Characteristics Of Soil Corrosion Resistance And Quantitative Prediction Of Soil Erosion At Small Watershed

Soil corrosion resistance is an important field of soil erosion research and is one of important indicators that judge and evaluate the ability of soil erosion resistance. Soil erosion model that mainly simulate and forecast the processes and the quantities of soil erosion is one of the effective methods that quantitatively studies the soil erosion processes. To reveal characteristics of soil corrosion resistance and quantitative model of soil erosion at small watershed, the research was carried out using the methods of field investigation, laboratory analysis, mathematical model, "3S" technologies at Guangqiaohe watershed of Zixing county, Hunan Province, which located at a tributary of the Xiangjiang River Valley. In this paper, the characteristics of the soil corrosion resistance its spatial differentiation was investigated, the watershed soil erodibility factor K value was calculated, the quantitative forecasting model of soil and water loss was established based on the computer and the "3S" technique, and the quantity of soil erosion was forecasted and analyzed at Guangqiaohe watershed. The major results are as follows:1.The physical and chemical properties of 96 soil samples that were collected during the field survey were determined at laboratory. The indictors of soil organic matter content (X1),corrosion index (X2), soil aggregate status (X3), degree of aggregation (X4), dispersive ratio (X5),dispersive coefficient (X6) were choosed and considered as a corrosion index using SPSS software, and the cumulative contribution rate of the fore three principal components reached by 80.7%.2.Through the statistical analysis of soil erodibility indexes, the average of the organic matter was 25.4g/kg and its variable range was between 2.7 and 69.4g/kg, the corrosion index was from 0 to 100% and its average was by 46%,soil aggregate status between 124.2g/kg and 788.9gkg, average 520.3g/kg; soil aggregate degree from 12.6% to 84.3%, average 57.6%;dispersive ratio from 3.0% to 59.9%, with its average of 15.7%;Soil dispersion coefficient from 0.7% to 30.9% with an average of 11.6% at Guangqiaohe watershed.3.Based on the physical and chemical properties of soil (sand, silt, clay, organic carbon content), the K value was calculate using of EPIC model at the Guangqiaohe watershed. The results showed the range of soil erodibility factor K values varied from 0.14 to 0.42 t·hm2·h/ (hm2·MJ·mm) and its average value of 0.27 t·hm2·h/(hm2·MJ·mm), and Guangqiaohe watershed generally belong to middle eroded degree.4.The prediction model of soil erosion was established based on the Revisory Universal Soil Loss Equation (RUSLE) at Guangqiaohe watershed. The calculating results revealed that the range of soil erosion modulus varied from 0 to 3817 t/(hm2.a), and its average was 78 t/(hm2.a). The total of soil erosion reached 292266t/a, it belonged to the intense erosion level at Guangqiaohe watershed.