Tuesday, November 3, 2009
Convention Center, Exhibit Hall BC, Second Floor
Land application of poultry litter (PL) as a fertilizer in no-till (NT) conservation tillage provides an option for animal waste disposal in the southeastern U.S. However, soil and fertilizer management strategies for reducing emissions of carbon dioxide (CO2) in NT systems are required to ensure an environmentally sustainable production system. This paper discusses CO2 emissions in a soil receiving PL and ammonium nitrate (AN) fertilizers for corn (Zea mays L.) production in no-till (NT) and conventional tillage (CT) systems, using surface (SA), soil incorporation (SI), and subsurface band application (BA) methods, on a Decatur silt loam soil in north Alabama. Soil gas samples were collected using custom built static chambers and analyzed for CO2 gas concentrations for calculating soil gas fluxes. The highest Net soil CO2 flux of 22.8 mg m-2 min-1 was observed in CT plots with soil incorporation of PL (CT-PL-SI), followed by fluxes in NT with surface application of AN (NT-AN-SA), conventional till with surface application of PL (CT-PL-SA), and no-till with surface application of PL (NT-PL-SA), which had a mean net flux of 8.7 mg m-2 min-1 from April 2008 to March 2009. Net CO2 fluxes in the other treatments, which averaged 5.4 mg m-2 min-1 were similar to that from a control undisturbed grass plot. Our study shows that subsurface band application of PL in NT conservation tillage system can reduce soil CO2 emissions by up to 50% compared to surface application in both CT and NT systems, and by up to 300% compared to soil incorporation of PL in CT system.