喀斯特高原区植被恢复过程土壤有机碳的变化

Changes of Soil Organic Carbon During Vegetation Restoration Process in Karst Plateau

土壤有机碳(SOC)作为评价土壤碳汇的重要指标,SOC动态变化与组分土壤碳的流向特征对进一步理解喀斯特地区植被与全球碳平衡关系具有重要意义。本研究以贵州喀斯特高原为研究区域,采集植被恢复过程中草本群落(Herb community stage,Hcs)、灌木群落(Shrub community stage,Scs)、乔林群落(Arbor community stage,Acs)三个阶段下0~10 cm土层(S1层)、10~20 cm土层(S2层)、20~30 cm(S3层)的土壤混合样本共27份,对SOC含量垂直分布特征、土壤粗颗粒有机碳(CPOC)、土壤细颗粒有机碳(FPOC)、土壤黏粉粒有机碳即矿物结合态有机碳(MOC)含量及比例变化特征、以及POC(颗粒有机碳)/MOC比值变化特征等进行研究,探究在喀斯特高原区植被恢复对SOC的影响。结果表明:(1)随植被恢复SOC含量上升,随土层加深SOC含量降低;(2)不同组分土壤碳含量表现为,CPOC>FPOC>MOC;CPOC、FPOC占比最大,是SOC的主要组分;(3)Acs下POC/MOC比值最小。植被恢复对SOC具有重要影响,是增强喀斯特地区固碳能力的有效途径之一。

Soil organic carbon(SOC)is an important index to evaluate soil carbon sink.The dynamic changes of SOC content and the flow direction characteristics of soil carbon of different components are of great significance to further understand the relationship between vegetation in karst area and global carbon balance.The karst plateau of Guizhou was taken as the research area,where a total of 27 soil mixed samples that from 0~10 cm soil layer(S1 layer),10~20 cm soil layer(S2 layer)and 20~30 cm soil layer(S3 layer)at the stage of herb community(herb),shrub community and forest community(forest)during the vegetation restoration process were collected.These samples are used to study the vertical distribution characteristics of SOC content,the variation characteristics of soil carbon content and proportion of different components(soil coarse-particulate organic carbon(CPOC),soil fine-particulate organic carbon(FPOC),soil clay particle carbon namely mineral bound organic carbon(MOC)),and the variation characteristics of POC(particulate organic carbon)/MOC ratio,so as to explore the impact of vegetation restoration on SOC in Karst Plateau area.The results showed that:(1)SOC content increased with vegetation restoration and decreased with soil deepening;(2)The content of soil carbon in different components was CPOC>FPOC>MOC;CPOC and FPOC account for the largest proportion and were the main components of SOC;(3)The POC/MOC ratio was the smallest in the forest stage.Vegetation restoration has an important impact on soil organic carbon and is one of the effective ways to enhance the carbon sequestration capacity in karst areas.