Abstract:

Through comparing the concentration and inventory of soil organic carbon (SOC) and its distribution in the soil profiles under several reafforestation patterns, this paper studied the effect of different reafforestation patterns on SOC in the 0～60 cm soil layer located in Lanlingxi drainage area of Zigui county, the three gorges reservoir area. The results showed: In five years after the beginning of the project of Grain for Green, the concentration and inventory of SOC in the 0～30 cm soil layer under most reafforestation patterns were higher than those under contrast 2 (cropland) conditions, while the concentration and inventory of SOC in the 0～60 cm soil layer did not change or even decreased in some cases. The concentration and inventory of SOC and the decreasing magnitude of SOC with the soil profile depth under all the studied reafforestation patterns were lower than those under contrast 1 (shrubbery land) conditions, which received the least impact of land use change. It is thus suggested that the impact of the five-years reafforestation patterns on the SOC in the 0～60 cm soil layer is insignificant. In contrast, the impact of the land use change could be one of the controlling factors affecting SOC in the three gorges reservoir area.

Key words: soil organic carbon, reafforestation patterns, the three gorges reservoir area