Abstract: The influence of land cover change on soil organic carbon (SOC) inventory from shifting sandy to other land cover types was investigated by comparing the concentration and its distribution in soil profile under the artificial forest (Populus alba var. pyramidalis, Pinus sylvestris var. mongolica, Caragana microphylla), fenced land, moderate grazing land, cropland (maize) and fixed sandy land, which have been established on shifting sandy land for about 25 years. The increase of SOC content in 0-60 cm soil profile among all the cover types was found under cropland, which was 3.97 times that of shifting land, additionally, significant differences were observed at each soil layer between cropland and shifting land. SOC content within the whole profile is 80%, 138% and 73% higher under three types vegetation of artificial forest than that of shifting sandy land, respectively. The difference of SOC content between artificial forest and shifting sandy land was greater in 0-20 cm than in 20-60 cm soil layer, while that between fenced land and shifting sandy land was greater in 0-40 cm than in 40-60 cm soil layer. Variation of soil organic carbon density (SOCD) was similar to that of soil organic carbon content. The main differences are concentrated in 0-20 cm soil layer which is mostly caused by the soil bulk density. Average cluster analysis on SOCD indicated that eight land cover types could be divided into four groups:CL1 (cropland), CL2 (P. alba var. pyramidalis, fenced land, moderate grazing land), CL3 (P. sylvestris var. mongolica, C. microphylla, fixed sandy land) and CL4 (shifting sandy land). In conclusion, the distribution of SOC concentration or inventory in soil profile would change with the alternation of land cover in the southern Horqin Sandy Land.

Key words: land cover, soil organic carbon, carbon concentration, Horqin Sandy Land