Acta Agrestia Sinica

Acta Agrestia Sinica ›› 2026, Vol. 34 ›› Issue (7): 2341-2354.DOI: 10.11733/j.issn.1007-0435.2026.07.001

   

Effects of Grassland Degradation on Soil Carbon Cycle， Microbial Functional Genes and Metabolism

DING Cheng-xiang1, LI Xing-fu2, SU De-rong3, LIU Yu4   

  1. 1. Qinghai University, Xining, Qinghai Province 810016, China;
    2. Institute of Industrial Development Planning, National Forestry and Grassland Administration, Beijing 100010, China;
    3. Beijing Forestry University, Beijing 100083, China;
    4. Chinese Research Academy of Environmental Sciences, Beijing 100012, China
  • Received:2026-02-09 Revised:2026-03-30 Published:2026-07-02

草地退化对土壤碳循环、微生物功能基因及代谢的影响

丁成翔1, 李兴福2, 苏德荣3, 刘禹4   

  1. 1. 青海大学, 青海 西宁 810016;
    2. 国家林业和草原局产业发展规划院, 北京 100010;
    3. 北京林业大学, 北京 100083;
    4. 中国环境科学研究院, 北京 100012
  • 通讯作者: 刘禹，E-mail:lyu@craes.org.cn
  • 作者简介:丁成翔（1980-），男，回族，宁夏中卫人，博士，主要从事草地生态学研究，E-mail:2011990016@qhu.edu.cn
  • 基金资助:
    青海省中央引导地方科技发展资金项目（2024ZY011）；青海省重点研发与转化计划科技成果转化专项项目（2024-NK-138）；中央级公益性科研院所基本科研业务费青年探索项目（2025YSKY-39）资助

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Abstract: Under the context of global climate change， the influence mechanism of grassland degradation on soil carbon cycling remain poorly understood. In this study， we investigated 15 paired degraded and non-degraded grassland sites on the Qinghai-Tibet Plateau， integrated microcosm incubation， metagenomics and metabolomics to assess the impacts of degradation on key carbon cycling processes， organic carbon fractions， microbial functional genes， and metabolic intermediates. The results showed that grassland degradation significantly reduced labile carbon pools， with particulate organic carbon， dissolved organic carbon， and microbial biomass carbon decreasing by 48.21%， 30.87%， and 20.21%， respectively. Meanwhile， soil organic carbon mineralization increased by 56.71%， and carbon accumulation efficiency declined by 32.51%. Degradation also led to a decrease in the diversity of carbon cycling functional genes （-2.95%， P<0.05）， while the abundance of starch-degrading genes and carbohydrate-related metabolites increased significantly （by 9.39% and 49.6%， respectively）. These changes indicated that intensified microbial carbon limitation and a shift in metabolic strategy from synthesis to decoomposition. This study elucidates the key mechanisms underlying soil carbon cycling responses to grassland degradation from a multi-factor coupling perspective， revealing that environmental factors and microbial traits jointly regulated carbon cycling， with microbial functional genes and metabolic intermediates playing a dominat role.

Key words: Soil carbon cycling, Alpine grassland, Qinghai-Xizang Plateau, Grassland degradation, Functional genes, Microbial metabolism

摘要： 在全球气候变化背景下，草地退化对土壤碳循环的影响机制仍缺乏系统认知。本研究以青藏高原15对未退化—退化配对样地为对象，结合微宇宙培养、宏基因组与宏代谢组分析，综合评估退化对土壤碳循环关键过程、有机碳组分、微生物功能基因及代谢产物的影响。结果表明：草地退化显著降低活性碳库（颗粒有机碳、溶解性有机碳和微生物生物量碳分别下降48.21%、30.87%和20.21%），同时增强有机碳矿化（提高56.71%），降低碳积累效率（下降32.51%）。退化还导致碳循环功能基因多样性下降（-2.95%，P<0.05），但淀粉分解基因及碳水化合物代谢产物显著增加（分别上升9.39%和49.6%，P<0.05），表明微生物碳限制加剧，代谢策略由合成向分解转变。本研究从多要素耦合视角阐明了草地退化调控土壤碳循环的关键机制，表明环境因子与微生物特征协同驱动碳循环变化，其中微生物功能基因与代谢产物发挥主导作用。

关键词: 土壤碳循环, 高寒草地, 青藏高原, 草地退化, 功能基因, 微生物代谢

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