71 / 2023-05-31 23:26:44

Mature compost addition improves degradation efficiency and accelerates composting process by affecting the core microbial community during sorghum straw composting

sorghum straw; composting; mature compost addition; bacterial community

Sorghum straw (SS) is one of the main by-products generated every year from the Chinese liquor industry. 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 distiller's grains mature compost (DG) and microbial agent (MA) on SS composting physicochemical properties, 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 (M2) and MA (M3), compared with the control (M1). Both additives could improve the seed germination index (GI) of end-products (M2: 200.74% > M3:182.88 > M1:164.72%). Microbial analysis showed that two additives could increase the richness and diversity of bacterial community. The addition of DG significantly increased the abundance of Thermobifida、Lysinibacillus、Saccharopolyspora and unclassified_o__Bacillales, promoted the succession of microbial communities, and accelerated the composting process into the maturation stage. Network analysis showed that pH, MC, DOC, NH₄⁺, NO₃⁻ and GI could significantly affect the bacterial community. Prediction analysis showed that the addition of DG increased the relative abundance of Metabolism during composting. Above all, these results revealed the potential influence mechanism of additives on microbial community structure succession and metabolic function during SS composting.