Exploring the microbial mechanisms of organic matter transformation during pig manure composting amended with bean dregs and biochar.

This study researched the impacts of biochar (B) and bean dregs (BD) on organic matter degradation and humification, as well as the bacterial community and functional characteristics during pig manure (PM) composting. The temperature, pH, and dissolved organic carbon (DOC) were reached the maturity of compost. Results indicated that BD + B treatment promoted organic matter degradation and increased humic acid content by 19.5-25.1% from the control (CK). Additionally, the bacterial communities were determined by high-throughput sequencing, and their metabolic functions were evaluated through the phylogenetic investigation of communities by reconstructing unobserved states (PICRUSt). BD + B influenced the microbial community structure of compost, and the PICRUSt results indicated that BD + B strengthened the metabolism of carbohydrates and amino acids. Redundancy analysis (RDA) was conducted, and a positive correlation was observed between organic matter transformation and temperature, pH, DOC, and community structure. Therefore, regulating these compost properties can effectively promote organic matter transformation during composting.