Slope‐scale spatial variability of fractal dimension of soil particle size distribution at multiple depths

Abstract

AbstractParticle size distribution (PSD) is one of the most important properties of soil, and fractal dimension of PSD (FD) is an accurate and useful description of PSD. In this study, PSD at 11 separates for 32 sampling points at six depths in a slope of the Bashang area in the agro‐pastoral transition zone of North China was determined by the pipette method. Spatial variability of FD at the six depths was analyzed using geostatistics and inverse distance weighting interpolation, and the relationships between FD and soil properties and environmental factors were investigated. Results show that the spatial variability of FD is weaker than that of PSD and that FD has strong spatial autocorrelation at most depths, except at the surface layer. With increasing depth, FD tends to decrease, and its spatial variability tends to increase. The distribution of FD varies across the slope. Fractal dimension of PSD of the concave slope is higher than that of the convex slope. Relative elevation is the main influencing factor at the slope scale, and its effects vary at different depths and slope shapes, which are more significant on the concave slope. Slope gradient and vegetation have little influence on FD. Fractal dimension of PSD can serve as a comprehensive parameter to reflect the characteristics of PSD, bulk density, soil organic C, and magnetic susceptibility. Spatial variability of FD at different depths at small scale can contribute to improving the accuracy of predictive soil mapping and more precise soil resource management.