Methane emission from flooded rice fields under irrigated conditions

In a study on CH₄ emission from flooded rice fields under irrigated conditions, fields planted with rice emitted more methane than unplanted fields. The CH₄ efflux in planted plots varied with the rice variety and growth stage and ranged from 4 to 26 mg h^-1m^-2. During the reproductive stage of the rice plants, CH₄ emission was high and the oxidation power of rice roots, in terms of -naphthylamine oxidation, was very low. The CH₄ emission reached a maximum at midday and declined to minimum levels at midnight, irrespective of the rice variety. The peak CH₄ emission at midday was associated with higher solar radiation and higher soil/water temperature.