Soil water dynamics around a tree on a hillslope with or without rainwater supplied by stemflow
Soil water dynamics around a tree on a hillslope with or without rainwater supplied by stemflow
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DOI：
10.1029/2010wr009856
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发表时间：
2011-02
影响因子：
5.4
通讯作者：
W. Liang;K. Kosugi;T. Mizuyama
中科院分区：
文献类型：
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作者：
W. Liang;K. Kosugi;T. Mizuyama
树木可以将降雨分为穿透雨和树干茎流（SF），使水在树基周围形成漏斗，并可以优先将雨水转移到土壤层中，使水在树根周围形成漏斗。为了确定每一个对土壤水分动态的影响，我们比较了土壤水分动态周围的一棵树在山坡上2年的实地观察之前（SF期间）和之后（非SF期间）拦截树干茎流的树木。此外，使用不同的染料示踪剂进行了两个喷洒实验，分别识别来自穿透雨和茎流的入渗途径。结果表明，在SF期，土壤含水量变化不规则，土壤贮水量高，且在树下坡区有明显的饱和带发育，这与树干茎流集中在树下坡侧有关。虽然在非SF期间土壤水分动态的剧烈变化消失，但也观察到不对称的土壤水分响应模式，这主要归因于根诱导的旁路流。在SF和非SF期间，以下坡区域为重点，土壤-基岩界面处的饱和区产生频率从58%降低到16%，但旁通流发生频率变化不大。在SF和非SF期间，在树下的土壤-基岩界面处的饱和区生成表明，树木是降雨渗透的关键位置，即使在没有茎流供应的条件下，也应仔细考虑树木引起的饱和区生成。
A tree can partition rainfall into throughfall and stemflow (SF), causing water to be funneled around the tree base, and can preferentially divert rainwater in soil layers, causing water to be funneled around tree roots. To determine the effects of each on soil water dynamics, we compared soil water dynamics around a tree on a hillslope on the basis of 2 years of field observations before (SF period) and after (non‐SF period) intercepting the stemflow of the tree. Additionally, two sprinkling experiments were conducted using different dye tracers to separately indentify infiltration pathways derived from throughfall and stemflow. The observation results in the SF period showed irregular variations in soil water content, high soil water storage, and significant saturated zone development in the downslope region from the tree, which were attributed to stemflow concentrated on the downslope side of the tree. Although dramatic variations in soil water dynamics disappeared in the non‐SF period, asymmetrical soil water response patterns were also observed, which were mainly attributed to root‐induced bypass flow. Focusing on the downslope region in the SF and non‐SF periods, the frequency of saturated zone generation at the soil‐bedrock interface decreased from 58% to 16%, but the frequency of bypass flow occurrence varied little. Saturated zone generation at the soil‐bedrock interface underneath the tree in both the SF and non‐SF periods suggests that trees are key locations for rainfall infiltration and that tree‐induced saturated zone generation should be considered carefully, even in conditions without stemflow supply.