不同林地恢复模式下露天煤矿排土场土壤有机碳分布特征

研究露天煤矿排土场6种不同林地植被恢复模式和撂荒地0～100 cm土层土壤有机碳(SOC)含量和储量的分布特征，分析其差异性及其影响因素.结果表明：不同林地0～10 cm土层SOC含量比撂荒地(1.92 g·kg^-1)显著提高23.8%～53.2%，10～20 cm土层比撂荒地(1.39 g·kg^-1)显著提高5.8%～70.4%，20 cm土层以下与撂荒地相比差异不大；各土层SOC含量随土层深度增加而逐渐减小，表层(0～20 cm)减小幅度大于深层(20～100 cm).不同林地SOC储量在表层明显高于深层，随土层深度增加而逐渐减小.0～100 cm土层林地SOC储量比撂荒地(17.52 t·hm^-2)提高18.1%～42.4%，其中，紫穗槐林地SOC储量最高，达24.95 t·hm^-2，明显高于其他林地类型，灌木林地SOC储量比乔木高12.4%.林地凋落物、细根生物量和土壤水分都与排土场SOC呈显著正相关.综上所述，不同人工林地恢复模式显著提高了排土场0～100 cm土层SOC，尤其对表层SOC提高效果明显，但排土场SOC与原地貌相比差距仍较大.从提高排土场SOC角度优先推荐紫穗槐为主要林地植被.

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 higher 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.