Root systems play an important role in the hydrological cycle by largely controlling water fluxes to the atmosphere and groundwater. Root distribution characteristic determines its water use strategy and has a direct effect on soil water depletion. In water-limited arid and semiarid regions, soil water is a critical factor affecting plant growth that may determine plant distribution pattern. The relationships between soil water and plant have been reported for a wide range. However, very limited information about the forest deep root and deep soil water has been reported. Little study has focused on the stand density effect on jujube plantation. Our study was conducted to determine the spatial distribution of fine root and soil profile water characteristic of the 12-year-old drip irrigated densely jujube plantation (Ziziphus jujube Mill.) with 2.4 m between trees and 2.4 m between tree rows, widely jujube plantation as control was not drip irrigated with 4 m between trees and 5 m between tree rows in the loess hilly region. Soil core method (Luoyang shovel) was used to obtain fine roots from 5 different horizontal positions in 0-5.4 m in densely jujube plantation and 4 different horizontal positions in 0-10.4 m in widely jujube plantation respectively, and soil water content was observed in 0-10.4 m at 0.2 m interval in the two jujube plantations. The results showed that: 1) Fine root dry weight density was decreased with soil depth and more than 50%of fine roots were concentrated in 0-0.8 m soil layer which was the dense root layer. It was 52.3%and 57.7% in the top four layers in densely and widely jujube plantations respectively. There were significant differences in the fine root dry weight density among the top four soil layers in the same sampling position, and no significant differences were observed among different horizontal positions. 2) Fine root dry weight density was increased with the increasing of the stand density, but the maximum fine root depth showed opposite tendency. The maximum fine root depth extended 5 m and the total fine root dry weight density was 2319.38 g/m3 in densely jujube plantation, while it was 10 m and 1969.06 g/m3 in widely jujube plantation respectively. When the soil water in the upper layer could not provide the jujube growth demand, root had to gradually move to deeper layer to absorb soil water. 3) The average of soil water content in 0~10.4 m was 8.34%and 6.68%in densely and widely jujube plantation respectively. Soil water content was greater in densely jujube plantation with drip irrigation than in widely jujube plantation. The low soil water content zone was concentrated in 1.6~3.0 m soil layer in densely jujube plantation while it was 2.2~4.6 m in widely jujube plantation. The soil depth of low soil water content zone moved up 1.6 m in densely jujube plantation than widely jujube plantation. Drip irrigation and densely plantation had an important effect on artificial forest root and soil water, drip irrigation could reduce the maximum rooting depth, and roots were shallower in densely jujube plantation which can alleviate deep soil water depletion.% 为明确黄土丘陵区滴灌密植枣林（Ziziphus jujube Mill.)细根（直径＜2 mm）及土壤水分的空间分布特征，以无滴灌稀植枣林为对照，利用根钻法（洛阳铲）分别获得12 a生密植枣林地0～5.4 m和12 a生稀植枣林地0～10.4 m土层的细根干重密度，及0～10.4 m的土壤水分。结果表明：枣林细根干重密度随土层深度的增加而减少，50%以上的细根集中分布在0～0.8 m的土层中，该土层为根系密集层。密植枣林的细根干重密度较稀植枣林高，而细根最大分布深度却相反，密植枣林细根最大分布深度为5 m，稀植枣林为10 m。密植枣林土壤水分低值区的土层达3.0 m，稀植枣林延伸到4.6 m。该研究表明滴灌密植对枣林根系分布及土壤水分有显著影响，滴灌可减短枣林细根最大分布深度，滴灌条件下密植枣林整体根系较浅，有利于减轻深层土壤水分消耗。
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