Emissions of Carbon Dioxide, Methane and Ammonia From Dairy Feces and Manure.

Gaseous emissions from animal manure are controversial sources for greenhouse gas emissions and air pollution. There are an estimated 376,000 livestock operations in the United States. Over 9 million US dairy cows generate about 249 million tons of wet manure annually. We monitored emissions of carbon dioxide (CO₂), methane (CH₄), and ammonia (NH₃) from fresh dairy feces and manure (mixture of feces and urine) for two weeks at a time in a research greenhouse. A closed-dynamic chamber system  coupled with a portable Fourier Transformed Infrared (FTIR) analyzer  was employed for continuous measurements of gas concentrations and fluxes. Water content and temperature were monitored with an electromagnetic capacitance sensor. Changes of pH, dry matter content, dissolved organic carbon, total carbon (TC), total ammoniacal nitrogen (TAN), and nitrate/nitric nitrogen were monitored through periodic lab testing. Emission potentials (EP) and cumulative emissions (CE) for each gas from feces and manure sources were estimated. The differences in physicochemical properties between feces and manure will be illustrated and their implications on gas emissions will be discussed.