黄土高原干旱阳坡微地形土壤水分特征研究

Soil Moisture Characteristics on Microrelief of Dry South-slope on the Loess Plateau

黄土高原地区坡面内地表的起伏形成微地形,利用其土壤含水量的差异来提高植被成活率已经成为黄土高原生态恢复建设的重要方向。采用探针式TDR对陕西省吴起县合家沟流域内的微地形及其相应原状坡的土壤含水量进行测定。结果表明,微地形对土壤含水量有显著影响,阳坡各微地形土壤水分顺序为:塌陷>切沟底>缓台>浅沟底>原状坡>陡坎。0—20cm土层土壤水分变异系数最大的是切沟底为0.405,最小的是缓台仅0.226,阴坡原状坡各层的变异系数均小于阳坡的微地形。最后指出黄土高原地区植被恢复建设时,在按传统立地类型划分原则所确定的植被恢复单元内,还应该按照微地形的水分特征有区别地配置植被类型。

On the loess plateau,fluctuating land surface forms microrelief.Using the difference of soil moisture content on microrelief to improve the survival rate of vegetation has become an important method in ecological restoration and construction.Using probe-type TDR,we measure the soil water content on microrelief and the corresponding original slope in Hejia valley,Wuqi County,Shaanxi Province.Results show that microrelief has a significant impact on soil moisture content.In terms of soil water on sunny slope,landform units may be ranked in the descendant order of collapse,gully bottom,platform,shallow gully bottom,original slope,and scarp.The variation coefficient of soil water （0—20 cm surface soil） at gully bottom is the biggest （0.405） and on platform,the smallest （0.226）.The variation coefficient of soil water on shady original slope is less than that on microrelief of sunny slope.Therefore,in the vegetation restoration of the Loess Plateau,we should configure vegetation types in the vegetation restoration units determined by the traditional principles according to the soil water characteristic on microrelief.