Abstract Land use changes may modify ecohydrological processes in soil, altering groundwater quantity and quality in arid and semi-arid regions. The effects of land use change were well documented on flatlands, but the effect of rooting depth on groundwater recharge is poorly understood. This study is to evaluate how conversion of shallow-rooted to deep-rooted vegetation affects groundwater recharge at different landscape positions (i.e. tableland, upslope, midslope, and downslope). Two adjacent transects were selected for a paired plot design: one was covered with shallow-rooted perennial grasses and the other was planted with deep-rooted apple trees or apricot trees in 1990s. Soil cores (as deep as 13–25 m) were collected at each of the four landscape positions along the two transects for the determination of soil water contents, root distributions, and soil tritium contents. Groundwater recharge rates beneath shallow-rooted vegetation were determined from the tritium peak method, and that beneath deep-rooted vegetation were calculated by subtracting the annual soil water deficit from recharge rates beneath shallow-rooted vegetation. Results show that, there is no significant difference in groundwater recharge between the four landscape positions under shallow-rooted vegetation (p > 0.05); however, there is a substantial difference between different slope positions along the other transect (p

中文翻译：

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生根深度控制山坡上潜在的地下水补给

摘要 土地利用变化可能会改变土壤中的生态水文过程，改变干旱和半干旱地区地下水的数量和质量。土地利用变化对平地的影响已得到充分证明，但人们对生根深度对地下水补给的影响知之甚少。本研究旨在评估浅根植被向深根植被的转化如何影响不同景观位置（即台地、上坡、中坡和下坡）的地下水补给。选择相邻的两条样带进行配对样地设计：一个覆盖浅根多年生草，另一个在 1990 年代种植深根苹果树或杏树。在沿两条横断面的四个景观位置中的每一个处收集土壤核心（深达 13-25 m），用于测定土壤含水量，根分布和土壤氚含量。浅根植被下的地下水补给率由氚峰法确定，深根植被下的地下水补给率通过从浅根植被下的补给率中减去年度土壤水分亏缺来计算。结果表明，浅根植被下4个景观位置的地下水补给量无显着差异（p > 0.05）；然而，沿另一条断面的不同坡度位置之间存在显着差异（p 深根植被下的补给率是通过从浅根植被下的补给率中减去年度土壤水分亏缺来计算的。结果表明，浅根植被下4个景观位置的地下水补给量无显着差异（p > 0.05）；然而，沿另一条断面的不同坡度位置之间存在显着差异（p 深根植被下的补给率是通过从浅根植被下的补给率中减去年度土壤水分亏缺来计算的。结果表明，浅根植被下4个景观位置的地下水补给量无显着差异（p > 0.05）；然而，沿另一条断面的不同坡度位置之间存在显着差异（p