作　　者： ; ; ; ;

机构地区： 中山大学地理科学与规划学院

出　　处： 《地球科学进展》 2004年第5期793-801,共9页

摘　　要： 土壤是陆地生态系统中最大的碳库。土壤碳动力学旨在研究土壤有机碳库的大小及更新速率。土壤有机碳库可分为3个亚碳库:"活动"、"缓慢"和"稳定"碳库。碳同位素特别是14C可作为研究土壤碳动力学的理想示踪剂;δ13C值是定量研究C3和C4植被更替历史的有效手段;14C示踪及年代测定与13C信号联合使用,可以估算土壤碳库的大小和驻留时间。碳同位素示踪应用于土壤碳动力学研究取得了较大进展,但是由于缺乏可靠的全球数据库和标准方法来量化土壤有机碳库,导致对土壤各亚碳库的大小和更新速率以及土壤CO2的估算仍存在较大的不确定性,从而难以估计土壤碳库大小的变化对大气CO2浓度和全球气候变化的潜在贡献。 Soils are the largest carbon reservoir in terrestrial ecosystems. Soil organic matter contains generally three identifiable carbon pools: 'active' pool; 'slow' pool and 'passive' pool. The dynamics of the soil carbon cycle focus on mostly carbon turnover times and input rates and size of soil carbon pools on various time scales. Many researchers indicated that natural abundance of carbon isotopes, in particular radiocarbon,is useful tracers in the study of the soil carbon cycle. δ~ (13)C values of soil organic matter provide a unique tool for quantifying historical shifts between C3 and C4 ecosystems over decadal to millennial time scales.~ (14)C signature, the combination of~ (14)C dating and~ (13)C signature can be used to determine the size and turnover rates of the labile and stable soil organic matter pools. Despite the advances in the study of the soil carbon cycle by means of carbon isotopes signature in recent decades, the isotopic approaches to the study of the soil carbon cycle have limitations. Tremendous uncertainties exist in the estimation of sizes and turnover times of soil carbon pools as well as the amount of~ (14)C content of SOM derived CO(2) because of a lack of reliable global database and a lack of standard methods available to quantify labile and stable soil organic matter pools. It is very difficult to estimate any change in the size of the soil C pool that could potentially alter the atmospheric CO(2) concentration and the global climate.

关 键 词： 土壤碳动力学 碳同位素 土壤有机质 更新速率 全球变化

领　　域： [农业科学] [农业科学]