| Soil wind erosion is a primary factor affecting the development of economy and ecological security in the agro-pastoral ecotone of northern China. The region of North foot of Yinshan mountain in Inner Mongolia was selected for study in the thesis. Some primary factors that influence soil wind erosion in semiarid areas were qualitatively and quantitatively studied through meteorological data analysis, field investigations and wind tunnel simulation. At the same time, the conservation farming system of resisting wind erosion hazard was built on the basis of former research, household investigation and analysis of typical case. The main results of this paper can be showed as blow: View on the meteorological factor, Less precipitation and more strong wind from March to May determine the potential wind erosion risk in this area. The wind erosion hazard is often intensified by the poor vegetation cover and loosen surface soil due to the freezing and thawing over winter. The result of wind tunnel showed the rate of soil erosion increases with the increasing of wind velocity by the power function. The wind velocity of 18m/s is a significant point to aggravate the wind erosion. In the study area, the soil texture is coarse. The content of erosive particle (0.25-0.0 lmm) occupied about 30% or so and even 57% in somewhere. The coarse soil texture contributes to the occurring of wind erosion. The result of wind tunnel simulation test showed the rate of soil erosion by wind decreases with the increasing of soil moisture content by exponential function. The content of soil moisture equal 6% is turning point from severity to light for the rate of wind erosion. The dynamic change of factors influencing wind erosion varies under different land vegetation cover, (a) The soil texture of shrub and hilly forest land is coarser than farmland and nature grassland, (b) In general, the water content of surface soil for different vegetation types in wind erosive period behaved farmland protective plantation>nature grassland >farmland>hilly forest>shrub land, (c) The topsoil hardness in wind erosion period behaved farmland protective plantation>hilly forest land >natural grassland >shrub land >farmland. (d) The change of vegetation cover is distinct under different plant. The shrub, natural grassland and hilly forest can cover the land all through year. The degree of coverage behaved shrub>natural grassland>hilly forest. Comparing to the shrub, natural grassland and hilly forest, the coverage time of farmland is shortest and changed acutely at the different period. Especially in spring, the bare soil surface of farmland is vulnerable to wind erosion. Human activity is dominant factor contributing to the occurrence of wind erosion. The heavy population, increasing amount of livestock and the unreasonable land utilizing types are the important part of human activity affecting wind erosion. The technique of conservation farming system involved, the pasture and shrub are main vegetation type in vegetation restoration and construction. Crop residue should be left in the farmland to controlling the wind erosion. The conservation tillage and strip cropping should be also applied in the agricultural production. The developing pattern giving attention to both economic benefit and ecological benefit is dominant types in conservation farming system...
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