Effect of Irrigation Water Management Practices and Rice Cultivars on Methane (CH^sub 4^) Emission and Rice Productivity

An experiment was conducted to investigate the effect of irrigation water management practices and rice cultivars (BRRI Dhan-28 and BINA Dhan-8) on methane (CH^sub 4^) emission and rice productivity during Boro season at the experimental field of Department of Environmental Science, Bangladesh Agricultural University, Mymensingh. Different water management practices such as Continuous flooding (CF) at 5 cm standing water, CF at 5cm standing water for first 3 weeks, CF at 5cm standing water for first 6 weeks, CF at 5cm standing water for first 9 weeks, alternate wetting and drying and water saturated condition were followed in the different plot in this experiment. It was observed that alternate wetting and drying treatment gave highest yield 5.76 t/ha and 6.713 t/ha respectively in BRRI Dhan-28 and BINA Dhan-8. However, the lowest seasonal methane emission 13.349 g CH^sub 4^/m^sup 2^/season and 13.808 g CH^sub 4^/m^sup 2^/season were found under the alternate wetting and drying in BRRI Dhan-28 and BINA Dhan-8 respectively.