Research On Soil Water Movement And Soil Erosion Of Primarosols In The Three Gorges Area Of China

The impact of soil profile contracture of hilly weak development soil(granite parent material and shale parent material) on soil water movement and slope erosion principle were studied in this research using in-situ simulated rainfall experiment and indoor test. Through the situ experiments, basic properties of the soil profile differences of parent material were reached, distribution of slope water movement and water migration law in different plot were revealed, the runoff process in different plot with different parent material was analyzed, the relationship between of the slope runoff process and soil erosion were investigated, CT scan was used to analyze the pore distribution in different soil profile layer simultaneously. The main results are as following.(1)Two soil profiles parent material formed belong to the initial stages of soil, there are obvious weak development characteristics. Soil structure and texture of each soil layers affect the saturated hydraulic conductivity, resulting in higher saturated hydraulic conductivity of layer A and lower of layer B in granite parent material plot and t-he shale parent material layer to the contrary.(2)There were significant differences of slope water transport in different plot. Rainfall in granite parent material plot mostly went downward and the corresponding reduced the surface runoff and increased the infiltration, but in the deeper layer the infiltration became less, so that infiltration of water existed in the form of subsurface runoff. Shale parent material cell sur--face water infiltration reduction, a corresponding increase in surface runoff, while the lower more water moving downward in the form of deep infiltration, the less interflow.(3)The runoff process in granite parent material plot first reached a maximum and then achieve a more stable state; and in the shale parent material plot-, the surface runoff showed a sustained increasing phenomenon, which was because rainfall mostly existed in the form of surface runoff.Subsurface-runoff phenomenon existed in two kinds of parent materials, the amount of subsurface-runoff in granite parent material is greater than the of shale parent material plot, under different rainfall intensity, larger rainfall intensity had always been able to promote the increase in surface runoff, the impact on the subsurface flow is not obvious, but in the case of different initial moisture content in the granite parent material plot, the initial moisture content of the process would affect the-surface runoff to a greater extent, and the impact of surface runoff small, for subsurface flow, the lower the initial moisture content, is interflow more; shale parent material in the cell slope, the higher the initial moisture content, the more the slope surface runoff, and the initial moisture content effect of subsurface flow is not obvious(4)Erosion process was- consistent with the trend of the corresponding surface runoff process, slope erosion runoff was strongly influenced by the amount of surface runoff-. Rainfall intensity for different conditions, two cells exhibited slope with rainfall intensity increases, the erosion rate increases phenomenon, and compared with the parent material shale slope area, granite parent material Slope cell with rain intensity increases, the smaller the amount of erosion increases the number of instructions in the granite parent material slope cell, the shale parent material than the district has a strong anti-erosion ability.(5) Soil porosity is a key factor in the impact section of moisture migration, granite soil slope, a pore number, pore ratio and Da value parameters are greater than the C layer, and thus it may be known, in a layer of the preferred path to more than C layer. Therefore, in the soil properties showed a layer of saturated hydraulic conductivity is higher than that of C layer. Soil pore through the influence of different levels of saturated water rate, so that the granite slope area runoff in high interflow and lower surface runoff, so that the granite slope plot showed a higher resistance to erosion.This study proved that three gorges area of China of weak material development effect of soil profile structure on soil water movement and erosion. For granite and shale kerogen slope area in the rainfall process of moisture migration and law of soil erosion of difference, not only by the effects of rainfall intensity and initial water content, nature of the slope itself also to the rules produced great influence. Combining with the CT scan, fully demonstrated the effect of soil profile structure macro process of slope.