From the aspects of physics and chemistry

the processes and characteristics of soil degradation of typical rainfed farmland in the Horqin sandy land were discussed. Results showed that in the desertification process of rainfed farmland

a series of physical and chemical properties worsened associated with losses of soil fine particle materials

including bulk density and pH raised

total porosity reduced

aeration and non capillary porosity increased

water holding capacity relented

soil organic matter

total N and P

available N and P contents decreased. One percent of silt and clay contents (<0.05mm) were removed

could result in the decreases of 0.259 g/kg soil organic matter and 0.016 4 g/kg total N contents. Disturbances induced by farmers (i.e. cultivation of sandy grassland in the edge of farmland) was the main force of soil wind erosion and degradation. Two models of soil degradation process was put forward

namely

gradual degradation course and leap degradation course.