人为土壤有机碳的分布特征及其固定意义  

CHARACTERISTICS OF ORGANIC CARBON DISTRIBUTION IN ANTHROPOGENIC SOILS AND ITS IMPLICATION ON CARBON SEQUESTRATION

作　　者：张甘霖[1] 何跃[1] 龚子同[1] 

机构地区：[1]中国科学院南京土壤研究所土壤与农业可持续发展国家重点实验室,南京210008

出　　处：《第四纪研究》2004年第2期149-159,共11页Quaternary Sciences

基　　金：国家自然科学基金重点项目 (批准号:40 2 3 5 0 5 4);中国科学院知识创新工程重要方向项目(批准号 :KZCX3 -SW -4 2 7);中国科学院知识创新工程领域前沿项目(批准号 :ISSASIP0 10 6)资助

摘　　要：文章在分析不同类型的人为土壤形成过程及其特点的基础上研究了人为土壤有机碳含量、分布年龄与同位素组成特征。结果表明 ,人为土壤中有机碳的含量分布不同于起源土壤或者相应的非人为土壤 ,主要体现在有机碳含量降低的缓慢和不规则性以及有机碳含量的相对富集。通过计算证明人为土壤的有机碳密度高于相邻土壤或起源土壤。放射性碳测定表明人为土壤中的有机碳年龄较老 ,说明了有机碳在这些土壤中存在的相对稳定性。土壤有机碳的稳定同位素组成分析表明 ,土壤中深层的有机碳与现代有机碳来源不同 ,也表明了土壤中有机碳的稳定存在。文章还分析了人为土壤中有机碳富集和稳定的可能机制 ,包括物理、化学和生物学机制 ,认为就有机碳的固定而言 。Landuse related human activities are important factors that affect soil organic carbon turnover and global carbon cycling. Anthropogenic soils were formed by long term and intensified human activities under various natural backgrounds. This paper summarized the peculiarities of pedogenic processes of the major kinds of anthropogenic soils and analysed their main characteristics that can contribute to the increased storage of organic carbon in soils. We found that anthropogenic soils were generally thicker in effective soil depth and higher in organic carbon content, as compared to their originating or neighboring natural soils. The distribution pattern of organic carbon in profile was different from that of natural soils but showing an irregularly decreasing pattern with soil depth. Anthropogenic soils contained relatively high organic carbon in deep part of the pedons. We calculated the densities of organic carbon (kilogram per square meter) of all major anthropogenic soils and found that they were higher than their originating or neighboring counterparts. The ratio of carbon density in surface to that of one meter deep soil body was lower in anthropogenic soils than that of natural soils, showing the contribution of the increased soil depth to total organic carbon storage in anthropogenic soils. The 14 C ages of an ancient Hydragric Anthrosols and typical Irragric Anthrosols showed that organic carbon in these anthropogenic soils were quite old and this indicated the relatively stable existence of organic carbon in anthropogenic soils. δ 13 C data from a typical Irragric Anthrosols also indicated that the buried soil organic carbon had little exchange with modern organic matter, and proved the stability of organic carbon in these soils. This paper suggested several possible mechanisms that could contribute to the increase and immobilization of organic carbon in anthropogenic soils. They include physical fractionation and stabilization, chemical structure change, especially humus composition

关 键 词：人为土壤 有机碳 碳分布 碳固定 

分 类 号：S151.93[农业科学—土壤学]