中文摘要：

采用Trime-IPH管式TDR系统,对黄土丘陵区2龄、6龄、10龄、15龄旱作红枣林（Ziziphus jujube cv.Junzao）生育期内土壤剖面含水率进行连续监测,以探讨旱作枣林土壤含水率随树龄的变化特征。结果表明：2014年0.4 m以下土层、2015年0.6 m以下土层土壤含水率随红枣林树龄增加,呈减少趋势。2014年常态年红枣林土壤水分随生育期变化整体呈上升趋势;2015年干旱年红枣林土壤水分随生育期变化整体呈下降趋势。各树龄红枣林0-0.6 m土层土壤水分波动较大;〉0.6-1.8 m土层干旱年时形成季节性低湿层;〉1.8-3.0 m土层土壤水分呈常年低湿状态。持续干旱条件下,2龄、6龄红枣林雨后7 d土壤水分损失率分别为20%和19%,显著高于10龄、15龄红枣林土壤水分损失率（13%和18%）,而雨后18 d,2龄、6龄红枣林土壤水分损失率增速缓和,10龄、15龄红枣林土壤水分损失率呈显著上升趋势。干旱年时红枣林在开花坐果期和果实膨大期需增加水分管理措施以有效降低枣树自身奢侈性耗水和非生产性耗水,实现红枣林可持续发展。

英文摘要：

Jujube is a kind of perennial fruit tree in arid and semi-arid areas in central and eastern Asia. Since the initiation of the large-scale ecological rehabilitation project（known as ＂Grain for Green＂ project） by the Chinese central government in 1999, the area of jujube orchards has been increased rapidly in the loess hilly region mainly for conserving soil and water and raising economic benefits. Here we investigated the variation of root-zone soil water with a range of stand ages（2, 6, 10 and 15 years） in a rain-fed jujube（Ziziphus Jujube Mill. cv. Lizao） plantation in Qingjian County, Shaanxi Province（37°15′N, 118°18′E）. A portable time domain reflectometry（TDR） system（IMKO, Ettlingen, Germany） was used to monitor the soil profile water in study sites. Sixteen tubes with the length of 3 m were installed at a distance of 0.3 m from the representative tree trunk for each stand in October, 2013. Soil water content was measured once every 2 weeks from May to October in 2014 and 2015. The results showed that： 1） During the growth period of 2014, soil water content in the 2- and 6-year-old jujube trees increased first with depth and peaked in the 0.6 m soil layer, and then decreased gradually with depth, while the peak position of soil water content in 10- and 15-year-old jujube trees were both in the 0.4 m soil layer. However, the peak position of soil water content in 2015 was 0.2 m deeper than that in 2014 in all study sites due to serious drought. There were different monthly dynamics of soil water content in study sites during the growth period between 2014 and 2015. In 2014, soil water content was the lowest in June（from May to October）, which was increased greatly in August and reached the maximum value in October, whereas there was declining tendency of soil water content from May to September in 2015. 2） The precipitation was relatively abundant in the period from July to September in the study area, which accounted for 70% of the rainfall during the jujube growth