Abstract: Soil moisture is an important index for sustainable utilization of desert steppe. Based on multi-point field observations of soil moisture and precipitation through two consecutive years of growing seasons, sustainability of soil moisture and spatio-temporal variation of soil moisture in soils different in land-use in the studied desert steppe was analyzed. Results show that soils different in land-use differed more sharply in soil moisture, in a dry year than in a wet year; soil moisture increased with the time in all the soils regardless of land use types in the dry years, but undulated in the wet year; the variation of soil moisture displayed a curve of three peaks and three valleys in the dry year in all the soils, but in wet year it was closely related to precipitation, and  soil moisture remained stable for quite a long time, from July to the next April; No matter whether in wet or in dry year, soil moisture was relatively high in alfalfa field and licorice field, lower in licorice-alfalfa mixed grassland and natural grassland, and the lowest in Caragana shrubland. The comparative analysis of the five soils different in land use, and spatio-temporal variations of their soil moisture and water supply and consumption may help better understand ecological process of the steppe on the landscape scale, which will be of some important significance to the effective use of soil moisture and soil and water conservation in desert steppe regions.

Key words: soil moisture, spatio-temporal variation, land use type, desert steppe region