植物生态学报 ›› 2022, Vol. 46 ›› Issue (12): 1523-1536.DOI: 10.17521/cjpe.2021.0427

所属专题: 稳定同位素生态学 碳水能量通量

• 综述 • 上一篇    下一篇

土壤CO2通量梯度观测技术和方法的理论、假设与应用进展

王晶苑1, 魏杰1,*(), 温学发1,2   

  1. 1中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室, 北京 100101
    2中国科学院大学资源与环境学院, 北京 100190
  • 收稿日期:2021-11-22 接受日期:2022-05-21 出版日期:2022-12-20 发布日期:2023-01-13
  • 通讯作者: *魏杰(weijie@igsnrr.ac.cn)
  • 基金资助:
    国家自然科学基金(41830860);国家自然科学基金(42077302)

Progress in the theory, hypothesis and application of the methods measuring soil CO2 flux gradient

WANG Jing-Yuan1, WEI Jie1,*(), WEN Xue-Fa1,2   

  1. 1Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
    2College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China
  • Received:2021-11-22 Accepted:2022-05-21 Online:2022-12-20 Published:2023-01-13
  • Contact: *WEI Jie(weijie@igsnrr.ac.cn)
  • Supported by:
    National Natural Science Foundation of China(41830860);National Natural Science Foundation of China(42077302)

摘要:

土壤呼吸主要包括大气-土壤界面CO2释放量和土壤中CO2储存量变化两部分, 深入理解土壤CO2的产生和迁移过程是全面认识陆地生态系统碳循环的基础。通量梯度法是基于测量扩散驱动的CO2浓度梯度和扩散系数计算CO2通量的方法, 依据菲克第一定律可以计算出不同深度土壤CO2及其稳定碳同位素组成(δ13C)通量, 进而得到土壤CO2释放量和不同深度土壤CO2储存量。地下土壤CO2浓度(13CO212CO2浓度)主要受孔隙曲折度、根分布深度、微生物活性和土壤总CO2产生量控制。地下CO2传输过程受不同深度CO2浓度、孔隙度和含水量等的共同控制, 上述土壤理化性质和生物因素是土壤通量梯度法应用过程的关键影响因素, 直接决定了CO2及其δ13C通量计算的精度和准确度。通量梯度法是箱式法的有益补充, 可以明确不同深度土壤CO2产生和运移过程以及对土壤CO2释放量和储存量的影响, 阐明不同深度土壤对CO2排放的相对贡献, 揭示其环境和物理控制机制。

关键词: 通量梯度法, CO2浓度梯度, 扩散系数, CO2通量, δ13C通量

Abstract:

Soil respiration is mainly composed of the CO2 released from atmosphere-soil interface and change of CO2 stored in the soil. Understanding the production and migration of CO2 in the soil is essential for measuring the carbon cycle in terrestrial ecosystems. The flux gradient method calculates soil CO2 flux by measuring the diffusion-driven CO2 concentration gradient and diffusion coefficient. The flux of soil CO2 and its stable carbon isotopes composition (δ13C) at different depths can be calculated based on Fickʼs law. The amount of CO2 released from soil and the amount of CO2 stored in different soil layers can thus be measured. The underground soil CO2 (13CO2 and 12CO2) concentration is mainly controlled by pore tortuosity, the depth of root distribution, microbial activity and total soil CO2 production. The underground CO2 transmission process is mainly controlled by the CO2 concentrations, porosity and water content at different depths of the soil. These physical, chemical and biological features of the soil are key factors affecting the application of the soil flux gradient method, and directly determine the precision and accuracy of soil CO2 and its δ13C flux calculation. The gradient method is a useful complement to the chamber method, which can clarify the process of production and migration of soil CO2 at different depths and thus the impacts on the release and storage of soil CO2, elucidating the contribution of soils at different depths to CO2 release and uncovering the underlying environmental and physical mechanisms.

Key words: flux gradient method, CO2 concentration gradient, diffusion coefficient, CO2 flux, δ13C flux