Impact of Subsurface Applying Poultry Litter On Greenhouse Gas Emissions in a Permanent Pasture.

The potential threat of global warming has caused policy makers to consider regulations to reduce greenhouse gas emissions. It is believed that agriculture could potentially offset the global warming potential of other anthropogenic sources through C sequestration. In the Southeastern US, poultry litter, which is a highly carbonaceous material, has historically been land-applied to pastures as a fertilizer source. If applied properly, poultry litter application would supply the soil with plant nutrients as well as potentially offset global warming through C sequestration. However, land application practices of poultry litter need to be evaluated to determine their effects on greenhouse gas emissions.  This study evaluated the impact of a new technology used to subsurface apply poultry litter. Treatments consisted of poultry litter (subsurface banded vs. surface application), commercial fertilizer, and a control.  Poultry litter was applied to soil at a rate of 9 Mg ha^-1 to each plot. These treatments were evaluated in two drastically different soil types (Piedmont, Coastal Plain) for a duration of four weeks in a permanent pasture system. On each sampling day, measurements of CO_2, CH₄, N₂O, and NH₄ were evaluated to assess the effects of the different practices. The information acquired from this study will aid in predicting the impact that these poultry litter application practice have on greenhouse gas emissions.