Tracing water uptake by jarrah (Eucalyptus marginata) trees using natural abundances of deuterium
Tracing water uptake by jarrah (Eucalyptus marginata) trees using natural abundances of deuterium
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DOI：
10.1007/s004680050052
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发表时间：
1996-11-01
影响因子：
2.3
通讯作者：
Gailitis, V
中科院分区：
文献类型：
--
作者：
Farrington, P;Turner, JV;Gailitis, V
在西澳大利亚州的3个不同土壤和地下水位深度的地点，测定了树枝汁液、土壤、降雨和地下水中δ（2）H含量的季节变化，以确定黄桉树（Eucalyptus marginata）树木可利用的水源。在冬季和春季的树木的水分吸收的主要贡献者是储存在土壤表层的水分主要是冬季降雨补充。随着夏季干旱的开始，贾拉变得更加依赖于更深层次的水。没有明确的证据表明jarrah可以从超过14米深的地下水中取水。使用稳定同位素确定深层红土中树木的水源受到大部分非饱和区和地下水中氘分布均匀的阻碍。秋季降雨输入后，枝条内边材水δ（2）H值对深层沙上层δ（2）H值的变化响应有限。阻尼响应与一年中大多数事件中降雨的δ（2）H组成的微小变化以及从土壤剖面不同位置提取的水在树中的混合有关。
Seasonal change in the delta(2)H content of water from twig sap, soil, rainfall and groundwater were measured to determine the water sources accessed by jarrah (Eucalyptus marginata) trees at three sites in Western Australia with differing soils and depths to water table. During winter and spring the main contributor to the water uptake of the trees was stored water in the surface layers of the soil replenished by predominantly winter rainfall. With the onset of summer drought jarrah became more reliant on water from deeper down the profile. There was no clear evidence that jarrah could tap water from groundwater more than 14 m deep in deep sands. Defining the source of water for trees in deep lateritic soils using stable isotopes is hampered by the uniform deuterium profiles down most of the unsaturated zone and into the groundwater. There was a limited response in the delta(2)H values of sapwater in twigs to changes in the delta(2)H of the upper layers of the deep sand following input of rainfall in autumn. The damped response was related to the small variation in the delta(2)H composition of rainfall in most events during the year and the mixing in the tree of water extracted from different locations in the soil profile.