Review of ammonia and greenhouse gases emission factors from poultry housings: Influence of practices and rearing conditions

Ammonia (NH3) and greenhouse gases (GHGs) emissions are two major concerns of agricultural pollution because ammonia contributes to water and soil pollution (eutrophication and acidification) and GHGs are responsible for global warming and climate change. Poultry production is known, as other animal productions, to produce NH3 and GHGs and best management practices and optimal rearing conditions have to be identified in order to reduce the gaseous emissions. Understanding the determinism of gaseous emissions is the first step toward the conception of innovative systems or practices. This paper presents a review of NH3 and GHGs emission factors (EFs) from several studies with a focus on the influence of practices and rearing conditions on gaseous emissions. The analysis of the EFs shows that manure management (e.g. removal frequency or chemical treatment) is the main way to mitigate NH3 and GHGs emissions. Rearing conditions (mainly temperature) and flock management practices (e.g. dietary practices or flock density) also appear to be efficient ways to mitigate the emissions of NH3 and GHGs in poultry housings