Soil organic carbon (SOC) is the core component of terrestrial carbon (C) sink. Exploring the transformation and stabilization mechanism of SOC is key to understand the function of terrestrial C sink which copes with climate change. The traditional perspective is that plant residues are the initial source of SOC. The new concept of "soil microbial C pump" emphasizes that the synthesized products of soil microbial assimilation are important contributors to the stable SOC. This provides a new insight to the sequestration mechanism of SOC. Due to the complex and variable decomposition process of plant residues and the high heterogeneity of microbial residues, the transformation and stabilization mechanism of plant residues and microbial residues into SOC is still unclear. We reviewed research progress in plant and microbial residues, and introduced the characterization methods of quantification and transformation of plant residues and microbial residues, and also summarized the new findings on the transformation of plant and microbial residues into SOC. We further discussed the contribution and driving factors of microbial and plant-derived C to SOC. Finally, we prospected the future development direction and research focus in this field. This review would provide the scientific reference for the research of soil C sequestration in terrestrial ecosystem.
土壤有机碳库是陆地生态系统碳汇的重要组成部分,探明土壤有机碳的转化与稳定机制是深入理解陆地生态系统碳汇功能及应对气候变化的关键。近年提出的“土壤微生物碳泵”理论,即:植物残体是土壤有机碳的初始来源,微生物同化产物也是土壤稳定有机碳库的重要贡献者,对土壤有机碳的固存机制提出了新的见解。由于植物残体分解过程的复杂性、多变性以及参与分解过程的微生物种群的高异质性,植物残体和微生物残体向土壤有机碳的转化和稳定机理尚不十分明确。本文阐述了植物残体和微生物残体定量的表征方法以及它们在土壤中的稳定机制,探讨了植物和微生物源残体碳对土壤有机碳的贡献及其在土壤有机碳积累过程中的主要影响因素,最后对该研究领域未来的发展方向和研究重点进行展望,以期为陆地生态系统土壤固碳研究提供科学支撑。.
Keywords: microbial carbon pump; microbial residue; plant residue; soil microbe; soil organic carbon.