Journal of Integrative Agriculture ›› 2026, Vol. 25 ›› Issue (7): 3044-3057.DOI: 10.1016/j.jia.2025.12.030

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不同草地管理下三库土壤有机碳矿化的趋同动态与共享机制

  

  • 收稿日期:2025-05-12 修回日期:2025-12-18 接受日期:2025-10-30 出版日期:2026-07-20 发布日期:2026-06-09

Convergent dynamics and shared mechanisms of three-pool soil carbon mineralization under different grassland managements

Junhao Feng1*, Ji Chen2*, Xiaowei Liu3, Yudu Jing4, 5, 6, Ke Liang3, Qiang Yu5, 7, Changhui Peng8, 9, Liang Guo7, 10, 11#   

  1. 1 State Key Laboratory of Soil and Water Conservation and Desertification Control, College of Soil and Water Conservation Science and Engineering, Northwest A&F University, Yangling 712100, China

    2 State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710061, China

    3 College of Grassland Agriculture, Northwest A&F University, Yangling 712100, China

    4 The Research Center for Soil and Water Conservation and Ecological Environment, Chinese Academy of Sciences and Ministry of Education, Yangling 712100, China

    5 Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, China

    6 University of Chinese Academy of Sciences, Beijing 100049, China

    7 State Key Laboratory of Soil and Water Conservation and Desertification Control, Northwest A&F University, Yangling 712100, China

    8 School of Geographic Sciences, Hunan Normal University, Changsha 410081, China

    9 Department of Biology Science, Institute of Environment Sciences, University of Quebec at Montreal, Montreal H3C3P8, Canada

    10 Key Laboratory of the Alpine Grassland Ecology in the Three Rivers Region (Qinghai University), Ministry of Education, Xining 810016, China

    11 Administration Bureau of Ningxia Yunwushan National Nature Reserve, Guyuan 756000, China

  • Received:2025-05-12 Revised:2025-12-18 Accepted:2025-10-30 Online:2026-07-20 Published:2026-06-09
  • About author:#Correspondence Liang Guo, Mobile: +86-18709221128, E-mail: guoliang2014@nwafu.edu.cn * These authors contributed equally to this study.
  • Supported by:

    This study was funded by the National Natural Science Foundation of China (42377471), the Natural Science Foundation of Ningxia Hui Autonomous Region, China (2024A AC05099), and the Open Project of Key Laboratory of the Alpine Grassland Ecology in the Three Rivers Region (2023-SJY-KF-04) from Qinghai University, China.

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摘要：

草地土壤有机碳（SOC）的矿化动态对陆地生物地球化学循环至关重要。然而，不同碳库的SOC矿化过程如何受到胞外酶代谢与微生物群落结构的调控仍不清楚。本研究通过553天的室内培养实验，探究了封育与放牧草地土壤CO2排放、胞外酶活性、微生物生物量及群落组成随时间变化特征。基于三库模型，我们量化了活性、缓效及惰性碳库的SOC矿化动态，揭示了在长期碳周转过程中，矿化主导地位从活性碳库向惰性碳库转移的趋势，并受草地管理措施影响。与放牧草地相比，封育草地的活性碳库规模约高110%，且初期SOC矿化速率更高（培养前113天显著偏高），但两种管理方式下微生物与酶的长期调控机制—尤其是微生物策略的转变、酶活性模式及其与碳库的相互作用—表现出高度的相似性。碳库动态的转变源于微生物分解惰性碳能力的增强，该过程伴随氧化酶产量显著提升（如封育和放牧土壤中质量比氧化酶活性分别增加190.6%和256.1%）以及氮、磷需求升高。值得注意的是，微生物群落由快速生长的富营养型类群（如变形菌门、拟杆菌门、子囊菌门）逐渐向慢速生长的寡营养型类群（如酸杆菌门、放线菌门、浮霉菌门、担子菌门）转变，细菌与真菌的寡/富营养型比率分别上升55.5–62.6%和96.9–247.5%，且与酶活性及化学计量比变化密切相关。本研究从机制层面阐明了不同草地管理模式下，微生物生态策略与酶活性如何协同调控各碳库的SOC矿化过程，为深化SOC周转认知、提升碳循环预测能力提供理论依据，对全球气候变化反馈研究具有重要意义。

Abstract:

The mineralization dynamics of soil organic carbon (SOC) in grasslands are crucial to terrestrial biogeochemical cycles.  However, the regulatory mechanisms underlying extracellular enzyme metabolism and microbial community structure during SOC mineralization across different carbon pools remain poorly understood.  In this study, a 553-day incubation experiment was conducted to examine temporal changes in CO2 emissions, extracellular enzyme activities, microbial biomass, and microbial community composition in soils from both enclosed and grazed grasslands.  Using a three-pool model, SOC dynamics were quantified within active, slow, and passive carbon pools, revealing a shift in the dominance of mineralization from the active carbon pool to the passive carbon pool during the long-term carbon turnover, with differences observed across grassland management strategies.  Compared to grazed grasslands, enclosed grasslands exhibited an approximately 110% larger active carbon pool and higher initial SOC mineralization rates (significantly higher during the first 113 days), yet long-term microbial and enzymatic regulatory mechanisms - particularly shifts in microbial strategies, enzyme activity patterns, and their interactions with carbon pools - were similar across both management regimes.  The observed shifts in carbon pool dynamics were driven by enhanced microbial capacity to decompose passive carbon, associated with substantially increased oxidative enzyme production (e.g., mass-specific oxidase activity increased by 190.6% in enclosed soil and by 256.1% in grazed soil) and elevated nitrogen and phosphorus demands.  Notably, microbial communities shifted from fast-growing copiotrophic taxa (e.g., Proteobacteria, Bacteroidetes, Ascomycota) to slower-growing oligotrophic taxa (e.g., Acidobacteria, Actinobacteria, Planctomycetes, Basidiomycota), with the oligotroph-to-copiotroph ratio increasing by 55.5–62.6% for bacteria and 96.9–247.5% for fungi.  These changes were closely linked to shifts in enzyme activity profiles and stoichiometric ratios.  Overall, this study provides mechanistic insights into how microbial ecological strategies and enzyme activities interact to regulate SOC mineralization across different pools under contrasting grassland management regimes.  These findings advance our understanding of SOC turnover and improve predictive capabilities for carbon cycling, with broader implications for global climate change feedbacks.

Key words: soil organic carbon mineralization , soil respiration , three-pool model , microbial community , extracellular enzyme , incubation experiment , grasslands