摘要
土壤呼吸中根系呼吸和微生物呼吸的区分在研究生态系统碳循环和土壤碳储量时具有重要意义。较系统地介绍了各种区分方法,主要包括成分综合法、生物量外推法、根去除法、同位素标记法等。现国内研究中使用生物量外推法较多,但其相关性较差。根去除法又可分为根移除法、挖沟隔离法和林隙法,由于是就地测定,其数据可信度较高。同位素标记法包括脉冲标记法和连续标记法,该方法避免了大的干扰,数据较准确,缺点在于设备复杂、操作困难、分析费用高。同时对各种方法的原理和应用进行了介绍。
The contribution of root respiration to total soil respiration is important in carbon cycle and soil carbon sequestration. Some methods, which have been widely used, include component integration method, root biomass extrapolation method, root exclusion method, and isotopic method and so on, are compared and appraised. Component integration involves separation of the constituent soil components contributing to CO2 efflux (i.e., roots, sieved soil, and litter) followed by measurements of the specific rates of CO2 efflux from each component part. Rates of all component parts are then multiplied by their respective masses and summed to yield an integrated total of TScer. Root biomass extrapolation based on the variety of root biomass and soil respiration flux at different sites, thus we can estimate the root contributions to total soil respiration. Existing root exclusion techniques may be categorized into three broadly defined areas: root removal, roots are removed, soil is placed back in reverses order of removal, and further root growth is prevented by barriers (alternatively, roots may be removed after a series of TScer measurements ); trenching, existing roots are severed by trenching at a plot boundary but not removed, and a barrier is installed to inhibit future root growth; and gap analysis, aboveground vegetation is removed from relatively large areas (e.g., clearcutting in forests) and TScer measurements in the gap are compared to TScer data for a forested area. Isotopic methods can be broadly classified as pulse labelling and continuous labeling. Isotopic methods have an advantage over other methods because they allow partitioning of TScer between root respiration and soil organic matter decomposition in situ, and avoid the disturbance effects. The comparison and application of these methods have been discussed.
出处
《地球科学进展》
CAS
CSCD
2003年第4期597-602,共6页
Advances in Earth Science
基金
国家重点基础研究发展规划项目"青藏高原农田和草原生态系统温室气体排放及其对全球变化的响应"(编号:G1998040800)资助
关键词
土壤呼吸
根系呼吸
区分方法
Soil respiration
Root respiration
Differential methods
