不同生长时期丝栗栲林下土壤有机碳含量及矿化特征

[目的]分析土壤活性碳含量变化以及土壤有机碳的矿化特征,为今后深入了解掌握丝栗栲林下土壤有机碳的分解转化过程及其固碳潜力提供理论依据。[方法]基于野外取样调查以及室内分析得出的有机碳数据,利用双指数模型法,在Origin 8.6软件支持下拟合出活性碳含量以及有机碳矿化过程及强度的时空变化特征。[结果]土壤有机碳含量和活性碳含量均呈现明显的表层富集现象以及4月较低,8月最高,之后逐月降低的时间变化特点。土壤有机碳矿化强度虽然表现出与土壤有机碳和活性碳含量相同的垂直剖面特征和时间变化趋势,但其时间变化特征与土壤活性碳含量变化更为一致,只有0—20cm表层土壤表现出显著性变化。[结论]土壤有机碳矿化强度与微生物、温度和活性碳含量均达到极显著相关水平,但其时间变化特征与土壤活性碳含量变化更为一致,二者的关系更密切。

Content and Mineralization Characteristics of Soil Organic Carbon Under Castanopsis Fargesii Forests in Different Growth Periods

[Objective] To analyze mineralization features and content of soil organic carbon in order to provide theoretical basis for future research on decomposition process and carbon sequestration capacity of soil under Castanopsis fargesii forests.[Methods] We obtained soil organic carbon data based on field investigation and laboratory analysis. The Origin 8.6 software was employed in the study. A double exponential model was used to investigate the spatial and temporal variation in activated carbon content and organic carbon mineralization intensity.[Results] Both of the soil organic carbon and activated carbon showed obvious surface enrichment, and this surface enrichment increased from the relative low in April to the highest in August, and then decreased gradually. The characteristics of vertical section and temporal variation in soil organic carbon mineralization intensity were similar to that in soil organic carbon and active carbon, and significant changes only occurred on topsoil at 0-20 cm.[Conclusion] Soil organic carbon mineralization intensity is significantly influenced by microbe, temperature and carbon content, and this influence is more significant in soil carbon content.