Study of the Relationship Between Nitrogen, Phosphorus Content, and Microbial Community Changes in Deer Manure Compost with Different Conditioners

Composting is an environmentally friendly method for disposing of solid waste. To enhance the fermentation rate and quality of deer manure composting, we investigated the effects of various conditioners (biochar, zeolite, biochar + zeolite) on the aerobic composting process of deer manure. The results indicated that the combination of biochar and zeolite significantly promoted the degradation of organic matter, resulting in a 34.83% decrease in total organic carbon (TOC) content. The addition of biochar was particularly beneficial for nitrogen retention in the compost, with the total nitrogen content reaching its highest level at 39.55 g/kg. Furthermore, the inclusion of zeolite and biochar altered the phosphorus content of the compost, with zeolite demonstrating a more favorable effect. The addition of a conditioner increased the relative abundance of Ascomycota and Proteobacteria and decreased the relative abundance of Firmicutes; the changes in Corynebacterium, Acinetobacter, and Glutamicibacter were positively correlated with the changes in the carbon-to-nitrogen ratio (C/N ratio) and negatively correlated with total nitrogen (TN) and total phosphorus (TP) levels. The mixed conditioner of biochar + zeolite used in composting exhibited low toxicity and the highest degree of decomposition. In summary, the combination of biochar + zeolite as a mixed conditioner is the optimal choice for reducing the toxicity of compost and promoting its maturation. Further research will be conducted in the future to promote the resource utilization of agricultural wastes such as deer manure.