Impact of W-OH spraying on pore structure of two typical erodible soils in southern China

The southern red soil region of China is highly vulnerable to water erosion, with Quaternary red clay (QRC) and granite red soil (GRS) representing two typical erodible soils. Although W-OH material is widely used to reduce erosion, its influence on soil pore structure after infiltration remains unclear. In this study, four concentrations of W-OH (0%, 0.5%, 1%, and 2%) were applied to QRC and GRS surfaces, and X-ray computed tomography (CT) was used to determine consolidation depth and characterize pore structure changes. W-OH infiltration depth ranged from 1 to 2 cm in QRC and 1.5–3 cm in GRS, decreasing with increasing concentration. The consolidated layer showed lower porosity, smaller equivalent pore diameter, reduced pore surface area, and lower connectivity density, but higher pore circularity, while fractal dimension and anisotropy showed no significant differences. These results clarify how W-OH modifies soil pore structure to enhance erosion resistance and provide a scientific basis for its effective application in soil conservation.