贵州山区坡耕地土壤可蚀性研究

目的]研究贵州山区坡耕地土壤可蚀性。方法]针对贵州山区坡耕地,通过小区径流法和分析测试开展土壤可蚀性研究。结果]用Sharply等提出的公式计算出的可蚀性K值变异系数小,K值相对稳定和精确,是贵州山区坡耕地土壤可蚀性K值计算的适宜方法。坡耕地A层的K值随着年份的增长,呈下降的趋势,整个土层可蚀性强、抗侵蚀弱,侵蚀的危害大。通过4年不同种植制度和利用类型的影响,不同土层的K值都下降,其中A层下降1.26%~12.34%,B层下降1.29%~13.80%,C层下降1.26%~10.80%,ABC三层平均下降3.17%~11.64%。除工程梯化处理外,草地、分带轮作、经果林、粮草间作、植物篱、混交林处理的K值下降幅度都高于农民处理,下降幅度的顺序是草地分带轮作经果林粮草间作植物篱混交林。结论]种树种草有利于坡耕地可蚀性的改善和耕地质量的提高。玉米与其他植物间套作,提高覆盖度和增加生物种类,有利于坡耕地可蚀性的改善。

Study on Soil Erodibility of Slope Cultivated Land in Mountainous Area of Guizhou

Objective ] The research aimed to study soil erodibility of slope cultivated land in mountainous area of Guizhou. Method ] For slope cultivated land in mountainous area of Guizhou, soil erodibility was studied by residential runoff method and testing. Result] Variation coefficient of erodibility K value counted by formula put forward by Sharply et al. was small, and K value was stable and accurate. It was suit- able method counting soil erodibility K value of slope cultivated land in mountainous area of Guizhou. K value of A layer at slope cultivated land presented decline tendency as time increase. Soil erodibility at whole soil layer was strong, erosion-resistance capability was weak, and e- rosion hazard was great. By influences of different planting systems and usage types in four years, K values at different soil layers all declined. K value declined by 1.26% - 12.34% at A layer, 1.29% - 13.80% at B layer, 1.26% - 10.82% at C layer and 3.17% - 11.64% at ABC three-layer. Except engineering ladder processing, decline magnitude of K value by grass, zonation rotation, economic fruit forest, grass and crop intercropping, hedgerow and mixed forest was all higher than that by farmer deal. Sequence of decline magnitude was grass 〉 zonation rotation 〉 economic fruit forest 〉 grass and crop intercropping 〉 hedgerow 〉 mixed forest. Conclusion] Planting trees and grass was favorable for improving erodibility of slope cultivated land and farmland quality. Intercropping maize and other plants, coverage improvement and species increase were favorable for improving erodibility of slope cultivated land.