Comprehensive Effects of Aeration Rates on Ammonia Emissions, Nitrogen Transformation, and Compost Quality During Aerobic Composting of Chicken Manure

To mitigate severe nitrogen loss and elucidate the mechanisms of ammonia (NH3) reduction during aerobic composting of chicken manure, this study evaluated three aeration rates: A1 (0.2), A2 (0.6), and A3 (1.0 L min−1 kg−1). The results indicated that all treatments achieved standard harmlessness, with the thermophilic phase lasting 8–14 days and germination indexes exceeding 80%. Distinct performance trade-offs were observed across treatments. The A2 treatment achieved the highest maturity (GI: 100.81%) and the most stable process (indicated by the minimum redundancy analysis ellipse area), but concurrently yielded the maximum cumulative NH3 emissions (1074.88 g m−2). Conversely, the A3 treatment significantly suppressed cumulative NH3 emissions to 531.12 g m−2 (a 50.6% reduction compared to A2), driven primarily by moisture content (ρ = 0.99, p < 0.01), though this reduction occurred at the expense of system stability and microbial activity. Consequently, the selection of aeration rates requires a strategic trade-off tailored to specific goals: A2 is recommended for prioritizing premium-grade compost, whereas A3 is preferable for emission-driven scenarios. This study clarifies the aeration-mediated trade-off between NH3 mitigation and compost quality, providing a multi-objective decision-making framework for process optimization.