Abstract: This paper studied the horizontal and vertical variation and distribution of soil moisture and total soluble salt contents on the reservoir dam of Sanjiaozhou plain in Dawa of Liaoning at different slope aspect and position and different soil depth. As compared with soil moisture content, soil total soluble salt content had a greater variability. Both the soil moisture content and the soil total soluble salt content showed a moderate variability, and their variability was tended to be unanimous. The average soil total soluble salt content was higher on south-facing slope than on north-facing slope, while the average soil moisture content was in adverse. The average total soluble salt content in different soil layers was decreased in the order of middle layer > lower layer > surface layer, while the average soil moisture content was increased with increasing depth. There was no significant difference in the soil total soluble salt content among different slope positions. The average soil moisture content was higher on lower slope than on upper and middle slopes, but had no significant difference between upper and middle slopes. These results provided a reference for the control of saline-alkali soil and the rehabilitation of vegetation on the reservoir dam in Liaohe Delta plain and its surrounding areas.

Key words: saline-alkali soil, community structure, clone library, diversity, dominant populations.