| 土地利用及退耕对喀斯特山区土壤活性有机碳的影响 |
| 摘要点击 2616 全文点击 1225 投稿时间：2013-04-12 修订日期：2013-05-07 |
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| 中文关键词 喀斯特山区 土地利用 退耕 活性有机碳 组内-组间主成分分析 |
| 英文关键词 Karst mountain area land use land abandonment labile organic carbon(LOC) within-between PCA |
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| 中文摘要 |
| 以西南喀斯特山区几种典型土地利用方式为对象，研究了土地利用及退耕对全土、团聚体活性有机碳及其恢复能力的影响. 结果表明，随土壤深度的增加，土壤活性有机碳含量及其离散程度呈下降趋势，其中0~10 cm 土壤活性有机碳含量与10~20 cm和20~30 cm 两个剖面层次达极显著（P<0.01）差异水平；活性有机碳含量在0~10 cm 范围内以<0.25 mm 团聚体粒径最高，然而在10~20 cm和 20~30 cm活性有机碳在各粒径中的分布并不明显；不同土地利用方式下，水田中无论全土还是团聚体中活性有机碳均表现出较高水平，灌从次之，而以退耕3 a草丛最低. 组内-组间主成分分析表明，土地利用方式与土壤活性有机碳的累积特征表现为水田>灌丛>退耕15 a草丛≈旱地>退耕3 a草丛，其中退耕15 a草丛在0~10 cm深度下较旱地增加了20.3%，且达到灌丛土壤活性有机碳的80%，表明喀斯特山区土地退耕初期土壤有机碳恢复速度相对缓慢，而随退耕时间的推移，土壤碳汇效应逐步显现. |
| 英文摘要 |
| Effects of land use and land abandonment on labile organic carbon (LOC) in whole soils and different aggregate sizes were studied by sampling analysis of the soils in some typical land uses of the Karst region, southwest China. Results showed that the content and degree of dispersion of labile organic carbon decreased with soil depth, and the content of LOC was highly significant (P<0.01) in 0-10 cm than in 10-20 cm and 20-30 cm. In the 0-10 cm soil layer, the content of LOC distribution in different aggregates was higher in the<0.25 mm size, while no obvious changes of LOC among aggregates were found in the 10-20 cm and 20-30 cm depths. In different land use patterns, the LOC was the highest in paddy whether in whole soils or aggregates, followed by shrub, and the lowest in abandoned 3 years grassland. Within-between principal component analysis showed that the accumulation characters between land use and LOC were in the order of paddy>shrub>abandoned 15 years grassland≈dry land>abandoned 3 years grassland, the content of LOC increased by 20.3% as compared to dryland, and had reached 80% of the content of shrub in abandoned 15 years grassland at the 0-10 cm depth, indicating that at the early stage of land abandonment, the natural recovery of carbon is relatively slow, while with the abandonment time increase, the carbon sink effect gradually appear. |
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