Characteristics of magnetic susceptibility on cropland and pastureland slopes in an area influenced by both wind and water erosion and implications for soil redistribution patterns

Many areas are influenced by both wind erosion and water erosion, and the overlap of wind and water erosive forces results in serious land degradation. Magnetic susceptibility (MS) is an effective tool for quantifying soil redistribution. This method has been applied successfully in wind and water erosion research, but not in research on soil erosion induced by both wind and water yet. This study attempts to investigate the characteristics of MS in different land uses in a wind and water eroded area and explore their implications for wind and water erosion. A cropland and a pastureland slope in the Bashang area of the Agro-Pastoral Transition Zone of North China were selected, and samples from the two transects were measured for mass-specific low-frequency MS (X-If), frequency-dependent MS (X-fd), particle size distribution and the MS of five aggregate size classes. The results show that there is a high value concentration of x(If )in the middle slope of the cropland, indicating that the soil is transported by water and accumulated on the slope. The correlation between X-If and X-rd in the cropland is obviously weaker than the pastureland, which is a result of SP loss due to wind erosion in the cropland. The mean X(If )of the surface pastureland is half that of the cropland, which suggests there is deposition of exogeneous wind eroded particles with low MS in the pastureland, and they include coarse particles by saltation and creep from local areas and fine particles transported from remote areas. Due to the different sources of the soil particles, the contribution mechanisms of MS on the two slopes are distinct. Human activities associated with tillage also influence the soil redistribution in the cropland. These preliminary results indicate that MS could be applied to the study of soil erosion induced by both wind and water to provide a supplementary perspective achieving spatially explicit results.