稻田土壤微生物残体积累对外源秸秆输入的响应研究进展

稻田土壤碳循环是我国陆地生态系统碳循环的重要组成部分。促进稻田生态系统碳的固定及稳定对减缓全球气候变化起着不容忽视的作用。微生物主导的有机碳转化过程是土壤碳循环研究的核心,微生物同化代谢介导的细胞残体迭代积累在土壤有机碳长期截获和稳定过程中发挥重要作用。与旱地土壤相比,关于稻田土壤中微生物残体积累动态对外源有机物质如作物秸秆输入的响应及主要影响因子的认识还相对有限,对微生物通过同化作用参与土壤固碳的过程和机制尚缺乏系统认识。基于此,本文介绍了微生物残体对土壤有机碳库形成和积累的重要性及评价指标,重点探讨了秸秆还田对稻田土壤微生物残体积累动态以及外源秸秆碳形成细胞残体转化过程的影响,分析了影响微生物残体积累转化的主要气候因素和土壤因素,最后提出了未来应借助先进的光谱和高分辨率成像技术并结合同位素示踪对微生物残体的稳定性与机理开展更为深入的研究。

Response of Soil Microbial Residue Accumulation in Paddy Soil to Straw Amendment: A Review

Carbon cycling in paddy soil is a crucial aspect of China''s terrestrial ecosystem carbon cycle. Promoting the sequestration and stabilization of soil organic carbon in paddy ecosystem plays a critical role in mitigating global climate change. Soil microorganisms are the primary drivers of carbon cycling. There is an increasing recognition of the critical role of microbial residues/necromass in long-term carbon sequestration and stabilization in soil. However, there are fewer investigations on how exogenous organic matter inputs, such as crop straw amendment, affect the accumulation dynamics of microbial necromass in paddy soils compared to those conducted on dryland soils. Additionally, there is a lack of systematic understanding of the process and mechanism by which microbes participate in soil carbon sequestration via microbial necromass production and accumulation in paddy ecosystem. Therefore, this review firstly introduces the importance of microbial residues in the formation and accumulation of soil organic carbon pools using amino sugar biomarkers. Then, it elaborates on the responsive dynamics and stocks of microbial necromass following rice straw amendment, as well as the incorporation of straw-carbon into microbial amino sugars in rice paddy soils. And it also analyzes the main climatic and edaphic factors controlling the transformation of microbial-derived carbon accumulation. Finally, it proposes that advanced spectroscopy and high-resolution imaging technology should be used in combination with isotope tracing to conduct more in-depth research on necromass stabilization mechanisms in future studies.