Effects of burning harvested residues on the archaeal and bacterial communities of Eucalyptus urophylla substituting native vegetation

The land preparation method of burning harvested residues considerably affects soil archaeal and bacterial communities. However, the changes in the archaeal and bacterial communities of Eucalyptus urophylla plantation and the driving factors of microbial community diversity are still unknown. This study explored the effects of E. urophylla replacement for native vegetation and the burning of harvested residues on the diversity of archaeal and bacterial communities. Soil samples were collected from the E. urophylla plantation with burnt (Burn) and retained (Retain) harvest residues after 5 years, and the native vegetation was selected as a control (CK). Results show that significant differences in soil organic matter, available phosphorus, available boron, soil bulk density, and moisture content were found among the three stands (p < 0.05), and the concentrations of OM, AP and AB in Burn are the lowest, and BD is the highest. CK has the highest diversity of archaeal and bacterial communities, whereas Burn has the lowest. The co-occurrence network pattern of CK shows high robustness and high positive interaction between archaea and bacteria. However, Burn's network shows extremely low robustness and high negative interaction. Available phosphorus, organic matter, and bulk density are the key factors affecting archaeal and bacterial communities as confirmed by random forest models, redundant analysis, and structural equation modeling. Furthermore, the influence of environmental factors on archaeal communities is greater than that on bacteria, and the total effect of environmental factors on bacteria through archaeal community mediation is significant, including 79.45% indirect effects. These results can serve as a reference to enhance the management of harvested residues in E. urophylla plantations in the future.