Mitigating ammonia emissions from typical broiler and layer manure management – A system analysis

Broiler and layer productions are important ammonia (NH3) emission sources in the livestock industry. Here, we present the first meta-analysis and integrated assessment of NH3 emissions and mitigation potentials for typical broiler litter manure management system (MMS) and layer manure belt MMS based on data from 96 studies. A total of 10 integrated NH3 emission factors (EFs) and the NH3 mitigation efficiencies (MEs) of 14 available options were provided. The estimated NH3 emissions from the baseline scenarios of the broiler litter MMS and the layer manure belt MMS were 84.1 ± 5.9 kg AU−1 yr−1 and 53.5 ± 15.8 kg AU−1 yr−1, respectively. The NH3 mitigation for the broiler litter MMS should be focused on the in-house stage, while the mitigation in the layer manure belt MMS should be focused on the outdoor and land application stages. The recommended NH3 mitigation options for the in-house stage, the outdoor stage and the land application stage were acid scrubber (−92.5%), compost biofilter (−71.9%) and changing the manure surface application to incorporation (−83.0%), respectively. The recommended mitigation combinations of low crude protein (LCP) diet, acid scrubber, compost biofilter and manure incorporation achieved the highest NH3 mitigation efficiency from both broiler litter MMS and layer manure belt MMS, by 89.3% and 84.8%, respectively. The results of this study have important implications for developing sustainable poultry production systems from the viewpoint of NH3 mitigation. The environment issues such as the other reactive nitrogen emissions and the greenhouse gas (GHG) emissions should also be considered in the future.