Journal of Geographical Sciences ›› 2009, Vol. 19 ›› Issue (6): 707-718.doi: 10.1007/s11442-009-0707-7

• Climate and Environmental Change • Previous Articles     Next Articles

Soil moisture of different vegetation types on the Loess Plateau

WANG Zhiqiang1, LIU Baoyuan2, ZHANG Yan2   

  1. 1. State Key Laboratory of Earth Surface Processes and Resource Ecology, School of Geography, Beijing Normal University, Beijing 100875, China|
    2. Key Laboratory of Soil and Water Conservation &|Desertification Combat, Beijing Forestry University, Ministry of Education, Beijing 100083, China
  • Received:2008-12-29 Revised:2009-04-15 Online:2009-12-25 Published:2010-09-18
  • Supported by:

    National Key Basic Research Special Foundation Project of China, No.2007CB407204; National Natural Science Foundation of China, No.40471082

Abstract:

Water stored in deep loess soil is one of the most important resources regulating vegetation growth in the semi-arid area of the Loess Plateau, but planted shrub and forest often disrupt the natural water cycle and in turn influence plant growth. The purpose of this study was to examine the effects of main vegetation types on soil moisture and its inter- annual change. Soil moisture in 0–10 m depth of six vegetation types, i.e., crop, grass, planted shrub of caragana, planted forests of arborvitae, pine and the mixture of pine and arborvitae were measured in 2001, 2005 and 2006. Soil moisture in about 0–3 m of cropland and about 0–2 m of other vegetation types varied inter-annually dependent on annual precipitation, but was stable inter-annually below these depths. In 0–2 m, soil moisture of cropland was significantly greater than those of all other vegetation types, and there were no significant differences among other vegetation types. In 2–10 m, there was no significant moisture difference between cropland and grassland, but the soil moistures under both of them were significantly higher than those of planted shrub and forests. The planted shrub and forests had depleted soil moisture below 2 m to or near permanent wilting point, and there were no significant moisture differences among forest types. The soil moisture of caragana shrub was significantly lower than those of forests, but the absolute difference was very small. The results of this study implicated that the planted shrub and forests had depleted deep soil moisture to the lowest limits to which they could extract and they lived mainly on present year precipitation for transpiration.

Key words: Loess Plateau, vegetation type, deep soil profile, soil moisture, inter-annual change