| الملخص: | Arbuscular mycorrhizal (AM) fungi can have complicated interactions with plants and soils, which play a critical role in mediating the soil carbon cycle. However, the mechanism by which AM fungi regulate soil respiration is not well documented. This study conducted a completely randomized block-design mesocosm experiment using the inoculation of AM fungi (RI: <i>Rhizophagus intraradices</i>; FM: <i>Funneliformis mosseae</i>) with <i>Fraxinus malacophylla</i> to identify the pathways of AM fungi controlling soil respiration in a rocky desertification habitat. We observed that the average soil respiration rates (3.78 μmol·m<sup>−2</sup>·s<sup>−1</sup>) were significantly higher in two AM fungi inoculation treatments than in the control (2.87 μmol·m<sup>−2</sup>·s<sup>−1</sup>). Soil respiration rates were 1.59-fold higher in RI fungi inoculation and 1.05-fold higher in FM inoculation than in the control. Explanation rates of microbial biomass carbon, biomass nitrogen, and root biomass in RI (57.46–76.49%) and FM (44.81–62.62%) inoculation for soil respiration variation were higher than those in the control (24.51–34.32%). The direct positive pathway of soil respiration was mainly regulated by microbial biomass (59.5%) and root biomass (34.90%), while the indirect positive contributions of soil physicochemical properties (30.00%), colonization level (3.50%), soil microclimate (19.30%), and enzyme activity (3.38%) to respiration dynamics ranked second. Thus, we conclude that soil respiration dynamics can be mainly controlled by AM fungi-mediated changes in microbial and root biomass in rocky desertification areas.
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