A comparative study of composting sorghum straw inoculated with mature compost or commercial agents

Sorghum straw is one of the main by-products from the sorghum cultivation field for brewing and feeding. Composting can rapidly mineralize and humify SS into stable end-products by microbial metabolism, which can be used as organic fertilizers in soil. This study investigated the impact of mature compost and microbial agent on SS composting physicochemical properties, and the dynamic change in structure and potential function of bacterial community. The results showed that VS degradation efficiency increased by 30.34% and 20.27% respectively by adding DG and MA, compared with the control. Both additives could improve the seed germination index of end-products. Microbial analysis showed that two additives increaseed the richness and diversity of bacterial community. The addition of DG significantly increased the abundance of Thermobifida, Lysinibacillus, Saccharopolyspora and unclassified Bacillales, promoted the succession of microbial communities, and accelerated the composting process into the maturation stage. Network analysis indicated close correlation of pH, MC, DOC, NH4, NO3 and GI and the bacterial community. Prediction analysis showed that the addition of DG increased the relative abundance of metabolism pathway during composting. Above all, these results revealed the potential influence mechanism of additives on microbial community structure succession and metabolic function during SS composting.