Based on the field surveys and laboratory analysis,the contents of surface soils (0 ～20 cm) organic C (SOC) and total N (TN) in dry land,bare land,grassland and woodland were investigated in the Chenjiazhai watershed of typical Karstic plateau of middle Guizhou.The results showed that the mean contents of SOC and TN was 36.71 g · kg-1 and 1.61 g · kg-1,respectively.The contents of SOC and TN in the dryland were 26.78 g · kg-1 and 1.37 g · kg-1,respectively.The slope upland had lower content of SOC and TN than terrace dry land,conversely,the depression dry land had higher content of SOC and TN in comparison with the terrace dry land.Compared with the dry land,the contents of SOC and TN in bare land was obviously lower,being 7.82 g · kg-1and 0.78 g · kg-1,respectively,while those in grassland were higher.The average contents of SOC and TN in woodland were 98.2％ and 42.0％ higher than those in dry land.The variation coefficients of SOC and TN in the area were 48.18％ and 35.16％,respectively.The highest values (44.96％ and 43.43％,respectively) were observed in dry land,followed by that in woodland,and the lowest ones were investigated in grassland and bare land (less than 5％).Soil C/N ratio was increased in the order of bare land,dry land,grassland and woodland.Under these four land use types,there was a significant positive correlation between SOC and TN (r =0.9131).The bare land and slope land could not significantly promote the accumulation of surface SOC and TN in Karstic area,while the conversion of slope land into woodland or grassland was conducive to the accumulation of SOC and TN distinctly.%通过野外调查和室内分析,对贵州中部典型喀斯特高原地貌类型的陈家寨小流域裸地、旱地、草地和林地4种土地利用类型表层(0 ～20 cma)土壤有机碳(SOC)和全氮(TN)含量特征进行了研究.结果表明:该区SOC含量平均值为36.71 g/kg,TN平均值为1.61 g/kg.其中,旱地SOC和TN平均值分别为26.78 g/kg和1.37 g/kg,且坡耕地较低,洼旱地较高.与旱地相比,裸地SOC平均值(7.82 g/kg)和TN(O.78 g/ks)平均值远低于旱地,草地较高.林地SOC和TN平均值较旱地高98.2％和42.0％.该区SOC和TN含量的变异系数为48.18％和35.16％,以旱地最大(44.96％和43.43％),林地次之,草地和裸地较小(低于5％).土壤C/N比依裸地、旱地、草地和林她的顺序递增.该区各类土地利用方式下的SOC和TN呈极显著正相关(r=0.9131).喀斯特小流域裸地和坡旱地对表层SOC和TN的积累效果不明显；通过退耕还林还草能够有效地增加表层SOC和TN的积累.
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