Abstract:Thicketization of vegetation for the increased abundance of shrub, Caragana microphylla, has been widespread under overgrazing in the semiarid grassland, Inner Mongolia. During this process, the cycling of nutrients is progressively confined to the zones of litter accumulation beneath shrub,and spatial heterogenity of soil organic carbon (SOC) and soil total nitrogen (STN) tends to increase, and results in the formation of the islands of fertility. It is hypothesized that there is the positive feedback betw...