ABSTRACT
This study aimed to clarify the effect of the integrated addition of different proportions of biochar (0 and 5%) and MnSO4 (0, 0.25%, and 0.50%) to pig manure compost. The results indicated the integrated use of biochar (BC) and Mn2+ advanced the compost humification. In particular, the integrated use of 0.50% Mn2+ and 5% BC showed higher total organic carbon degradation (20.67%) and humic acid production (81.26 g kg-1) than other treatments. Microbial community analysis showed the integrated use of BC and Mn2+ regulated the diversity and community structure of organic matter-mineralizing microbes by maintaining the relative abundance of bacteria Firmicutes (54.62%) and Proteobacteria (38.05%) at high levels during the thermophilic period and boosting those of the fungi of Ascomycota (58.91%) and Actinobacteria (15.60%) during the maturity period of composting. This study illustrated the potential and biological mechanisms of integrating BC and Mn2+ as additives in compost humification.