Chin J Plant Ecol ›› 2009, Vol. 33 ›› Issue (6): 1101-1111.DOI: 10.3773/j.issn.1005-264x.2009.06.010

• Original article • Previous Articles     Next Articles

VEGETATION CARRYING CAPACITY BASED ON SOIL WATER ON TYPICAL SLOPES IN THE DIEDIEGOU SMALL WATERSHED OF LIUPAN MOUNTAINS, NORTHWESTERN CHINA

LIU Jian-Li1,2, WANG Yan-Hui1,*(), YU Peng-Tao1, CHENG Li-Li3, XIONG Wei1, XU Li-Hong1, Du A-Peng1   

  1. 1 Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China
    2 Key Laboratory of Soil and Water Conservation and Combating Desertification, Ministry of Education, College of Water and Soil Conservation, Beijing Forestry University, Beijing 100083, China
    3 Institute of Forestry and Pomology, Beijing Academy of Agricultural and Forestry Sciences, Beijing 100093, China
  • Received:2009-05-07 Accepted:2009-08-03 Online:2009-05-07 Published:2021-04-29
  • Contact: WANG Yan-Hui

Abstract:

Aims Soil water is the main limiting factor for vegetation, and it mainly comes from precipitation in the Diediegou small watershed in the Liupan Mountains, northwestern China, where the structure of slope vegetation is usually closely related with the amount of precipitation. Our objectives were to develop a method for estimating vegetation carrying capacity (VCC) on sites based on water balance and to evaluate variation of VCC along typical slopes, for guiding the restoration and management of vegetation on similar slopes.

Methods We established nine plots along two typical slopes of natural grassland and larch (Larix principis-rupprechti) plantation, measured leaf area index (LAI) every 15 days and continuously monitored all water fluxes and soil water dynamics. After analyzing plot water balance, we determined the relationships among evapotranspiration (ET), LAI and precipitation to estimate VCC based on growing season precipitation and calculated the variation of VCC along slopes.

Important findings Our mathematical models for determining VCC (expressed as the maximal LAI) based on precipitation amount (P, mm) in growing season (April-October) were LAItree=exp ((0.773 1×P-186.12)/146.46) for the larch stand on the shady slope and LAIgrass=exp ((0.511 2×P-345.93)/227.89) for the grassland on the sunny slope. The VCC of larch stands on the shady slope increased from upper slope (1.45) to middle slope (4.83) and then stabilized between 3.0 and 3.3. For grassland on the sunny slope, VCC increased from upper slope (0.37) to middle slope (0.46) and then stabilized between 0.41 and 0.47. Measured values ofLAIwere close to those of simulated VCC, supporting the rationality of our method and the result. Using LAI as an index expressing VCC, which is mainly determined by soil water in dryland regions, is a new method for calculating VCC for slopes where precipitation water is redistributed in the forms of runoff and interflow.

Key words: Liupan Mountains, slope, soil water, carrying capacity, vegetation restoration, leaf area index (LAI)