Soil wind erosion is one of the most serious environmental and socio economic problems in many semiarid ecosystems of the world. Donggou small watershed of the Luanhe River source area (41°31′36″-41°33′56″N, 116°06′06″-116°11′50″E, 1560-1960?m a.s.l.) is one of the prototype mixed pasture agriculture frost ecosystems in the North China, where the soil wind erosion is developing rapidly and receiving widespread attention. The properties of the soils, which are influenced by wind erosion, are very important information for the wind erosion prediction and conservation. Using the detailed ground based investigations of the household livelihoods, land use, environmental characteristics and diagnostic soil characteristics of Donggou small watershed, this paper analyses the wind erosion properties of the Hap Ustic Isohumisols (or dark chestnut soil) in the areas with different wind erosion intensities. The results show that: (1) During winter and spring, Donggou small watershed has very strong wind (cold wave) and little precipitation, the soil is in drying friable state, and soil texture is sandy, these natural environmental factors have provided the material resource and kinetic energy for the wind erosion processes. For traditional farming intensity is becoming increasingly high, the livestock capacity on the grassland and demand for the fuel wood is becoming more day by day.
These anthropogenic factors have been the trigger driving force for the wind erosion processes. (2) For drying friable surface soil, which has lost the protective cover of vegetation, the fine sand (0.10- 0.05?mm) and very fine sand (0.05-0.01 mm) are carried away first by suspension and saltation. But the coarse sand (2.00-0.25 mm) in the surface soil is relative nonerodible particles. (3) A quantitative index was used to estimate the wind erosion intensity in the study area, i.e. SWEI = CS/EF , where CS is the content of the coarse sand in the surface soil, EF is the content of the fine sand and very fine sand in the surface soil. In the distribution areas of the Hap Ustic Isohumisols, the SWEI ≤2.0; in the distribution areas of weakly eroded soils, the SWEI ≥3.0; in the distribution areas of very strong eroded soils, the SWEI ≥9.0; But in the wind deposition areas, the SWEI ≤1.5.