Evaluation of Alum Amendments of Poultry Litter on Reducing in-House Ammonia and Greenhouse Gas Concentrations and Emissions.

The real time effect of alum (Al₂(SO4)₃ ·14H₂O) addition to poultry litter on ammonia (NH₃) emissions from poultry houses has not been accurately evaluated. Further, its effects on greenhouse gas (GHG; N₂O, CH₄, and CO₂) emissions has not been assessed. We determined the effects of alum additions on: (i) in-house NH₃ and GHG concentrations, (ii) NH₃ and GHG emissions, and (iii) litter chemical properties. We continuously measured NH₃ and GHG concentrations using a photoacoustic multi-gas analyzer, as well as ventilation (air velocity) from two identical tunnel-ventilated broiler houses located in Northwest Arkansas; where one house was assigned as control and the other was chemically amended with alum in between flocks for three flocks of birds. Real time emission rates were determined by coupling gas concentrations with ventilation rates from each house. Results indicate that alum amendments significantly reduced daily average in-house NH₃ concentration by 42% (8.9 vs 15.4 uL L^-1), whereas the overall NH₃ emission rate was reduced by 47% (7.2 vs 13.4 kg day^-1 house^-1). The three flocks cumulatively averaged 330 kg NH₃ house^-1 flock^-1 for the alum-treated house and 617 kg NH₃ house^-1 flock^-1 for the control. Alum additions did not significantly affect the concentrations and emissions of N₂O and CH₄, whereas CO₂ emissions were significantly higher from the untreated house. Litter nitrogen (N) content was significant greater, while carbon (C) to N ratio was significantly lower with alum additions. While this study illustrates that alum addition to poultry litter is an effective management practice for reducing in-house NH₃ concentrations and emissions, its addition also contributes to the additional benefit of reducing CO₂ emissions from poultry facilities.