In this paper,Siziwang Banner(41°10′～43°20′N,110°20′～112°55′E,1000～2100 m a.s.l.) in Ulanqab City in the
north Yinshan Mountain,Inner
Mongolia,is selected as the experimental area,where the terrain is dominated by hills with valleys and intermontane basins,the climate is extremely arid,the annual precipitation is about 300 mm but its spatiotemporal distribution is extremely asymmetrical,the annual evaporation is as high as 1600～2400 mm,strong winds occur frequently,and the natural vegetation is sparse.Wind-erosion desertification is extremely serious in the
north Yinshan Mountain,and the
wind-erosion amount is one of the important parameters in estimating soil erosion and land desertification.In this paper,the values of soil erosion in a typical farming-pasturing ecotone in Siziwang Banner are estimated based on the variation of topsoil grain sizes since recent years by using grain-size contrast method.Moreover,the soil wind-erosion amounts are derived based on the field-measured data of a strong sandstorm.After validating the estimated results,the soil wind-erosion amounts in the study area can be accurately calculated.After comparing the grain sizes of soils in a bare farmland and a common steppe,the soil erosion caused by traditional farming activities in the study area can be understood.The results reveal that the lost topsoil over the farmlands is dominated by soil grains with grain size < 0.05 mm,the average annual wind-erosion modulus is as high as 6214.7 t/km~2.The study results can provide the theoretical foundation for researching the farming activities in a protected way in arid areas.