Management of Soil Moisture for Desert Steppe Vegetation Rehabilitation in Western Loess Plateau

The study compared soil moisture in 0~2 m layer under the three representative natural zonal vegetations in the Desert Steppe of Lanzhou area,they are the herbage of Stipa breviflora,the shrubs of S.passerina Bunge and C.roborovski;at the same time determined the roots distribution of natural herbage and shrub vegetation.The study results showed that the natural vegetation affected soil moisture mainly in the soil layer of 0~1m,from which down soil moisture reduced,then came to the stabilization when the soil depth became certain deep.The mean soil moisture in soil layer of 0~1m under Stipa breviflora herbage was higher than that of under S.passerina Bunge and C.roborovski shrubs,and respectively with a increase of 1.08% and 1.21%.Below 1 m,the dynamic range of soil moisture was the highest under shrubs of S.passerina Bung,the lowest under the shrubs of C.roborovski. After analyzing the effect of natural vegetation on soil moisture in the Desert Steppe of Lanzhou area,the study had given some advice about vegetation rehabilitation of this area.