为研究云南省植烟土壤有机碳分布特征及区域差异，在云南省烟草种植区域内，选择代表性植烟土壤进行剖面各层次土壤样品采集，对土壤有机碳密度含量范围、垂直分布特征及与土壤理化性状之间的关系进行研究。结果表明：（1）云南植烟土壤有机碳平均密度达10.21 kg/m2，植烟土壤类型中红壤有机碳密度较高，紫色土和黄壤有机碳密度较低。（2）植烟土壤有机碳密度随土层的加深而减少，黄壤各层次有机碳密度的差异较大，变异系数为122.35%；红壤各层次有机碳密度差异较小，变异系数在17.67%~ 49.60%，红壤有机碳密度较为稳定。（3）植烟土壤有机碳密度与土壤持水量呈显著正相关关系，与土壤总孔隙度相关关系不显著，与粘粒含量呈极显著正相关。植烟土壤有机碳氮质量比(C/N)在1.58~14.00，有机碳磷质量比(C/P)在1.26~34.08，红壤的C/N和C/P比值较大。

Study on regional characteristics of soil organic carbon (SOC) in the main region of cultured tobacco in Yunnan, the tobacco-growing soil profiles were collected. According to the content of soil organic carbon density, vertical distribution characters, and the relationships between the soils organic carbon and the soil physical and chemical properties were analyzed. The results showed that: (1) the content of tobacco-growing soil organic carbon density was 10.21 kg/m2. There were high content of soil organic carbon density in red soil, and low content of soil organic carbon density in purple soil and yellow soil. (2)The content of soil organic carbon density showed a reduction in a deeper soil stratum. There was great difference in yellow soil organic carbon density with variation coefficient of 122.35%. Red soil showed that the carbon density was stable and the coefficient of variation was 17.67%-49.60%. (3)The tobacco-growing soil organic carbon density showed a positive correlation with soil water retention and soil clay content, showing no significant correlation with soil porosity. The ratio of organic carbon to nitrogen (C/N) ranged from 1.58 to 14.00. The ratio of organic carbon to phosphorus (C/P) ranged from 1.26 to 34.08. Red soil had the highest ratio of C/N and C/P.