The bacterial community drive the humification and greenhouse gas emissions during plant residues composting under different aeration rates.

This study investigated the effects of different aeration intensities on organic matter (OM) degradation, greenhouse gas emissions (GHG) as well as humification during plant residue composting. Three intermittent aeration intensities of 0.084 (T_low), 0.19 (T_medium) and 0.34 (T_high) L min^-1kg^-1 DM with 30 min on/30 min off were conducted on a lab-scale composting experiment. Results showed that OM mineralization in T_high was more evident than T_low and T_medium, resulting in the highest humic acid content. Humic acid content in T_medium and T_high was 15.7% and 18.5% higher than that in T_low. The average O₂ concentration was 4.9%, 9.5% and 13.6% for T_low, T_medium and T_high. Compared with T_medium and T_high, T_low reduced CO₂ and N₂O emissions by 18.3%-39.6% and 72.4%-63.9%, but the CH₄ emission was highest in T_low. But the total GHG emission was the lowest in T_high. Linear Discriminant Analysis Effect Size analysis showed that the core bacteria within T_low mainly belonged to Anaerolineaceae, which was significantly negatively correlated to the emission of CH₄. Thermostaphylospora, Unclassified_Vicinamibacteraceae and Sulfurifustis were identified as core bacteria in T_medium and T_high, and these genus were significantly postively correlated to CO₂ and N₂O emissions. Redundancy analysis showed that total orgnic carbon, O₂ and electrical conductivity were the key factors affecting the evolution of bacterial community.