宁夏固原云雾山天然草坡土壤电阻率和含水率的关系及其空间变异

为了解黄土区坡面土壤水分的空间分布,于2010年5月初选择宁夏固原云雾山2个典型草坡上利用多电极电阻仪法(ERT)测定了土壤电阻率的坡面空间分布。分别在长约400m的东南坡向坡面和圆丘坡面的4个长约100m坡向上设置纵向样线,并在样线上多点同步地测定了土壤含水率和电阻率,结果表明:土壤电阻率沿纵向坡面的空间连续性和变异性总体较好,阴坡半阴坡(西北、东北)的土壤电阻率小于阳坡半阳坡(东南、西南),并随土层深度增加而逐渐增大。同时,土壤电阻率随着体积含水率增大而几乎线性降低,其相关关系较好,说明利用土壤电阻仪测定值计算土壤含水率的空间连续发布是定量了解黄土坡面土壤水分空间分布非破坏性的一个适合技术途径。

Spatial variation and relationship of soil resistivity and water moisture on typical grass slopes of Yunwu Mountains

To understand the spatial distribution of soil moisture characteristics along Loess Plateau slopes, the method of multi-electrode resistivity meter (Electrical Resistivity Tomography, ERT) was used to measure the spatial distribution of soil resistivity on two typical grass slopes of Yunwu Mountains at Guyuan in early May of 2010 respectively. One southeast slope had the 400 m length longitude transect, the other had four different longitude transects about 100 m length respectively. Along the two slopes the spatial variation of soil resistivity and water moisture were measured by more points simultaneously. Results showed that the spatial continuity and variability of soil resistivity along the southeast longitudinal slope were general good. The soil resistivity of semi-shady or shady slopes (northwest, northeast) was less than that of semi-sunny or sunny slopes (southeast, southwest), and the soil resistivity increased gradually with soil depth increase. Meanwhile, soil resistivity increased almost linearly with the decrease of volumetric water content with a good correlation. So it was an effective way to understand the spatial distribution of soil moisture on the Loess slope by measuring soil resistivity and calculating soil moisture quantitatively and continuously.