The soil moisture

which is mainly replenished by rainwater and snowmelt

is a crucial factor in maintaining the stability of the fragile ecosystem. Choosing a typical sand dune as study area in the hinterland of Gurbantonggut desert. In different terrain parts that contain the crest

the slope

and the foot of the natural dune

we laid 7 aluminum tubes by which the soil moisture content could be measured with a neutron probe

disposed 7 plant sample areas

7 iron poles which mark the wind-sand activity correspondingly

meanwhile

set up one weather station. With neutron probe

through field calibration and systemic study on soil moisture

plant sample area and wind-sand activity. The result shows that the space-time distribution of the soil moisture is closely related to terrain parts

the depth of soil

plant cover

rainfall

and the depth of accumulated snow. It is clear that the space distribution difference of the soil moisture. Generally

the soil moisture content of the inter-dune is higher than the dune crest

the lower slope higher than the upper slope. In the vertical direction

the soil moisture content of the surface layer is highest from late autumn to May of next year

the subsurface layer

from June to July

and the deep layer

after the August. In the time aspect

the change of soil moisture content shows that the soil moisture content is higher and the soil moisture content increases from March to April; the soil moisture content decreases rapidly from May to June; the soil moisture content is least from July to October; the soil moisture content is invariable except the soil moisture content of the surface layer in late autumn and winter.