Diurnal and seasonal variations of greenhouse gas emissions from a commercial broiler barn and cage-layer barn in the Canadian Prairies

Abstract

Baseline emission values of greenhouse gases were not well established for commercial poultry barns in cold regions, including Canada, due to a lack of well-designed field studies. Emission factors of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), were acquired for a commercial broiler barn and cage-layer barn in the Canadian Prairies climate. Between March 2015 and February 2016, monthly measurements throughout the year for the layer barn and over 6 flocks for the broiler barn, and diurnal measurements in the mild, warm, and cold seasons for both barns were conducted, respectively. The ventilation rate was estimated based on a CO2 mass balance method; thus CO2 emissions were quantified by the CIGR (2002) models. The CH4 and N2O emissions present at low levels from global perspective for both barns; the cold climate proved to be a major reason for the lower CH4 emission from the layer barn. Considerable seasonal effect was observed only for N2O emissions from the broiler barn, and for CH4 and N2O emissions from the layer barn, both with higher emissions in the mild and warm seasons than in the cold season. The big diurnal variations of CO2 emissions for the layer barn demonstrated the uncertainty of the seasonal results by snapshot measurements and correction factors (from −20.9% to −22.5%) were obtained. Besides, the difference of CH4 and N2O concentrations and emissions as well as CO2 concentrations between best-case (the first day after manure removal) and worst-case conditions (the last day before manure removal) was not obvious for the layer barn. Additionally, changes of temperature and ventilation rate were likely to have more impact on N2O emission for the broiler barn and more impact on CH4 emission for the layer barn than on the other two gas emissions, both with positive correlations.