Methane and carbon dioxide emission from two pig finishing barns

Agricultural activities are an important source of greenhouse gases. However, comprehensive, long-term, and high-quality measurement data of these gases are lacking. This article presents a field study of CH₄ and CO₂ emission from two 1100-head mechanically ventilated pig (Sus scrofa) finishing barns (B1 and B2) with shallow manure flushing systems and propane space heaters from August 2002 to July 2003 in northern Missouri. Barn 2 was treated with soybean oil sprinkling, misting essential oils, and misting essential oils with water to reduce air pollutant emissions. Only days with CDFB (complete-data-full-barn), defined as >80% of valid data during a day with >80% pigs in the barns, were used. The CH₄ average daily mean (ADM) emission rates were 36.2 ± 2.0 g/d AU (ADM ± 95% confidence interval; animal unit = 500 kg live mass) from B1 (CDFB days = 134) and 28.8 ± 1.8 g/d AU from B2 (CDFB days = 131). The CO₂ ADM emission rates were 17.5 ± 0.8 kg/d AU from B1 (CDFB days = 146) and 14.2 ± 0.6 kg/d AU from B2 (CDFB days = 137). The treated barn reduced CH₄ emission by 20% (P < 0.01) and CO₂ emission by 19% (P < 0.01). The CH₄ and CO₂ released from the flushing lagoon effluent were equivalent to 9.8 and 4.1% of the CDFB CH₄ and CO₂ emissions, respectively. The emission data were compared with the literature, and the characteristics of CH₄ and CO₂ concentrations and emissions were discussed.