Monthly NH3 emissions from poultry in 12 Ecoregions of Canada

Sheppard, S.C., Bittman, S. and Tait, J. 2009. Monthly NH3 emissions from poultry in 12 Ecoregions of Canada. Can J. Anim. Sci. 89: 21 35. Management of ammonia (NH3) is a multi-faceted issue for farmers. It is simultaneously a toxicant that can affect farm-worker and animal health, volatile plant nutrient that is expensive to replace if lost, and a potential contributor to environmental degradation. The environmental implications have important spatial and temporal dimensions, beyond the farm. This paper describes a model development to estimate NH3 emissions from poultry (broiler, layer and turkey) production in 2780 mapping units across Canada on a monthly time scale. It includes estimates of daily emission peaks within critical months. The results will contribute to estimates of haze and atmospheric aerosol production, as well as contriubutions to other potential impacts such as eutrophication of sensitive ecosystems. The model is based on a detailed survey of farm practices. Emissions vary strongly throughout the year, and in many regions there are peak emissions in early spring and late fall, associated with landspreading of manure. There are also markedly different nitrogen excretion rates among regions, and these and bird populations are the key factors controlling emissions. On average, 22% of excreted uric acid or ammoniacal N is emitted from barns, 2% from storage and 26% from landspreading, resulting in a total loss of 50%.