Effectiveness of two-stage inoculation of <i>Bacillus subtilis</i> and <i>Bacillus megaterium</i> on nitrogen transformation and microbial community in cow manure composting under low temperatures

This study addresses key challenges in low-temperature composting and provides solutions for cold-region agricultural sustainability and waste management. Using two-stage inoculation of a psychrophilic microbial consortium agent (New-Cold adapted Microbial Consortium Agent [NCMCA], <i>Bacillus subtilis</i>, and <i>Bacillus megaterium</i>), during cow manure composting under 1.2°C-12.6°C provides significant performance improvement. NCMCA doubles thermophilic phase duration, elevates peak temperatures, and accelerates decomposition, overcoming cold-induced microbial inhibition. Notably, it reduces NH₃ emissions by 11.82%, increases total nitrogen and nitrate levels, boosts compost quality, and mitigates environmental risks. By revealing how the NCMCA modulates microbial communities to promote nutrient cycling, this cost-effective strategy advances sustainable waste treatment in cold climates, supporting eco-friendly agriculture.