毛乌素沙地土地利用/覆被变化对草地土壤物理、化学和矿物学性质的影响

Effects of land use and land cover change on soil physical, chemical and mineralogical properties under grassland in Mu Us sand land of Inner Mongolia, China

In arid and semiarid regions, cultivation and shrub invasion are two important factors to impact grassland. However, there are few studies to compare the effects of cultivation and shrub invasion on soil physical, chemical and mineralogical properties. In this study, three sampling sites, which respectively represent the native grassland, cultivated grassland (farmland), and shrub invasion of grassland (shrub land) in Mu Us sand land, were selected and soil samples were collected and measured for soil particle size distribution (PSD), soil organic carbon (SOC), total nitrogen (TN) and total phosphorous (TP) concentrations, and relative percentages of mineralogical components. Results showed that cultivation and shrub invasion significantly altered the soil PSD, soil C, N and P concentrations and pools, and the relative percentages of soil mineralogical components of the grassland ecosystems. Grassland cultivation and shrub invasion significantly decreased the contents of silt and clay. Moreover, the land cover change from grassland to farmland or shrubland significantly resulted in soil organic carbon, total nitrogen and soil carbonate loss. In this study, we found that grassland cultivation resulted in more sand accumulation and more soil C and N losses than shrub invasion, which indicated that grassland cultivation was stronger than shrub invasion to accelerate soil desertification in Mu Us sand land.