Submitted to: International Poultry Forum Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: January 24, 2005
Publication Date: January 24, 2005
Citation: Miles, D.M., Owens, P.R., Rowe, D.E. 2005. Winter gaseous flux from broiler litter for commercial broilers at placement, middle and end of flock [abstract]. International Poultry Scientific Forum Abstracts. p. 50.
In 2003, the National Research Council recommended a process-based, mass balance approach to estimate emissions. Empirical methods, such as the one described below, will form the basis of the desired models. The objective of this study was to characterize the variability of litter gas flux through a winter flock in a solid sidewall commercial broiler house. On d 2, 22, and 45, ammonia, nitrous oxide, and carbon dioxide concentrations were measured using a photoacoustic multigas analyzer and flux boxes. The 146 m by 12.8 m house was sampled on a grid at 5 m across the house and 12 m down the house (36 sampling points). Instantaneous flux measurements were estimated from the differences in time zero and one-minute concentrations using the ideal gas law. Litter temperature, air temperature and relative humidity were concurrently measured on the grid; litter was sampled at each site to determine litter pH and moisture. Ammonia flux on d 2 averaged 439 and 361 mg/(m2 hr) for the brood and vacant ends of the house. The greater flux in the brood area corresponds to higher litter and air temperature and low litter moisture. Flux for nitrous oxide and carbon dioxide were also greater in the brood area at d 2. At d 22, all gas fluxes were diminished along the center of the house and were elevated at the sidewalls. Ammonia flux on d 45 for the entire house averaged 694 mg/(m2 hr), and was accompanied by the lowest air temperatures, moderate litter temperatures, and the highest litter moistures. Litter ammonia flux increased only marginally from placement to mid-growout, but more rapidly from mid-flock to sell-age. Litter moisture was the only parameter to approximate this same trend. Bird age, or co-linear factors such as size, amount of deposition, and management, is a significant factor for the increase in litter gas flux during the winter and should be considered in comprehensive models for emission estimates.