Mitigating greenhouse gas emissions through climate-smart rice cultivars and optimized water–fertilizer management

Greenhouse gas (GHG) emissions from rice cultivation contribute substantially to climate change, underscoring the need for effective mitigation strategies. A multi-location field experiment was conducted over two consecutive Boro (dry) seasons across different agroecological zones of Bangladesh to evaluate the effects of irrigation regimes, rice cultivars, and fertilizer management on methane (CH₄) and nitrous oxide (N₂O) emissions. Gas fluxes were measured using the closed chamber technique with three replications.

The results showed that urea deep placement (UDP) significantly reduced CH₄ emissions by approximately 20% compared with farmers’ practice (FP), while integrated nutrient management increased emissions by about 13% relative to FP. Alternate wetting and drying (AWD) irrigation reduced total CH₄ emissions by 25–30% compared with continuous flooding (CF) without significant yield penalties. Although AWD increased N₂O emissions, the net effect was offset by the substantial reduction in CH₄ emissions. Among cultivars, BRRI dhan67 reduced CH₄ emissions by 10–15% compared with BRRI dhan50 and BRRI dhan92, while BRRI hybrid dhan3 reduced emissions by 6–12% relative to the same cultivars during the Boro season. The effects of cultivar on N₂O emissions were not significant. BRRI hybrid dhan3 produced 10–15% higher grain yield than the other cultivars. In addition, UDP significantly increased rice yield and nitrogen use efficiency compared with broadcast application of prilled urea.

The results provide a strong scientific basis for policymakers to promote these technologies nationwide to mitigate climate change impacts and support sustainable food security for a growing population.