Ammonia emission factors from broiler litter in barns, in storage, and after land application

Abstract

We measured NH₃ emissions from litter in broiler houses, during storage, and after land application and conducted a mass balance of N in poultry houses. Four state-of-the-art tunnel-ventilated broiler houses in northwest Arkansas were equipped with NH₃ sensors, anemometers, and data loggers to continuously record NH₃ concentrations and ventilation for 1 yr. Gaseous fluxes of NH₃, N₂O, CH₄, and CO₂ from litter were measured. Nitrogen (N) inputs and outputs were quantified. Ammonia emissions during storage and after land application were measured. Ammonia emissions during the flock averaged approximately 15.2 kg per day-house (equivalent to 28.3 g NH₃per bird marketed). Emissions between flocks equaled 9.09 g NH₃ per bird. Hence, in-house NH₃ emissions were 37.5 g NH₃ per bird, or 14.5 g kg(-1) bird marketed (50-d-old birds). The mass balance study showed N inputs for the year to the four houses totaled 71,340 kg N, with inputs from bedding, chicks, and feed equal to 303, 602, and 70,435 kg, respectively (equivalent to 0.60, 1.19, and 139.56 g N per bird). Nitrogen outputs totaled 70,396 kg N. Annual N output from birds marketed, NH₃ emissions, litter or cake, mortality, and NO₂ emissions was 39,485, 15,571, 14,464, 635, and 241 kg N, respectively (equivalent to 78.2, 30.8, 28.7, 1.3, and 0.5 g N per bird). The percent N recovery for the N mass balance study was 98.8%. Ammonia emissions from stacked litter during a 16-d storage period were 172 g Mg(-1) litter, which is equivalent to 0.18 g NH₃ per bird. Ammonia losses from poultry litter broadcast to pastures were 34 kg N ha (equivalent to 15% of total N applied or 7.91 g NH₃ per bird). When the litter was incorporated into the pasture using a new knifing technique, NH₃ losses were virtually zero. The total NH₃ emission factor for broilers measured in this study, which includes losses in-house, during storage, and after land application, was 45.6 g NH₃ per bird marketed.