中文摘要：

利用第二次全国土壤普查资料,以安徽六安市域为例研究统计了土壤表土有机碳平均含量随土壤分类级别的变异,结果表明供试市域的土壤有机碳含量在不同分类单元层次上上存在明显差异。表土有机碳含量的变化范围介于4.58 g kg^-1～60.38 g kg^-1,在土种尺度上变异系数为4.29%～83.78%,土属尺度上变异系数为0.88%～120.56%;亚类尺度上为11.97%～95.37%,而土类尺度上为18.92%～95.42%。

英文摘要：

Base on the data of the second national soil survey of Luan in 1986,the different variation analysis of spatial distribution and soil taxonomy unit of topsoil organic carbon in Luan was studied.The results showed that the topsoil organic carbon in Luan had a significant change at different soil taxonomy unit levels.The change was much greater at soil group than that at soil species level.In the different types of land use,every soil taxonomy unit（from soil species to great soil group） all showed that soil organic carbon content was the highest（up to 13.99±2.19 g kg^-1） in non-cultivation soils,and the lowest was in dry cropland（8.44±0.92 g kg^-1）,and paddy soil organic carbon content was 10.36±1.58 g kg^-1.The variable coefficient was the lowest in paddy soils（17.19%）,and the highest was in non-cultivation soils（40.01%）,whereas variable range was not significant.All results showed content of soil organic carbon variability depended on spatial scale and natural condition.