facing the current global universal.Based on 3S technology and Chinese soil erosion equation( CSLE), This paper make a quantitative evaluation study on Soil erosion condition of Linyi and scale effect on the dominant factor of soil erosion in the study area, that is to say slope angle and slope length factor. On this basis, with the change of spatial resolution, the paper analyze the resulting variation rule. According to the above, The main conclusions were as follows:(1) Micro soil erosion area of the study area up to 80 % of the total area of erosion. The slight erosion is very serious, have been accounted for 15.62%. There are very obvious medium and high-intensity erosion in the undulating terrain of mountains and hills. Throughout the study area, the more serious soil erosion areas mainly around the mountains, and there is almost no soil erosion failure phenomena in plains.The possible reason is that the altitude of the mountainous area is so high that gradient is great. That scenario argues in favour of the formation of erosion runoff. In the mountainous area,the mainly serious soil erosion area is the foot of the mountains,and the higher up in the area, the lower the degree of erosion. The correlation analysis of soil erosion modulus of the study area and the impact factor found that there is a strong dependence relation of the soil erosion modulus and slope angle and length factor LS, The Pearson correlation coefficients were highest for 0.815, P = 0.001. Thus, The study area rainfall erosivity factor R, soil erodibility factor K, slope angle and slope length factor LS, biological measures factor B and Tillage practice factor affect the occurrence and development of soil erosion.However the topography factor is the dominant factor of the study area in soil erosion. It plays a decisive impact on soil erosion.(2) According to the 90 m, 100 m, 150 m, 250 m and 300 m resolution DEM data, the paper were generated the corresponding slope angle, slope length and LS factor.Compared with several sets of data have found that with the change of grid size, the minimum of that three indicators are remained unchanged, while the maximum and average have undergone significant changes. With the increase of the resolution DEM data, the slope angle is reduced linearly, and the slope length is increasing linearly,and the LS factor present a trend of decreasing linearly. The increase of Grid size will cause a rough surface expression of the actual topography. that is to say, ground details were excluded. the result is that the minimum slope value becomes larger, the maximum slope value becomes smaller, so that the average slope becomes smaller. But with the decrease of the resolution, there are more and more rasters of low level slope length and less and less rasters of high level slope length, resulting in a increase of the mean slope length value within the study area. a trend of decreasing linearly presented by the LS factor explain that the slope angle is the master factor of the LS factor values.