摘要
在贵州喀斯特区域一块典型的退耕弃荒洼地中央和周边坡面采集了4个土壤剖面,研究土壤有机碳（SOC）含量和δ^13Corg值的变化.结果表明,坡面不同土壤层次SOC的变化范围为6.0-92.3 mg·kg^-1,并沿着土壤层次的加深迅速降低,变化幅度远远大于洼地土壤剖面（6.3-26.7 mg·kg^-1）.坡面土壤δ^13Corg介于-25.103‰和-23.666‰之间,但各剖面土层内部δ^13Corg变化趋势不一致.洼地土壤δ^13Corg介于-23.495‰和-20.809‰之间,并随着土壤层次的加深δ^13Corg逐渐增加.洼地土壤剖面层次内C4-C占SOC的比例随土壤层次的加深逐渐增加,与林-农生态系统转变过程中的变化趋势相反;土壤δ^13Corg与C3-C之间呈显著相关性（R^2=0.7806,n=7）,对δ^13Corg起到主要影响作用的是退耕弃荒后新加入的C3-C.
Four soil profile samples were collected in the middle of de-farming and wasteland billabong and around slopes,located at typical karst district of Guizhou province.Soil organic matter（SOC） content and δ^13Corg were determined. SOC content ranged from 6.0mg·kg^-1 to 92.3mg·kg^-1,and decreased with depth at slope soil profiles.The range of value was bigger than that at billabong soil profile（6.3～26.7mg·kg^-1）.The value of δ^13Corg at slope profiles was between-25.103‰ and-23.666‰,but variation direction of three slope soil profiles was different.The value of δ^13Corg in billabong soil profile was between-23.495‰ and-20.809‰,and increased with depth.The percentage of C4-C increased with depth in billabong soil profile.The correlation between δ^13Csoc） and C4-C,C3-C was significant（R=0.884,n=7）,influenced by new C3-C.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2007年第9期1912-1917,共6页
Environmental Science
基金
国家重点基础研究发展规划(973)项目(2006CB403200)
关键词
退耕弃荒
洼地
有机碳
来源
δ13C
de-farming and wasteland
billabong
organic carbon
origin
δ^13C
