News Release

MADISON, WI, DECEMBER 17, 2007 -- The ammonia given off from livestock manure into air is a major pathway of nitrogen movement between land and air. While in the atmosphere ammonia reacts with acids, which forms aerosols and can contribute to poor air visibility and impact human health. Atmospheric ammonia is eventually deposited to land and water bodies where it can lead to acid soil and mineralization of waterways (eutrophication), and can cause reduced diversity of the environment. It follows that there is a need to quantify the important sources of ammonia in agriculture in order to make sound decisions to reduce ammonia losses. A study addressing ammonia emissions from animal agriculture was published in the November-December issue of the Journal of Environmental Quality.

Work at Agriculture and Agri-Food Canada's Lethbridge Research Centre by the team lead by Sean McGinn, Research Scientist, and by the University of Alberta, has focused on measuring gas emissions from animal agriculture because of the intensity of the industry in Alberta, Canada. The work was funded by the National Agro-Environmental Standard Initiative (NAESI) and contributes directly to the Canadian government's ammonia inventory project.

The ammonia emitted from an entire feedlot was calculated using field measurements along with a model that describes the gaseous dispersion plume, based on wind measurements. "The ammonia emission was calculated using this modeled relationship and a measured ammonia concentration made within the plume," explains McGinn. The advantage of this approach was that it was non-intrusive, allowed near-continuous measurements, and spatially integrated the whole farm emission.

The amount of ammonia found in the study indicates a vast quantity of ammonia is generated from beef feedlots because of the size and intensity of these operations. Each day during the summer, upwards of 3 tonnes of ammonia was lost from a 22,500 head feedlot, which represented about 63% of the nitrogen consumed. McGinn adds, "As a result, feedlots are 'hot-spots' of ammonia emissions into the ecosystem." However, since cattle feedlots are a highly managed operation in terms of controlling feeding practices, it follows that mitigation from this type of operation, through the reduction of feed protein, may be a viable option for the industry.