By taking the 3 major successional communities (arbor forest, secondary forest and shrubbery) of karst primary forests in Maolan Nature Reserve in Guizhou province as the research subjects, the organic carbon contents of soil, density and vertical distribution characteristics were investigated. The results show as follows: 1) The organic carbon in different succession communities of karst primary forest, secondary forest and shrubbery were respectively 81.9508 g/kg, 52.1712 g/kg, 38.3804 g/kg and the carbon density was respectively 11.6311 kg/m2, 10.7447 kg/m2 and 7.4118 kg/m2; 2) Both the organic carbon contents and carbon density of the soil decreased gradually with the deepening of the soil in all the 3 major successional communities and the organic carbon contents were respectively 107.2594 g/kg, 63.2031 g/kg and 51.2267 g/kg in the 0-10 cm-deep soil, as 1.21-1.33 times high as the average values of the whole soil profile; the carbon density were the highest in the 0-10 cm-deep soil for all the 3 major successional communities, accounting for 55.11%, 54.44% and 63.50% of the whole soil profile, and such characteristics indicate the soil carbon was more or less concentrating on the surface of the soil; 3) For all the 3 major successional communities, there were strong positive correlations between the soil carbon contents and total N, available potassium as well as maximal water holding capacity, and strong negative correlations between the soil carbon contents and soil density. There were high accuracy concerning the established regression equations, and the different dominant factor in the soil had impact on the carbon contents of all the 3 different successional communities.%摘要森林土壤有机碳是土壤有机碳库的重要组成部分,研究森林土壤有机碳对于应对气候变化具有非常重要.以茂兰自然保护区喀斯特植被3种演替换群落喀斯特乔木林、次生林和灌木林为研究对象,分析了不同演替群落的土壤有机碳含量和密度及其在土壤剖面上分布的差异,以及有机碳含量和土壤理化性状的相关性.结果表明:①3种不同演替群落在整个剖面上(0～20 cn)土壤有机碳含量和碳密度的表现均为喀斯特乔木林(81.950 8 g/kg、11.631 1 kg/m2)＞次生林(52.171 2 g/kg、10.744 7 kg/m2)＞灌木林(38.380 4 g/kg、7.411 8 kg/m2)；②3种不同演替群落有机碳含量和碳密度均随着土壤深度的增加而降低；0～10cm有机碳含量为喀斯特乔木林107.259 4g/kg、次生林63.203 1 g/kg和灌木林51.226 7 g/kg,分别是其整个土壤剖面有机碳含量均值的1.31、1.21和1.33倍；土壤有机碳密度均以0～10 cm为最大,分别占整个土壤音面有机碳密度的55.11％、54.44％和63.50％,介于6.41～4.71 kg/m2之间,具有一定程度的表聚性；③3种不同演替群落的土壤有机碳含量与土壤全N、速效K和最大持水量均表现为显著或极显著正相关,与土壤密度表现为极显著负相关；不同演替群落影响其土壤有机碳含量的主导因子不同；各演替群落的土壤有机碳含量与土壤理化性状的回归方程具有很高的相关性,可以正确反映两者之间的关系.
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