Denitrification and N2O Emissions From Carolina Bays Receiving Poultry Runoff.

On the southeastern Coastal Plain, there are depressional wetlands known as Carolina Bays that may receive runoff from agricultural land. Little is known about denitrification and gas emission within these isolated wetlands. Three forested Carolina Bays were selected to observe denitrification enzyme assay (DEA) and N2O emissions. Each bay was adjacent to farmland receiving poultry manure applications. The upper 6 inches of the soil were sampled across a four point transect within each of the Bays. Gas emissions were measured in the field using a photoacoustic analyzer. The DEA was measured in the lab using the acetylene inhibition method. Emissions of N2O averaged 3.26 mg m-2 d-1 in the bays in the spring but dropped below photoacoustic detection in the summer and fall. An adjacent soybean field had an N2O flux of 8.01 mg m-2 d-1 during the summer months following poultry application. Nitrogen runoff into these depressional wetlands appears to have minimal impact on the measured N2O flux.