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ARS Home » Southeast Area » Jonesboro, Arkansas » Delta Water Management Research » Research » Publications at this Location » Publication #393470
Research Project: Preserving Water Availability and Quality for Agriculture in the Lower Mississippi River Basin

Location: Delta Water Management Research

Title: Multiyear methane and nitrous oxide emissions in different irrigation management under long-term continuous rice rotation in Arkansas

Author
item KARKI, S. - University Of Arkansas
item Adviento-Borbe, Arlene
item RUNKLE, B.R.K. - University Of Arkansas
item MORENO-GARCIA, B. - University Of Arkansas
item ANDERS, M. - Net-Profit Crop Consultancy
item Reba, Michele

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2022
Publication Date: 3/22/2023
Citation: Karki, S., Adviento-Borbe, A.A., Runkle, B., Moreno-Garcia, B., Anders, M., Reba, M.L. 2023. Multiyear methane and nitrous oxide emissions in different irrigation management under long-term continuous rice rotation in Arkansas. Journal of Environmental Quality. 52(3):558-572. Available: https://doi.org/10.1002/jeq2.20444.
DOI: https://doi.org/10.1002/jeq2.20444

Interpretive Summary: Flooded rice cultivation accounts for 7-11% of total anthropogenic CH4 and N2O emissions globally. Better understanding of major drivers of gas efflux and estimates of emissions based on field measurements are needed to develop effective mitigation options for rice. A 5-year field study on commercial farm was conducted to assess influence of rice rotation and intermittent irrigation (Alternate wetting & Drying: AWD) on CH4 and N2O emissions and grain yield. Closed vented chamber technique was used to measure fluxes of CH4 and N2O. Our findings show a 66% reduction of CH4 emissions and minimal N2O emissions without significant crop yield penalty when fields were shifted from flooded to AWD practice. The study also showed apparent seasonal variation in CH4 emissions caused by weather and irrigation within the same commercial farm. Results from this study can be used by researchers, extension workers, and farmers in predicting accurate estimates of GHG emission factor and improve GHG model validation.

Technical Abstract: Flooded rice paddies are one of the major sources of anthropogenic methane (CH4) emissions. The alternate wetting and drying (AWD) irrigation management has been shown to reduce CH4 emissions and total global warming potential (GWP) in experimental field studies in the US. However, there is limited information about utilizing AWD management to reduce greenhouse gas (GHG) emissions from commercial-scale continuous rice production fields. This study was conducted for five subsequent growing seasons (2015-2019) on a pair of adjacent fields in a commercial farm in Arkansas (USA) under long-term continuous rice rotation irrigated with either continuously flooded (CF) or AWD conditions. The cumulative CH4 emissions in the growing season across the two fields and five years were in the range of 41-123 CH4-C ha-1 for CF and 1-73 kg CH4-C ha-1 for AWD. On average, AWD reduced CH4 emissions by 66% relative to CH4 emissions in CF fields. Compared to N2O emissions, CH4 emissions dominated the GWP with an average contribution of 91% in both irrigation treatments. There was no significant variation in grain yield (7.3-11.9 Mg ha-1) and N2O emissions (-0.02-0.51 kg N2O-N ha-1) between the irrigation treatments. The yield-scaled GWP was 368 and 173 kg CO2 eq. Mg-1 for CF and AWD, respectively, showing the feasibility of AWD on a commercial farm to reduce the total GHG emissions without altering the grain yield. The variations of seasonal GHG emissions observed on the same fields showed total GHG emissions were predominantly influenced by irrigation management and climate-related factors. These findings highlight the importance of long-term GHG emission studies for field validation of GHG models and emissions factors.