Abstract:

The water dynamics in soil with different leaf area indexes and the soil water deficit value in the prerequisite to assure the plant survival were simulated and calculated using the dynamical soil water model based on the water balance theory, the characteristics of the environment and the physiological ecology of the plants in the Ulan Buh Desert, and the soil water carrying capacity of vegetation in the area was estimated. The results showed that the proportion of the soil evaporation was more than 60% of the precipitation in wandering and semifixed sands, while it was 44.8% in fixed sand. When the leaf area index was less than 1.7 m²·m－2, the soil water deficit remained in a lower level, while when the leaf area index continuously increased, the soil water deficit increased rapidly. It was concluded that the leaf area index of the soil water carrying capacity of vegetation was 1.7 m²·m－2in this area.

Key words: Ulan Buh Desert, soil water deficit, soil water carrying capacity of vegetation, leaf area index