A Comparison of Eddy Covariance and Static Vented Chamber Measurements of Greenhouse Gas Flux in Mid-South US Rice

Abstract:

Rice (Oryza sativa) production in the Lower Mississippi River Basin constitutes over 75% of US rice production, but little research has been done on water and greenhouse gas (GHG) flux in this region at the field scale. Measurements of these fluxes were made in 2014 from a 26.3 ha drill-seeded rice (CL XL 753) field. Eddy covariance measurements of water and carbon dioxide (CO₂) and methane (CH4) fluxes allow for an integrated field measurement of the interaction between the landscape and the atmosphere. A static vented chamber technique was also used to measure fluxes of CO₂, N₂O (nitrous oxide) and CH₄ in the same field on 19 occasions during the rice growing season. Estimates of GHG flux using static vented chamber were compared with the GHG fluxes from the eddy covariance method. These findings begin to address the increased interest in understanding agricultural impact on net GHG emission and consumption in an understudied region of the US. Future research might include similar data collection from multiple fields where water management is varied to measure its impact on net GHG flux.