| 退耕弃荒洼地土壤有机碳在生态系统转化过程中的动态变化 |
| 摘要点击 2099 全文点击 1428 投稿时间：2006-11-06 修订日期：2007-02-07 |
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| 中文关键词 退耕弃荒 洼地 有机碳 来源 δ13C |
| 英文关键词 de-farming and wasteland billabong organic carbon origin δ13C |
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| 中文摘要 |
| 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δ13Corg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δ13Corg 介于-25.103‰和-23.666‰之间,但各剖面土层内部δ13Corg变化趋势不一致.洼地土壤δ13Corg 介于-23.495‰和- 20.809‰之间,并随着土壤层次的加深δ13Corg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δ13Corg与C3-C之间呈显著相关性（R2=0.7806，n=7），对δ13Corg起到主要影响作用的是退耕弃荒后新加入的C3-C. |
| 英文摘要 |
| 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 δ13Corg were determined. SOC content ranged from 6.0 mg·kg-1 to 92.3 mg·kg-1, and decreased with depth at slope soil profiles. The range of value was bigger than that at billabong soil profile（6.3～26.7 mg·kg-1）. The value ofδ13Corg at slope profiles was between -25.103‰ and -23.666‰,but variation direction of three slope soil profiles was different. The value ofδ13Corg 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 δ13Csoc and C4-C，C3-C was significant（R=0.884，n=7）, influenced by new C3-C. |
