Modelling monthly NH3 emissions from dairy in 12 Ecoregions of Canada

Sheppard, S. C., Bittman, S., Swift, M. L. and Tait, J. 2011. Modelling monthly NH 3 emissions from dairy in 12 Ecoregions of Canada. Can. J. Anim. Sci. 91: 649-661. Ammonia (NH3) from livestock manure is emitted from barns, storages and manured land, and is a loss to the farm operations, while atmospheric NH3 has potential impacts beyond the farm, including human health and ecological damage. Models are used to estimate the intensity and spatial extent of NH3 emissions, and this paper reports a recent model developed for quantifying emissions from the dairy sector in Canada. The estimated overall average emission to the atmosphere in Canada in 2006 was 42.4±9.0 kg NH3 cow-1 yr-1 from a lactating cow, and total emission from the Canadian dairy sector was 56000 t NH3. On many farms the NH3 emissions may have been a significant portion of the N requirements of their crops. The emission estimates in the 12 Ecoregions were proportional to the animal census. Emissions generally peaked in May, mainly because of...