| 元阳梯田水源区土壤水氢氧同位素特征 |
| 摘要点击 2839 全文点击 1342 投稿时间：2014-12-14 修订日期：2015-01-18 |
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| 中文关键词 元阳梯田 土壤水 蒸发 森林 氢氧同位素 |
| 英文关键词 Yuanyang terrace soil water evaporation forest hydrogen and oxygen isotopes |
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| 中文摘要 |
| 稳定同位素技术为土壤水的运移研究提供了一种全新的研究手段. 通过对元阳梯田水源区降水及其4种典型植被类型(乔木林、灌木林、荒草地和无林地)下0~100 cm剖面土壤水进行采样和氢氧稳定同位素的分析测定,研究了该区不同深度层次上土壤水的稳定同位素特征. 结果表明,元阳梯田水源区的大气降水线方程为δD=6.8384δ18O-5.6921(R2=0.8787,n=20),其斜率和截距均小于全球大气降水线. 4种典型植被类型下的土壤水氢氧稳定同位素值均落于当地大气降水线下侧,且其表层土壤剖面上的同位素值波动变化幅度较大. 随着土层深度的增加,δ18O值的波动变化越来越小,尤其以80~100 cm土层体现的最为明显. 乔木林和荒草地两种林分类型整体上深层土壤水中的δ18O值要偏高于表层土壤,而灌木林和无林地则恰恰相反. |
| 英文摘要 |
| Stable isotope techniques provide a new approach to study soil water movement. The precipitation and the soil water from 0 to 100 cm soil layer in 4 kinds of typical vegetation types (forest, shrub forest, grassland and non-forest land) over the water source area of Yuanyang terrace were sampled, and their isotope compositions were analyzed, aimed to understand the characteristics of stable isotopes in different depth of the soil water. The results showed that the meteoric water line in the water source area of Yuanyang terrace was δD=6.8384δ18O-5.6921(R2=0.8787, n=20), the slope and intercept were less than the global atmospheric precipitation. The hydrogen and oxygen stable isotopes in the soil water of the 4 kinds of typical types was lower than the local meteoric water line side and the fluctuation of isotope value on surface soil profile was greater. With the increasing soil depth, the fluctuation of delta 18O value was smaller and smaller, especially in the 80-100 cm soil layer which was the most obvious. The delta 18O values of the deep soil water in forest and grassland were higher than that in the surface soil, while it was on the contrary in shrub forest and non-forest land. |
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