Greenhouse gas emissions in tailwater-reuse row rice
Abstract
As part of the USDA-NRCS project "How low can you go? Automating tailwater reuse in rice," the lab quantifies greenhouse-gas emissions and global warming potential in continuously flooded versus end-blocked, tailwater-recirculating furrow-irrigated rice.
Period of Performance
2023 - 2027
Funding Agency
USDA-NRCS
Methods
Using static flux chambers and six eddy covariance towers across paired farm sites near Belzoni and Isola, the team measures methane, nitrous oxide, and carbon dioxide, relating emissions to grain yield and irrigation practice and feeding a rice sub-model for USDA COMET-Farm.
Results
Key findings Recirculating tailwater in furrow-irrigated rice reduced methane (CH₄) emissions — without a yield penalty. Seasonal CH₄ was ~76% lower in the furrow-irrigated upper position than in continuously flooded rice, while the lower position ran higher: position within the field matters. Productivity—emission tradeoffs can leave yield-scaled emissions comparable across irrigation systems. One season of static-chamber data (2024) is complete; six flux towers now measure CH₄ and evapotranspiration, with off-season processing producing seasonal CH₄ and ET budgets.