Effects Of Soil Physical And Chemical Properties On Soil Erosion Resistance Of Sloping Farmland In The Three Gorges Reservoir Area

Farming on steep slopes in the Three Gorges reservoir area is very common.Severe soil erosion not only can destroy the land resources,but also can easily cause irreversible damage to water bodies such as rivers and reservoirs.In this paper,typical sloping fields are selected.Through laboratory tests,we have determined and analyzed the physical and chemical properties of soil at each sample point.Use the test water sink and other equipment to measure the detachment capacity of the soil at each sample point under different water flow shear stress.Determine the soil erosion resistance parameters of each sample point by doing linear regression method,to explore the effects of soil physical and chemical properties and different hydrodynamic conditions on soil detachment capacity,and effects of soil physical and chemical properties on soil rill erodibility and critical shear stress were studied,which can provide a scientific basis for the water and soil conservation work in the Three Gorges reservoir area.The main results are as follows:（1）The regional differences in soil physical and chemical properties of each slope farmland are obvious.There is no significant difference in soil physical and chemical properties under mild and steep slopes.（2）We get that the content of soil sand has a significant effect on soil detachment capacity.While silt,organic matter and cation exchange capacity significantly affect the soil separation ability.After analysing works,we found that among the parameters of mean flow velocity,flow depth,flow shear stress,stream power,the prediction effect of stream power is the best.In this paper,regression equations of soil detachment capacity,hydrodynamic parameters and soil physical and chemical properties parameters are also established.（3）The soil rill erodibility of those sample points varies from 0.062 to 0.608 s·m^-1.The critical shear stress is in the range of 0.853-2.057 Pa.Obtained by correlation analysis,the soil rill erodibility is significantly positively correlated with soil sand content,and is significantly negatively correlated with soil silt content,organic matter content and cation exchange capacity.The soil rill erodibility can be predicted by the above-mentioned soil physical and chemical indicators.The correlation between soil shear stress and physical and chemical properties is not ideal,and we requires deeper research.At the same time,we established a functional model of soil erosion resistance parameters on physical and chemical properties.Through comparative analysis,When the WEPP model is used to predict soil erosion on slopel rill erodibility on slope farmland in the upper reaches of the Yangtze River,the predicted value is smaller than the measured value in this study.