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以贵州西南部典型喀斯特干热河谷地区荒草地(Ⅰ)、小灌丛(Ⅱ)、灌木疏林(Ⅲ)、灌木林(Ⅳ)和乔木林(Ⅴ)下一般土壤、石缝土壤和石沟土壤为研究对象,对比研究其土壤微生物生物量碳(MBC)、可溶性有机碳(DOC)、易氧化有机碳(EOC)和基础呼吸量(BR)的变化。结果表明:土壤MBC、DOC含量分别为123.2~616.8 mg kg-1和76.6~258.6 mg kg-1,EOC、BR含量分别为1.62~8.32 g kg-1和15.9~41.6 CO2μl g-1h-1。不同植被类型下,一般土壤、石缝土壤和石沟土壤MBC、DOC、EOC和BR含量均表现为:Ⅴ>Ⅳ>Ⅲ>Ⅱ>Ⅰ,差异显著,且土壤EOC与土壤总有机碳的比值总体也呈增加趋势。同一植被类型中,与一般土壤和石缝土壤相比,石沟土壤中EOC和DOC表现出了较高的含量水平。相关性分析表明,MBC、DOC和EOC可以作为喀斯特干热河谷地区土壤有机碳变化的敏感性指标。
In the typical karst dry-hot valley in the southwestern Guizhou Province, soil samples of common soils, stone soil and stoner (Ⅰ), scrub (Ⅱ), shrubbery (Ⅲ), shrub (Ⅳ) and arbor (Ⅴ) Ditch soil was selected to study the changes of soil microbial biomass carbon (MBC), dissolved organic carbon (DOC), organic carbon (EOC) and basal respiration (BR). The results showed that the contents of MBC and DOC in soil were 123.2-616.8 mg kg-1 and 76.6-258.6 mg kg-1, respectively. The contents of EOC and BR were 1.62- 8.32 g kg-1 and 15.9-41.6 CO2μl g-1h-1, respectively. Under different types of vegetation, MBC, DOC, EOC and BR contents of soils, rock seams and rock ditches were significantly different: Ⅴ> Ⅳ> Ⅲ> Ⅱ> Ⅰ, and the ratio of soil EOC to total soil organic carbon The overall trend is also increasing. In the same vegetation type, EOC and DOC showed a higher content in the soil of the gully than in the soil of the general soil and the rock. Correlation analysis showed that MBC, DOC and EOC could be used as sensitive indicators of soil organic carbon change in karst dry-hot valley.