USING AGRICULTURAL AND INDUSTRIAL BYPRODUCTS TO IMPROVE CROP PRODUCTION SYSTEMS AND ENVIRONMENTAL QUALITY
Location: National Soil Dynamics Laboratory
Title: Tillage and fertilizer management effects on soil atmospheric exchanges of methane and nitrous oxide in a corn production system
Submitted to: Applied and Environmental Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 25, 2011
Publication Date: September 29, 2011
Citation: Nyakatawa, E.Z., Mays, D.A., Way, T.R., Torbert III, H.A., Smith, D.R., Watts, D.B. 2011. Tillage and fertilizer management effects on soil atmospheric exchanges of methane and nitrous oxide in a corn production system. Applied and Environmental Soil Science. Article ID 475370, 12 pages doi:10.1155/2011/475370. Available: http://www.hindawi.com/journals/aess/ 2011/475370.
Interpretive Summary: Agricultural soil is a source of greenhouse gases such as methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2). Poultry litter is a mixture of poultry manure and a bedding material, such as pine shavings. Manure, including poultry litter, is a useful fertilizer, but has been shown to emit greenhouse gases into the atmosphere. Poultry litter is commonly spread on agricultural fields using a broadcast application method that places the litter on the soil surface. Subsurface band application is a new method for applying poultry litter in shallow trenches in the soil and covering the litter with a two-inch thick layer of soil. Corn was grown in a field experiment on a silt loam soil in north Alabama. The two types of fertilizer used were poultry litter and ammonium nitrate fertilizer, which is a conventional commercially-available fertilizer. The three methods for applying fertilizer to the soil were broadcast application on the soil surface, subsurface band application, and soil incorporation in which the fertilizer was tilled into the top few inches of soil. The two types of crop management systems used were conventional tillage, in which the soil was tilled before planting the corn, and no-till, in which a wheat cover crop was grown and the soil was not tilled before planting. Emissions of methane and nitrous oxide from the soil surface were measured. Field plots that received poultry litter using the conventional surface broadcast application method or the soil incorporation method were net emitters of nitrous oxide, whereas the plots that received poultry litter with subsurface band application were net sinks of nitrous oxide. The best poultry litter management strategy for reducing methane and nitrous oxide emissions was no-till with subsurface band application of the poultry litter.
Land application of poultry litter (PL) presents an opportunity to improve soil productivity. There is a need to develop and evaluate agronomic and soil management strategies to minimize agricultural greenhouse gas emissions, thereby making land application of manure environmentally sustainable. We investigated methane (CH4) and nitrous oxide (N2O) emissions from agricultural soil receiving PL and ammonium nitrate (AN) fertilizer, using surface broadcast application (SA), soil incorporation (SI), and subsurface band (BA) application methods in conventional (CT) and no-tillage (NT) corn cropping systems on a silt loam soil in the Tennessee Valley region of north Alabama. Plots under CT and NT were sinks of CH4 in the spring, summer, and fall. In winter, the plots had net emissions of 3.32 and 4.24 g CH4 ha-1 day-1 in CT and NT systems, respectively. Conventional tillage and grass fallow plots had cumulative N2O emission of 9.24 and 85.70 g N2O ha-1 day-1, respectively, whereas NT plots were net sinks of N2O. Plots that received AN were net emitters of CH4 and N2O, irrespective of application method, whereas plots which received PL were net sinks of CH4, irrespective of application method. Plots that received PL using SA or SI application methods were net emitters of N2O, whereas the plots that received PL with BA application were net sinks of N2O. No-tillage with BA application of PL was the best PL management strategy for reducing CH4 and N2O emissions. [GRACEnet Publication]