Journal of Integrative Agriculture ›› 2025, Vol. 24 ›› Issue (3): 913-924.DOI: 10.1016/j.jia.2024.08.024

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围封禁牧丰富了藏北高寒草原丛枝菌根真菌群落 从而促进土壤有机碳固存

  

  • 收稿日期:2024-05-13 接受日期:2024-07-10 出版日期:2025-03-20 发布日期:2025-02-28

Grazing exclusion enriches arbuscular mycorrhizal fungal communities and improves soil organic carbon sequestration in the alpine steppe of northern Xizang

Yu Tang1, Chunhan Zhou1, Keyu Chen1, Sen Xing1, Hailan Shi1, Congcong Li1, Yanfen Wang2, Xiaoyong Cui3, Haishan Niu2, Baoming Ji1, Jing Zhang1#   

  1. 1 School of Grassland Science, Beijing Forestry University, Beijing 100083, China

    2 College of Resource and Environment, University of Chinese Academy of Sciences, Beijing 100049, China

    3 College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China

  • Received:2024-05-13 Accepted:2024-07-10 Online:2025-03-20 Published:2025-02-28
  • About author:Yu Tang, Mobile: +86-13378119583, E-mail: ty819@bjfu.edu.cn; #Correspondence Jing Zhang, Mobile: +86-18811622371, E-mail: zhangjing_2019@bjfu.edu.cn
  • Supported by:
    This work was supported by the Second Tibetan Plateau Scientific Expedition and Research Program, China (2019QZKK0304) and the National Natural Science Foundation of China (31800380 and 31761123001-1).

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摘要：

围封禁牧是退化高寒草原传统而有效的自然恢复方式，可有效促进植物生长和提高土壤碳储量。丛枝菌根真菌（AMF）是草地中不可或缺的重要微生物，在植物碳向土壤碳转化过程中发挥着重要作用。然而，围封对AMF群落的影响及其对土壤碳固存的贡献尚不清楚。本研究在藏北高寒草原选择了三种不同的围封禁牧时期（自由放牧、5-6年的中期围封和10年以上的长期围封），探讨了围封禁牧对AMF群落的影响及其在土壤固碳中的作用。结果表明，中期和长期围封都能显著增加植物地上生物量和土壤有机碳（SOC）含量。在不同的围封时期，AMF群落组成发生显著变化，随着围封时间的增加，Glomus的相对丰度显著增加，但Diversispora的相对丰度显著下降。中期围封显著增加了AMF的丰富度和香农-维纳指数。同时，围封还能显著提高菌丝密度（HLD）、球囊霉素相关土壤蛋白（GRSP）和土壤大团聚体（250-2000 μm）的比例，这些指标都对土壤碳固存有着积极的作用。结构方程模型显示：围封禁牧对HLD和AMF群落组成有积极影响，进而影响T-GRSP，而T-GRSP与SOC紧密相关。我们的研究结果表明，AMF对有机碳固存具有重要贡献，在高寒草原围封禁牧过程中应更多地关注AMF，尤其是在提高退化草地恢复效率的相关方面。

Abstract:

Fencing for grazing exclusion is regarded as a traditional and effective method for the natural restoration of degraded alpine steppe, and it effectively promotes plant growth and enhances soil carbon stocks.  Arbuscular mycorrhizal fungi (AMF) are essential microorganisms in grassland that play a major role in plant-derived C translocation into the soil.  However, the effects of fencing on AMF communities and their contributions to soil carbon sequestration are still unclear.  In this study, alpine steppe areas with three different fencing durations (free grazing, medium-term fencing for 5–6 years and long-term fencing for more than 10 years) in the northern Tibetan Plateau were selected to explore the effects of grazing exclusion on AMF communities and their roles in soil carbon sequestration.  The results showed that medium- and long-term fencing significantly increased both plant aboveground biomass and soil organic carbon (SOC) content.  The AMF community composition varied significantly during different fencing durations, with a dramatic increase in the relative abundance of Glomus but a significant reduction in the relative abundance of Diversispora with longer fencing time.  Medium-term fencing significantly increased AMF richness and the Shannon-Wiener index.  Meanwhile, fencing significantly increased hyphal length density (HLD), glomalin-related soil protein (GRSP) and the proportion of macroaggregates (250–2,000 μm), all of which contribute positively to SOC.  Structural equation modeling revealed that fencing time positively influenced HLD and the AMF community composition, subsequently affecting T-GRSP, which was tightly correlated with SOC.  Our findings suggest the potentially important contribution of AMF to SOC sequestration, so more attention should be paid to AMF during alpine steppe fencing, particularly for enhancing the efficiency of degraded grassland restoration efforts.


Key words: grazing exclusion , arbuscular mycorrhizal fungi ,  GRSP ,  SOC