1.The results showed that PAM within 30～120kg/hm2 accelerated the reduction of sandy particle (2～0.02mm ) content and the increasing of clay-silt particle(<0.02mm) content , improved the coarsening of soil.
2.The results show that soil organic matter mostly exist in the silt plus clay, and the ratios of carbon to nitrogen become narrow with particle size decreasing.
3.The result of this study shows that, with the increase of soil erosion, the aggregate of>5mm and>0.25mm in particle size, silt and water-dispersion clay decrease.
