Spatial variability of topsoil features in wind erosion area of northern China

Xueyong Zou 1 ,2, Yilei Zhang1, Jifeng Li1, Hong Cheng1 ,2, Chunlai Zhang1 ,2, Liqiang Kang1 ,2, Feng Zhang1
1State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing, China, 2MOE Engineering Research Centre of Desertification and Blown-sand Control, Beijing Normal University, Beijing, China

The particle-size distribution (PSD), contents of organic matter (OM) and Calcium carbonate (CaCO3), and gravel coverage are the crucial factors affecting topsoil features, and consequently influencing on land use and soil wind erosion intensities. The aim of this study was to understand the topsoil features in wind erosion area of Northern China, and to provide the basic data for sustainable land use and management, as well as estimating soil wind erosion. For this purpose, we used the topsoil data of the PSD, OM content, CaCO3 content and gravel coverage derived from 612, 608, 503 and 2608 topsoil sample sites, respectively. The values of these components from each site were loaded on the corresponding geographic coordinates, and then implemented spatial interpolation. The results showed that the areas of sandy loam, loam, loamy sand and silty loam accounted respectively for 39.53%, 21.05%, 16.31% and 12.15% of total area, other eight types of soils together account for 10.96% of the total area. Respectively comparing the spatial distributions of these components with the maps of land use and soil wind erosion intensity, we found that grasslands mainly distributed in the areas of sandy loam soil with highest OM content, medium CaCO3 content and lowest gravel coverage; cultivated land mainly distributed in the areas of loamy soil with medium OM content, highest CaCO3 content and medium gravel coverage; deserts mainly distributed in the areas of loamy sand and sand soil with lowest OM content, lowest CaCO3 content and highest or lowest gravel coverage. The serious soil wind erosion mainly occurred in the higher gravel coverage areas except for a part of the sandy deserts without gravel coverage. This phenomenon, which seems illogical, was because the values of weather factor calculated from The Revised Wind Erosion Equation (RWEQ) were highest, the vegetation coverage was very low, and erodible particles hidden among the gravels were abundant. In other areas, these factors affecting soil wind erosion were contrary.