Abstract:In order to study the response of soil structure and soil exchangeable capacity of forest and grass to different measures of Grain for Green Project in Pisha sandstone area, we selected Pinus tabuliformis forest (YS), Caragana korshinskii forest (NT), Populus simonii forest (XY) and Stipa bungeana grassland (ZM) as the research objects and buckwheat slope farmland (QM) as the control. Multi-fractal theory was used to determine the soil particle size distribution (PSD), which measured the fractions of CEC, ECEC and the composition of ECEC (Na+, K+, Ca2+, Mg2+), as well as their distribution status and their correlations.The results showed that:(1) The PSD distribution, heterogeneity and dispersion of grassland and woodland were higher than those of sloping farmland after the implementation of conversion of cropland to forest. In the different soil profiles. Grassland was conducive to increasing the distribution range of fine-grained components and particle size of surface soil. However, in the improvement of the above indicators, woodland was more conducive to the deep soil. Moreover, the increase of soil silt contents and PSD distribution range in Caragana korshinskii forest were the most significant among all the measures (P<0.05). (2)In terms of soil exchangeability, alkaline earth metals (Ca2+, Mg2+) were the main components of exchangeable base in the studied area. The CEC and ECEC values of soil under different measures were ranked as NT > YS > XY > ZM > QM. The exchangeable capacity of grassland surface soil was better than that bottom soil, while that of woodland was opposite. (3)Clay, silt and fine sand were the fine-grained soils and coarse-grained soils that determine soil exchangeable capacity in the studied area, and silt content was the main contributing factor of CEC and ECEC values. Multifractal dimension could well describe the relationship between soil exchangeable capacity and soil particles. It was found that among all the measures of Grain for Green Project, Caragana korshinskii had the best improvement effect on soil particle composition and soil exchangeable performance.