Abstract:

Based on the balance between water supply (available soil moisture) of soil and water consumption by vegetation transpiration and soil evaporation, this study focus on determining the suitable vegetation coverage in the slope of loess area where carried on the policy of returning farmland to forests and grass land. Loess area, Ji County in Shanxi Province, was taken as a case study. According to a long-term monitoring in the research area, the following parameters, available soil water content, the intercepting rate, runoff coefficient, soil water content, soil evaporation and evapotranspiration were get in the main forest lands. Based on all the above variables, the suitable vegetation coverage of the main species (including Pinus tabulaeformis, Robinia psedoacacia, shrub and grass) in the research area was calculated using the model developed. The results will provide the theoretical foundation for the project of returning farmland to forests and grassland and other forestry ecological engineering projects on the designing of efficient spatial distribution and stable stand structure for protection forest.

Key words: vegetation coverage, soil water balance, loess area