Greenhouse gas emissions from beef cattle pen surfaces in North Dakota

There is a global interest to quantify and mitigate greenhouse gas (GHG) (e.g. methane-CH4, nitrous oxide-N2O and carbon dioxide-CO2) emissions in animal feeding operations. The goal of this study was to quantify GHG emissions from the feedlot pen surface under North Dakota climatic conditions. In this study gaseous flux from the pen surfaces was generated using a custom-made wind tunnel at different times of the year (summer, fall, winter and spring). Gaseous fluxes (air samples) were drawn in the Tedlar bags using a vacuum chamber and gas concentrations were measured using a gas chromatograph within 24 h of sampling. The CH4 concentrations and flux rates (FRs) or flux among the months were not significantly different. Overall CH4, CO2 and N2O concentrations over a 7-month period were 2.66, 452 and 0.67 ppm, respectively. Estimated overall CH4, CO and N2O FRs were 1.32, 602 and 0.90 g m(-2) d(-1), respectively. Estimated emission rates using the wind tunnel were 38 g hd(-1) d(-1), 17 kg hd(-1) d(-1) and 26 g hd(-1) d(-1) for CH4, CO2 and N2O, respectively. The emission factors for GHG estimated in the research for North Dakota climate were the first of its kind, and these emission estimates can be used as a basis for planning and implementing management practices to minimize GHG emissions.