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(-1)kg(-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 O-2 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, O-2 and electrical conductivity were the key factors affecting the evolution of bacterial community. [GRAPHICS]