植被恢复对昆阳磷矿土壤有机碳储量的影响

植被恢复是既能保持磷矿开采同时又能有效扼制矿区生态环境的退化，并逐步恢复已退化的矿区生态系统最有效的生物措施。为揭示植被恢复对昆阳磷矿土壤有机碳和碳素积累的影响，研究探讨了昆阳磷矿不同恢复林地的土壤有机碳储量变化。结果表明:（1）不同恢复林地的土壤有机碳含量存在显著差异（p < 0.05），7种不同植被恢复人工林土壤平均有机碳含量分别是废弃地的14.29倍、11.83倍、11.40倍、5.89倍、15.48倍、15.59倍、18.53倍。（2）土壤有机碳在剖面的含量表现出明显的“表聚作用”，均以表土层（0—20 cm）最大，且随土层厚度的增加，呈下降趋势。（3）不同恢复林地的土壤有机碳密度差别较大，变化趋势和土壤有机碳含量的变化趋势一致，且在同一林分土壤中，单位深度土壤各土层平均有机碳密度均以表层最大，随土层的增加而降低。（4）土壤有机碳主要存储于0—20 cm土层中，平均含量为53.60%，随着土层的加深，土壤有机碳所占比重急剧下降，经过植被恢复，7种人工林土壤有机碳储量较废弃地0—20 cm土壤有机碳储量提高了26.53%，20.39%，34.48%，10.81%，28.62%，39.52%，36.71%，说明目前矿区通过植被恢复后的土壤状况显著优于未进行恢复措施的废弃地。

Impacts of Vegetation Restoration on the Soil Organic Carbon Storage in Kunyang Phosphorite Mine

Vegetation restoration can keep phosphate rock mining,effectively curb the mining area ecological environment degradation,and gradually restore the mining area of degraded ecosystem,is one of the most effective measures.The results show that significant differences of soil organic carbon(SOC) contents exist between the different forest types and soil layers,the average organic carbon contents under seven different vegetation restoration plantations (Ⅰ-Ⅶ) are 14.29 times,11.83 times,11.40 times,5.89 times,15.48 times,15.59 times,18.53 times of that of the abandoned land,and the difference is significant (p＜0.05);SOC contents of 7 stands present the phenomenon of surface enrichment,showing a decreasing trend from the surface to the deep layer,SOC content is mainly accumulates in 0-20 cm soil layer;vertical distribution of soil organic carbon densitie and vertical distribution of soil organic carbon content characteristics in seven kinds of stands are consistent,soil organic carbon density reduced with increase of soil depth,with soil organic carbon density in topsoil 0-20 cm is maximum;organic carbon reserves decreased with increase of soil depth,while soil organic carbon was mainly concentrated in the 0-20 cm soil layer,the average content is 53.60％.After vegetation restoration,soil organic carbon contents of 0-20 cm soil layers in 7 kinds of plantations increase by 26.53％,20.39％,34.48％,20.39％,28.62％,39.52％ and 28.62 ％,respectively,indicating that the soil conditions after vegetation restoration are significantly better than that of the remnant waste land without the recovery measures in the current mining area.