稳定同位素分析技术在农田生态系统土壤碳循环中的应用

加强农田土壤碳动态变化过程和调控机制的认识，对于深入认识陆地生态系统碳循环过程和准确估算全球碳平衡有着重要意义。稳定碳同位素作为一种天然的示踪物，较放射性同位素具有安全、无污染、易控制的优点，在农田生态系统土壤碳循环研究中得到广泛应用。采用稳定碳同位素自然丰度法或示踪技术，研究农田生态系统大气一作物一土壤连续体中碳同位素变化规律，能够较真实地反映土壤有机碳的累积及其分解转化过程。本文概述了农田生态系统碳素循环诸过程中的^13同位素分馏机制，稳定碳同位素质谱分析技术的基本原理与方法，以及近年稳定碳同位素自然丰度或示踪法在农田生态系统土壤碳循环研究中的一些应用实例，并针对当前研究存在的问题进行总结。

Stable Isotope Technique in the Soil Carbon Cycling Research of Agricultural Ecosystems

The agricultural soil carbon dynamic process and its regulatory mechanism helps inform better understanding of terrestrial carbon cycle processes and global carbon balance estimates. Stable carbon isotope as a natural tracer has many advantages over radioisotope techniques such as safety, no pollution and high controlability, and has been widely used in the soil carbon cycling research in agricultural ecosystems. Investigation of the carbon isotopic variation in the atmosphere-crop-soil system by using natural abundance or tracer technique of stable carbon isotope contributes to revealing soil organic carbon decomposition, transformation and other dynamic processes. The carbon cycling processes and the related ^13C isotopic fractionation were introduced. The theory and methods about the stable carbon isotope analysis and its applications in the research of soil carbon cycling of agricultural ecosystems were reviewed. Finally, comprehensive summations of the problem existing in current research in conjunction with the prospects of the future research on soil carbon cycling were proposed.