中文摘要：

研究了贵州西南部典型喀斯特山区不同植被类型下常规土壤及小生境土壤中有机碳及不同粒径土壤颗粒有机碳的变化.结果表明：不同植被类型下,常规及小生境土壤有机碳含量均表现为：裸地〈草丛〈灌木林〈乔木林,常规土壤变幅在7.18～43.42g·kg-1,土面和石坑土壤有机碳变幅分别为6.62～46.47g·kg-1和9.01～52.07g·kg-1;颗粒有机碳（POC）/矿物结合态有机碳（MOC）值均为：裸地〈草丛〈乔木林〈灌木林,同一植被类型下,与常规及土面相比,石坑中土壤POC/MOC值最高;植被在由裸地-草丛-灌木林-乔木林的变化过程中,不同粒径土壤颗粒有机碳含量增加,而土壤有机碳主要以砂粒及粉砂粒有机碳形式存在,说明喀斯特地区土壤的固碳能力及有机碳稳定性较弱,土壤易受外界干扰而引发有机碳流失,土壤质量存在下降或退化的风险.

英文摘要：

This paper studied the variation characteristics of soil organic carbon （SOC） and different particle sizes soil particulate organic carbon （POC） in normal soil and in micro-habitats under different vegetation types in typical Karst mountain areas of southwest Guizhou. Under different vegetation types, the SOC content in normal soil and in micro-habitats was all in the order of bare land grass shrub forest, with the variation range being 7.18-43.42 g·kg-1 in normal soil and being 6.62-46.47 g·kg-1 and 9.01-52.07 g·kg-1 in earth surface and stone pit, respectively. The POC/MOC （mineral-associated organic carbon） ratio under different vegetation types was in the order of bare land grass forest shrub. Under the same vegetation types, the POC/MOC in stone pit was the highest, as compared to that in normal soil and in earth surface. In the process of bare land-grass-shrub-forest, the contents of different particle sizes soil POC increased, while the SOC mainly existed in the forms of sand- and silt organic carbon, indicating that in Karst region, soil carbon sequestration and SOC stability were weak, soil was easily subjected to outside interference and led to organic carbon running off, and thus, soil quality had the risk of decline or degradation.