Ammonia emissions from a beef cattle feedyard on the southern High Plains

Concentrated animal feeding operations (CAFOs) are major sources of ammonia into the atmosphere. There is considerable literature on ammonia emissions from and swine CAFO, but few comprehensive studies have investigated large open lot, cattle feedyards. Ammonia emission rates and emission factors for a 77-ha, commercial beef cattle feedyard on the southern High Plains were quantified measured profiles of ammonia concentration, wind speed and air temperature, inverse dispersion model. Mean summer emission rate was 7420 kg NH3 d(-1), and emission rate was about half that, at 3330 kg NH3 d(-1). Annual NH3-N emission rate 4430 kg NH3-N d(-1), which was 53% of the N fed to cattle. Daily per capita NH3-N increased by 10-64% after the daily per capita N in feed rations increased by Annual emission factors for the pen area of the feedyard were 19.3 kg NH3 (head fed)(-1), or 70.2 kg NH3 Mg-1 biomass produced. Annual emission factors for the retention of the feedyard were estimated to be 0.9 kg NH3 (head fed)(-1), or 3.2 kg NH3 Mg-1 produced. Published by Elsevier Ltd.