Greenhouse gas (GHG) emissions and high-water requirements in transplanted rice are critical issues contributing to climate change and the depletion of freshwater reserves. The adoption of water-saving irrigation practices and improved rice cultivars is important for mitigating GHG emissions and addressing water scarcity while maintaining high crop yields. The objective of this study was to investigate the impact of the duration of the rice cultivar and intermittent irrigation scheduling on water productivity, rice yield, net GHG emissions, and greenhouse gas intensity (GHGI). The field experiment was conducted with two rice cultivars (long-duration and short-duration) and three irrigation regimes (continuous flooding, CF; irrigation two days after infiltration of ponded water, 2DAIPW; irrigation three days after infiltration of ponded water, 3DAIPW) during 2019 and 2020. The results revealed that regardless of irrigation regime, the short-duration cultivar saved irrigation water (17%), reduced CH (12%), NO (11%) and net GHG emissions (12%), and had lower grain yield relative to long-duration cultivar. The actual crop water productivity (ACWP), total crop water productivity (TCWP), and greenhouse gas intensity (GHGI) were comparable for both the cultivars. Irrespective of cultivars, the 2DAIPW regime saved 21% of the irrigation water, led to the emission of 24% less CH and 49% higher NO compared to CF. However, the 3DAIPW regime saved 31% of irrigation water, decreased CH emissions by 39% and increased NO emissions by 29%, respectively, over the CF regime. Practicing the 3DAIPW irrigation regime over CF significantly increased ACWP (41%) and TCWP (26%) and reduced net GHG emissions (28%) and GHGI (26%). These findings suggest that the cultivation of short-duration rice cultivar and the 3DAIPW irrigation regime have the potential to mitigate GHG emissions and saving of irrigation water.

中文翻译：

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稻田甲烷和一氧化二氮排放量受栽培品种持续时间和灌溉制度的影响

移栽水稻的温室气体（GHG）排放和高需水量是导致气候变化和淡水储备枯竭的关键问题。采用节水灌溉措施和改良水稻品种对于减少温室气体排放和解决水资源短缺问题同时保持作物高产非常重要。本研究的目的是调查水稻品种的持续时间和间歇性灌溉计划对水生产率、水稻产量、温室气体净排放量和温室气体强度（GHGI）的影响。田间试验采用两种水稻品种（长持续时间和短持续时间）和三种灌溉方式（连续淹没，CF；积水入渗两天后灌溉，2DAIPW；积水入渗三天后灌溉，3DAIPW） 2019 年和 2020 年期间。结果显示，无论灌溉方式如何，短期品种都节省了灌溉水 (17%)，减少了 CH (12%)、NO (11%) 和温室气体净排放 (12%)，并且与长期品种相比，谷物产量较低。两个品种的实际作物水分生产率（ACWP）、作物总水分生产率（TCWP）和温室气体强度（GHGI）相当。无论品种如何，与 CF 相比，2DAIPW 方案可节省 21% 的灌溉水，CH 排放量减少 24%，NO 排放量增加 49%。然而，与 CF 制度相比，3DAIPW 制度节省了 31% 的灌溉水，减少了 39% 的 CH 排放量，增加了 29% 的 N2O 排放量。在 CF 上实施 3DAIPW 灌溉制度显着增加了 ACWP (41%) 和 TCWP (26%)，并减少了净 GHG 排放量 (28%) 和 GHGI (26%)。这些发现表明，短期水稻品种的种植和 3DAIPW 灌溉制度具有减少温室气体排放和节省灌溉水的潜力。