Water Balance Simulation in SPAC Systems of Slope Lands Covered with Typical Vegetations on Loess Plateau

Abstract:

A numerical model, soil-water-atmosphere-plant model (SWAP), was applied to simulate dynamics of soil moisture and soilwater balance in three kinds of land use patterns, including cropland with mung bean, Stipa bungeana grassland and alfalfa grassland, based on field observations. The predicted values of soil moisture and soil water storage had obviously consistent with the measured values. The water input on Stipa bungeana grassland was roughly equal to the output. The water output on alfalfa grassland was 1.38 times of that on cropland, and the evapotranspiration of alfalfa was 3.88 times of that on cropland with mung bean, which was the main reason causing soil water deficit on alfalfa grassland. So conversion of farmland to forest and grassland regeneration will increase the output of water in the SPAC system, if there is a great deal of water consumption by vegetation community, it will lead to soil desiccation.