Greenhouse gas emissions from dry direct-seeded and transplanted rice: A comparative analysis under different water regimes in farmers’ rice fields

Dry-direct-seeded rice (DSR), a potential climate-smart alternative to puddled transplanted rice, requires less water and reduces greenhouse gas (GHG) emissions; however, its effects on GHG emissions, global warming potential (GWP), and yield from in situ field measurement in Bangladesh are insufficiently documented. Multi-location and multi-year field experiments were conducted at Rajshahi and Rangpur regions in Bangladesh during two consecutive Boro (dry) and Aus (pre-monsoon) seasons to evaluate the effects of dry DSR, transplanted rice with flooded irrigation (TFI), and transplanted rice with intermittent flooding-drying irrigation (TAD) on rice yield, CH 4 and N 2 O emissions, GWP, and GHG intensity (GHGI). Across various locations and seasons, DSR and TAD decreased overall CH₄ emissions by 13–36% and 4–20%, respectively, compared to TFI. While both DSR and TAD increased N₂O emissions by 28–34% and 12–31%, respectively, compared to TFI, the contribution of N₂O to total GWP was minor, resulting in lower GWP and GHGI under DSR and TAD. Spatial variability was observed, with higher CH 4 emissions (10–30%), GWP (10–28%), and GHGI (35%) in Rajshahi than in Rangpur across establishment methods and seasons. DSR reduced yield only in Rajshahi during the Boro season, but no yield penalties were observed in Rangpur or in the Aus season. The sustainability footprint analysis and regional adoption scenarios further demonstrated that expanding DSR coverage notably reduces CH₄ emissions and GWP. Overall, dry DSR and TAD offer substantial potential to mitigate GHG emissions from farmers’ rice fields in Bangladesh; however, successful DSR adoption requires location-specific management to sustain yield.