中文摘要：

通过对西南地区典型喀斯特干热河谷地带乔木林、灌木林及草丛下所覆盖的土面、石面、石沟、石洞、石缝、石槽和石坑7类小生境土壤样品碳氮含量分布特征进行研究,结果表明：研究区域内小生境表层土壤中有机碳和全氮的含量分别介于10.6-103.7 g/kg和1.16-6.39 g/kg之间,变幅较大;不同植被类型下小生境土壤碳氮的含量分布存在明显差异,乔木林下小生境土壤碳氮平均含量较草丛增加100%以上,灌木林下小生境土壤碳氮的空间变异性最小,小生境土壤碱解氮在各植被类型下服从正态分布,有机碳及全氮则服从右偏态分布;小生境相对开放的土面、石面、石坑及石沟普遍较石槽、石缝及石洞土壤有机碳和全氮的含量高,而碱解氮的变化规律不明显。在同种植被类型下,土壤有机碳与全氮、碱解氮、速效磷和碳氮比均表现出良好的相关性。

英文摘要：

The distribution of the contents of soil carbon and nitrogen were explored in seven kinds of micro-habitats（earth flatland,rocky flatland,stone crevice,stone gully,stone cavern,stone groove and stone pit） under different vegetation types（shrub,forest and grassland） in karst region of south western China.The results showed that organic carbon and total nitrogen contents in top soils varied from 10.6 to 103.7 g/kg and from 1.16 to 6.39 g/kg respectively in study area.Distribution of the contents of soil carbon and nitrogen were obvious different under different vegetation types.As to forest,the average contents of soil carbon and nitrogen were doubled 100% more when compared with grassland;as to shrub,the spatial variability of the contents of soil carbon and nitrogen were small.The contents of soil organic carbon and nitrogen were normally distributed under different vegetation types,while the contents of organic carbon and total nitrogen showed right-skewed distribution.The contents of soil organic carbon and total nitrogen were higher in relatively open habitats（earth flatland,rocky flatland,stone crevice and stone pit） than the others.The correlations between the contents of soil organic carbon,total nitrogen,alkaline hydrolytic nitrogen,Olsen-P and carbon nitrogen ratio were significantly correlated in same vegetation type.