Housing emissions of NH3, N2O and CH4 and outdoor emissions of CH4 and N2O from organic broilers
Résumé
This study presents an assessment of gaseous emissions from an organic broiler production system composed of a broiler house and an outdoor run. In the house, concentrations of NH3, N2O, CH4, CO2 and H2O were monitored during 56 days over 3 discontinuous periods. To assess gaseous emissions, both indoor and outdoor gas concentrations were monitored using a photo-acoustic infrared analyser (INNOVA 1312). Air flow rates were estimated using SF6 tracer gas. Mass balances were also performed with zootechnical data to validate the
measurements and interpolate data between measurement periods. Outdoor N2O and CH4 emissions were measured using manual static chambers placed on the outdoor run. In the house, emissions were 130 mg NH3 day-1 broiler-1, 46 mg N2O day-1 broiler-1 and 13 mg CH4 day-1 broiler-1 . Indoor NH3 emissions were lower than for broilers raised in confinement, which can be explained by the access to the outdoor run. On the outdoor run, emissions of N2O and CH4 were low and close to background fluxes (< 40 ng s-1 m-2). Emission peaks were
occasionally detected, especially in chambers close to the house where the density of droppings was higher. With good assessment of dropping distribution on the outdoor run, emissions of CH4 and N2O could be extrapolated over the whole rearing period at the outdoor run scale