南方侵蚀治理区土壤碳分布及主控因素研究

研究侵蚀治理区土壤碳区域分布影响因素对揭示退化土壤有机碳恢复有重要的意义。本文以江西省兴国县侵蚀治理恢复区林地土壤有机碳为研究对象，评价了土壤类型和成土母质对土壤有机碳的影响及其主控作用。结果表明：兴国县侵蚀治理恢复区林地土壤有机碳受土壤类型和成土母质影响显著，其中黄红壤各土层土壤有机碳含量均显著高于红壤；千枚岩发育的土壤有机碳显著高于红砂岩和花岗岩。对比土壤类型和成土母质对土壤有机碳的影响作用大小发现，在表层0 ~ 20 cm土壤类型对土壤有机碳变异解释能力大于30%，成土母质的解释能力约为17%，土壤类型是影响表层土壤有机碳的主控因素；表下层20 ~ 30 cm 土壤有机碳变异的解释能力则表现为成土母质(28.8%)与土壤类型(27.5%)基本相当，同为主控因素。因此，兴国县侵蚀治理恢复区土壤类型和成土母质对土壤有机碳的影响作用不容忽视，合理地分区展开水土保持工作有利于退化土壤的碳恢复。

Regional Distribution of Soil Organic Carbon and Its Controlling Factors in the Severely Eroded Region of South China

Investigating the primary factors of soil organic carbon (SOC) is important to elucidating the recovery mechanisms of soil organic carbon in degraded soils. A case study in Xingguo County of Jiangxi Province was conducted to assess the effects of soil type and parent material on soil organic carbon of forests in the eroded region. The results showed that significant differences were found in SOC content within soil types and parent materials, respectively. In general, yellow-red soils contained a markedly larger SOC content than red soils in all soil layers. SOC content on phyllite was considerably more than that developed on red sandstone and granite. Meanwhile, as for the contribution to the variability of SOC content, soil type explained over 30% of the variability of SOC content while parent material explained approximately 17% in the surface soil layer 0-20 cm, therefore, soil type played a more important role than parent material on SOC in the surface soil layers. However, in the 20-30 cm soil layer, the independent contributions of parent material and soil type to SOC content variability were roughly equal, respectively with 28.8% and 27.5%, which indicated that both parent material and soil type were considered as the main controlling factor in subsurface soil layers. Hence, the effects of soil type and parent material on SOC should not be neglected in the severely eroded region, and different water and soil conservation measures implementation in different regions can be benefit for soil carbon restoration of degraded soils.