Greenhouse Gas (GHG) Emissions from Broiler Houses in the Southeastern United States

摘要

Greenhouse gas (GHG) emissions, including carbon dioxide (CO_2), methane (CH_4) and nitrous oxide (N_2O), from broiler houses located in the southeastern United States were continuously monitored over a one-year period. The birds were grown to 52 daysof age at an average stocking density of 11.8 birds/m~2 (1.1 birds/ft~2). Methane and CO_2 emissions were measured in two broiler houses while N_2O emissions were measured in one house. Carbon dioxide and N_2O concentrations were measured using a photoacoustic multi-gas analyzer and CH_4 concentrations were measured using a dual-channel methane/non-methane-hydrocarbon (NMHC)/total hydrocarbon analyzer with dual flame ionization detectors. Ventilation rates in each house were continuously calculated bymonitoring the building static pressure and operational status of all ventilation fans in conjunction with individual fan performance curves developed and verified in situ using a Fan Assessment Numeration System (FANS) unit. Annual CO_2 emissions measured from the two broiler houses averaged 606 Mg (668 US tons) per house. On a marketed bird basis the CO_2 emissions averaged 4.64 Mg (5.49 US tons) per 1,000 birds marketed. Annual CH_4 emissions averaged 445 kg (982 lbs) per house, or 3.41 kg (7.52 lbs)per 1,000 birds marketed. Annual N_2O emissions measured from one broiler house was 225 kg (496 lbs) per house, or 1.72 kg (3.8 lbs) per 1,000 birds marketed. The CO_2 equivalents of the CH_4 and N_2O emissions were, respectively, 85.3 kg (188 lb) and 512.6 kg (1,128 lb) per 1,000 birds marketed. Hence the total CO_2 equivalent GHG emissions for the broiler operations monitored in this study were 5.238 Mg per 1,000 birds marketed, with 88.6% contributed by CO_2.