Effects of synthetic flora and additives on microbial community structure and carbon and nitrogen transformation in chicken manure composting process.

In this study, the effects of synthetic flora and ferrous sulfate-calcium superphosphate composite additives on the microbial community structure and carbon-nitrogen transformation during chicken-manure straw composting process were investigated. The results showed that the addition of synthetic flora significantly increased the abundance and diversity of the bacterial community, particularly the relative abundance of dominant phyla such as Firmicutes and Actinobacteria. Neutral community model (NCM) reveals that exogenous bacteriophages synergistically interact with chemical additives to shift microbial community assembly from a stochastic to a deterministic process. co-occurrence network analysis further demonstrated that the additives enhanced the compost maturation efficiency by increasing the complexity and stability of the microbial interactions networks. Environmental factor analyses revealed that temperature, pH and moisture were the key drivers of microbial community succession, with pH playing a particularly significant role in regulating bacterial and fungal diversity. Random forest and VPN analyses indicate the critical role of microbial-environmental interactions in the carbon and nitrogen cycling of compost. Additionally, functional prediction analysis indicated that the additive package reduced greenhouse gas (CH4, N2O) emissions and improved nitrogen retention efficiency by promoting the expression of genes associated with microbial carbon metabolism and nitrogen cycling. LEfSe (Linear Discriminant Analysis Effect Size) analyses showed that the complex additives significantly altered the microbial community structure and ecological functions.