Automated Closed Chamber-Based Measurements of CO2, CH4 and NH3 Emissions from Fresh, Dried and Sludged Dairy Cattle Manure.

Deposition, storage and disposal of cattle manure is an integral part of animal feeding operations throughout the world.  Emissions of regulated and greenhouse gases from dairy manure contribute to air pollution and the global warming potential. Quantifying gas emission rates from various manure sources is essential for characterizing point-source contributions. A GASMET field-portable FTIR gas analyzer coupled with a custom-built automated closed chamber system was applied to continuously measure CO₂, CH₄ and NH₃ emissions from fresh and dried manure as well as from manure sludge. Other gasses including N₂O were not detectable at the ppm resolution of the analyzer. Measurements made over 30 days showed peak emissions 2-3 days after disturbance and deposition of samples. Peak emission rates of CO₂, CH₄ and NH₃ were 441, 1.68, and 2.60, respectively, while longer-term minimum rates were, 25.8, 0.013, and 0.005 g m^-2 d^-1 respectively. Cumulative month-long emissions of CO₂, CH₄ and NH₃ were 2550, 1.80, and 2.61 g m^-2 month^-1, respectively in May 2014. Based on these estimates, areal emissions from dairy feedlots and contributing areas of fresh and dried dairy manure can be estimated. Additional measurements under different seasonal temperature regimes are needed to better estimate annual emission rates and totals.