中文摘要：

黄土区人工经济林普遍出现利用性土壤干层,制约着植被的恢复与重建。为了准确计算黄土半干旱区密植高产枣林（Ziziphus jujube Mill.）深层土壤（2 m以下）水分消耗量,采用根钻法（洛阳铲）分层获得从地表到细根分布最大深度范围内的土壤含水率。结果表明：枣林深层土壤水分消耗是一个逐渐加深、逐渐向下的过程。2、4、9和12 a生枣林深层土壤水分消耗量分别为0、29.6、149.9和155.7 mm,可再供水量分别为203.7、167.7、35.5和29.7 mm;枣林生长第9年后,2-4 m土层几乎没有可利用的水分,现有降水和滴灌已经不能满足枣树的耗水需求,枣林吸收土壤水分有向深处延伸的趋势。以降水入渗最大深度为上界、细根分布最大深度为下界计算的深层土壤水分消耗量,能更准确地评估林地利用性土壤干层的程度和深度。

英文摘要：

Soil dry layer has occurred widely in artificial economic forest in Loess region, which constrained vegetation restoration and reconstruction. In order to investigate deep soil depletion（ below2 m） in densely planted jujube（ Ziziphus jujube Mill.） orchard,soil coring method（ Luoyang shovel）was used to get soil water content from surface to the maximum fine rooting depth at 0. 2 m soil interval.The results showed that root water uptake had a tendency to extend gradually deep,deep soil water depletion was 0,29. 6,149. 9 and 155. 7 mm in 2,4,9 and 12-year-old jujube plantation,deep soil water supply was 203. 7,167. 7,35. 5 and 29. 7 mm,respectively,annual deep soil water depletion accounted for 0,2. 3%,5. 1% and 3. 9% of annual soil water supply. There was almost no available water in 2 - 4 m soil layer when the jujube plantation developed for 9 years. Jujube water requirement could not be met by the existing rainfall and drip irrigation amount. Soil dry layer extent and depth can be evaluated more accurately with the maximum rainfall infiltration depth and maximum fine rooting depth as upper and lower boundaries. Soil water content could be increased through water catchment,water conservation and water supplement,which played an important role in alleviating jujube plantation deep soil drying.