控制坡度条件下黄土高原不同质地坡面土壤侵蚀研究

Research on slope soil erosion of different textureson the Loess Plateau under slope control

基于模拟降雨试验探讨坡面土壤侵蚀坡度效应的作用机制,通过多元线性回归控制协变量分析黄土高原典型区域坡度对径流深和侵蚀模数的影响。结果表明:(1)土壤侵蚀坡度效应与土壤质地、坡面侵蚀方式密切相关。砂质壤土坡面,土壤入渗量和坡面径流均受坡度的影响,入渗量最小值与径流速率最大值出现在15°坡面处;砂质黏壤土坡面,25°和15°坡面土壤入渗量较大、径流量较小,20°和10°坡面土壤入渗量较小、径流量较大;黏壤土坡面,20°和25°坡面入渗量较大、径流量较小,10°和15°坡面入渗量较低、径流量较高;壤质黏土坡面,不同坡度下土壤入渗量与径流速率近似一致,土壤入渗量几乎不受坡度的影响。(2)坡度与侵蚀动力参数之间具有很好的线性关系。砂质壤土坡面,临界径流剪切力和功率随坡度的增加而增加;砂质黏壤土坡面,临界径流剪切力和功率最大值出现在20°坡面;黏壤土坡面,临界径流剪切力和功率随坡度的增加而增加;壤质黏土坡面,临界径流剪切力和功率在15°~25°坡面随坡度的增加而降低。

Based on the simulated rainfall test,the mechanism of slope effect of soil erosion was discussed.The influence of slope in typical areas of the Loess Plateau on runoff depth and erosion modulus was analyzed by multiple linear regression with control covariates.The results showed that:(1)The slope effect of soil erosion was closely related to soil texture and slope erosion mode.On the sandy loam slope,soil infiltration and runoff were affected by the slope.The minimum infiltration and maximum runoff rate appeared on the 15°slope.For sandy clay loam,the 25°and 15°slopes had higher soil infiltration and lower runoff,while the 20°and 10°slopes had lower soil infiltration and higher runoff.On the clay loam slope,the infiltration on the 20°and 25°slopes was larger and the runoff was smaller,while the infiltration on the 10°and 15°slopes was lower and the runoff was higher.For loam clay slope,soil infiltration and runoff rate were approximately the same under different slopes,and soil infil tration was almost not affected by the slope.(2)There was a good linear relationship between the slope and erosion dynamic parameters.On sandy loam slope,the critical runoff shear force and power increased with the increase of slope.On sandy clay loam slope,the maximum critical runoff shear force and power appeard at 20°slope.The critical runoff shear force and power increased with the increase of slope on the clay slope.Moreover,the critical runoff shear force and power decreased with the increase of slope from 15°to 25°on the loamy clay slope.This paper provides theoretical support for soil erosion prevention and control and regional land use management on the Loess Plateau.