Nitrogen isotopic composition of plant-soil in the Loess Plateau and its responding to environmental change
Nitrogen isotopic composition of plant-soil in the Loess Plateau and its responding to environmental change
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DOI：
10.1007/s11434-008-0442-y
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发表时间：
2009-01-01
影响因子：
--
通讯作者：
Wang Zheng
中科院分区：
文献类型：
--
作者：
Liu WeiGuo;Wang Zheng
土壤氮同位素作为自然系统中气候变化和氮素生物地球化学循环的指示器具有重要意义。本文通过对中国西北部干旱半干旱黄土高原现代生态系统中植物根系和表层土壤的氮含量和同位素组成的测定，研究了东亚季风气候条件下中国西北地区植物根系和土壤N-15增量随降水和温度梯度的变化趋势。研究区表层土壤的N-15值变化在-1.2a-5.8a欧罗度之间，而植物根部的N-15值变化在-5.1a-1.9a欧罗度之间。结果表明：(1)尽管植物根和土壤的同位素组成随气候梯度的变化趋势相似，但植物根与土壤之间存在明显的氮素差异，Delta N-15值变化在0.3~7.2a欧度之间，平均为4.1a欧度；(2)年平均降水量(MAP)是影响黄土高原植物-土壤氮同位素组成的主要因素，而Delta N-15值与MAT相关性较小，表明土壤氮同位素组成是潜在的环境变化示踪剂。
The nitrogen isotope of soil is of emerging significance as an indicator of climatic change and biogeochemical cycle of nitrogen in nature systems. In this paper, the nitrogen content and isotopic composition of modern ecosystems from arid and semiarid Loess Plateau in northwestern China, including plant roots and surface soil, were determined to investigate trends in delta N-15 variation of plant roots and soil along a precipitation and temperature gradient in northwestern China under the East Asian Monsoon climate condition. The delta N-15 values of surface soil from the study area vary from -1.2aEuro degrees to 5.8aEuro degrees but from -5.1aEuro degrees to 1.9aEuro degrees in the plant roots. Our results indicate that (1) although the isotopic compositions of both plant roots and surface soil change with a similar trend along the climate gradient, the apparent nitrogen difference between plant roots and soil existed, with Delta delta N-15 values ranging from 0.3aEuro degrees to 7.2aEuro degrees with average of 4.1aEuro degrees and (2) mean annual precipitation (MAP) is the dominant factor for isotopic composition of plant-soil nitrogen in the Loess Plateau, and the delta N-15 values are less correlated with MAT; we suggest that nitrogen isotopic composition of soil is a potential tracer for environmental changes.