Effects of Specific Integrated Practices On Greenhouse Gas Fluxes From Bioenergy Sorghum Production In Central Texas.

Renewed interest in biofuel production has been enhanced by goals to reduce dependence on foreign energy and to potentially mitigate greenhouse gas (GHG) emissions. Most biofuel cropping systems utilize nitrogen (N) fertilizers to attain crop yield goals. Nitrogen fertilization, however, may increase the potential for higher N₂O fluxes. Furthermore, additional GHGs, such as CO₂ and CH₄, may be released from the soil surface at a higher rate which potentially negates some GHG mitigation goals sought by large-scale production of biofuels. Various biofuel crop production management practices such as fertilization, residue removal, and crop rotation may have interactive effects on GHG fluxes from the soil. Since June of 2010, field measurements of GHG fluxes have been collected with a photoacoustic infrared gas analyzer from a bioenergy sorghum cropping system near College Station, Texas. Within this cropping system, various treatments of N fertilization rate, residue return, and crop rotation have been examined. The objective of this research is to determine impacts of crop rotation, N fertilization, and residue management on GHG (CO₂, CH₄, N₂O) emissions from bioenergy sorghum production in central Texas. Results from the first two growing seasons will be discussed as well as data from the first fallow season. The goal of this research is to identify an ideal combination of N fertilization rate, residue return, and crop rotation to reduce GHG emissions while maintaining optimal crop production.