Intensive management enhances mycorrhizal respiration but decreases free-living microbial respiration through its effect on microbial abundance and community in Moso bamboo forests

Intensive management is known to markedly alter soil carbon (C) storage and turnover in Moso bamboo forests compared to extensive treatment regimes. However, the effect of intensive management on soil respiration (RS) components is still unclear. This study aimed to evaluate the changes in different RS components (root, mycorrhiza, and microbes) in Moso bamboo forests under extensive and intensive management practices. A one-year in-situ microcosm experiment was carried out to quantify the RS components in Moso bamboo forests under the two management approaches using mesh screens of varying sizes. The result showed that total RS and its components exhibited similar seasonal variability between the two groups. Compared to extensive management, intensive management significantly increased cumulative respiration from mycorrhizal fungi by 36.73% while decreasing cumulative respiration from free-living soil microbes by 8.97%. Moreover, the abundance of arbuscular mycorrhizal fungi (AMF) increased by 43.38%. In contrast, bacterial and fungal abundance decreased by 21.65% and 33.30% under intensive management. Both management practices significantly changed the bacterial community composition, which could be mainly explained by soil pH and available K. Mycorrhizal fungi and intensive management affected the co-occurrence interrelationships between bacterial members. Structural equation modeling indicated that intensive management changed the cumulative soil respiration via elevating AMF abundance and lowering bacterial abundance. We conclude that intensive management reduced the microbial respiration-derived C loss and increased the mycorrhizal respiration-derived C loss.