[Distribution characteristics of soil organic carbon under different forest restoration modes on opencast coal mine dump].

The content and storage of soil organic carbon (SOC) were compared in six wood restoration modes and adjacent abandoned land on opencast coal mine dump, and the mechanisms behind the differences and their influencing factors were analyzed. Results showed that the contents of SOC in six wood lands were significantly higher (23.8%-53.2%) than that of abandoned land (1.92 g · kg⁻¹) at 0-10 cm soil depth, the index were significantly higher (5.8%-70.4%) at 10-20 cm soil depth than the abandoned land (1.39 g · kg⁻¹), and then the difference of the contents of SOC in the deep soil (20-100 cm) were not significant. The contents of SOC decreased with increase of soil depth, but the decreasing magnitude of the topsoil (0-20 cm) was higher than that of the deep soil (20-100 cm). Compared with the deep soil, the topsoil significant higer storage of SOC in different woods, the SOC storage decreased with the soil depth. Along the 0-100 cm soil layer, the storage of SOC in six wood lands higher (18.1%-42.4%) than that of the abandoned land (17.52 t · hm⁻²). The SOC storage of Amorpha fruticosa land (24.95 t · hm⁻²) was obviously higher than that in the other wood lands. The SOC storage in the shrub lands was 12.4% higher than that of the arbor woods. There were significantly positive correlations among forest litter, fine root biomass, soil water content and SOC on the dump. Consequently, different plantation restorations significantly improved the SOC level on the dump in 0-100 cm soil, especially the topsoil. But there was still a big gap about SOC level between the wood restoration lands and the original landform. To improve the SOC on opencast coal mine dump, A. fruticosa could be selected as the main wood vegetation.