在陕北黄土区安塞县纸坊沟小流域,选择不同林龄的狼牙刺地块,对其土壤水分作了动态观测,并以柠条地和撂荒地为对照。分析研究得出如下结论:①在土层足够深的地块上,天然灌木狼牙刺年蒸散量约为590mm,单株平均耗水量约85mm。强烈耗水期是5月中旬至7月底,8月底土壤水分达到最低值,9月份以后开始恢复;②狼牙刺地土壤水分活跃层在0-2.5m之间,土壤水分的消耗强度随深度的增加而下降;③狼牙刺地干层超过10m,比同龄的柠条土壤干层(8m)深,在两个生长季中,干层没有进一步发展。

Based on measurement of the monthly soil moisture content in 2002 by choosing the different age's S.viciifolia Hance plots in the hilly and gully area of northern Shaanxi province, and(making fallow land and Caraganar land as a contrast,the following conclusions can be drawn from this paper: 1)The annual evapotranspiration of the 5. viciifolia Hance shrub in the sufficiently deep layer of the plots is 590mm and the mean water consumption of individual plant is about 85mm;water consumption is intense from May to July,soil moisture is the least in August and increases in September. 2)The soil moisture in the profile between 0-2.5m is active, the intensity of soil moisture consumption weakens with the increase of soil depth. 3)The depth of the "dry soil profile" is more than 10m that is deeper than the Caraganar's, but it didn't develop further during the two years.