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.