A study explores how water management practices influence the greenhouse gas emissions-related environmental impacts of rice cultivation. An estimated 2.5% of human-induced climate warming has been attributed to methane release from rice cultivation worldwide. However, the estimates do not account for emissions of nitrous oxide (N2O), a long-lived greenhouse gas tied to the practice of intermittent flooding used in rice cultivation. To examine the impact of alternative water management practices aimed at reducing methane emissions from rice farms, Kritee Kritee and colleagues monitored five rice fields across three agroecological regions in India between 2012 and 2014. The authors found that N2O emissions per hectare was up to three times higher in intermittently flooded fields than previous reports, and the authors estimate that increased use of intermittent flooding in the Indian subcontinent might result in N2O emissions 30-45 times higher than under continuous flooding. The authors suggest that co-management of water, nitrogen, and carbon can decrease net climate impacts due to methane and nitrous oxide emissions by 10-90%, compared with baseline practices. The findings highlight the need for global assessments of N2O emissions from rice and carry policy implications for climate-friendly rice production, according to the authors.
Article #18-09276: "High nitrous oxide fluxes from rice indicate the need to manage water for both long- and short-term climate impacts," by Kritee Kritee et al.
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Proceedings of the National Academy of Sciences