云雾山和叠叠沟草坡土壤电阻率和含水率空间差异

Spatial Differences of Soil Resistivity and Water Moisture on Grass Slopes between Diedie and Yunwu Mountains

为了解不同土质坡面土壤含水率的空间分布差异,选择固原黄土区云雾山和石质山区叠叠沟为研究区域,采用多电极电阻仪法,在长约400 m的坡面上设置纵向样线,多点同步连续测定了土壤含水率和电阻率。结果表明:黄土区云雾山土壤电阻率和含水率的相关性较好(R2=0.78),说明通过测定坡面电阻率推求土壤含水率的坡面变化是可行的。云雾山土壤电阻率沿坡面表现为由坡上至坡中逐渐增大,到坡下部又逐渐减小;而固原石质山区叠叠沟坡面从坡上到坡下电阻率逐渐减小。土壤干层特征方面,云雾山草坡在1～3 m土层出现轻度干层,3～4 m出现中度干层,6～17 m出现重度干层;叠叠沟坡面在3 m土层才出现轻度干层,在6 m以及更深层处出现重度干层。

With the aim to understand the spatial distribution of soil moisture along slopes, the method of multi-electrode electrical resistivity tomography was used on two 400 m length grass slopes of Diedie and Yunwu Mountains as study area. Both the two longitudinal transect lines were set up to detect the soil resistivity and water moisture by more points simultaneously and continuously. Results showed that there was a good statistical correlation between soil resistivity and moisture content on Yunwu Mountain （R2 = 0.78）, and this suggested that it was feasible to determine the spatial variation of soil moisture through measuring spatial distribution of soil resistivity on slope. On Yunwu Mountain, the soil electrical resistivity gradually increased from the top slope to the mid slope, and then decreased to the bottom. While, on Diedie Mountain, it decreased from the top slope to bottom gradually; the light, mild and severe dry layers occurred in 1 - 3 m, 3 - 4 m and 6 - 17 m soil layers on Yunwu Mountain respectively ; While, on Diedie Mountain, the light and severe dry layers occurred in 3 m, 6 m and below 6 m soil layers respectively.