METHANE EMISSION FROM FLOODED RICE FIELDS UNDER IRRIGATED CONDITIONS

In a study on CH4 emission from flooded rice fields under irrigated co nditions, 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(-1) m(-2). During the re productive stage of the rice plants, CH4 emission was high and the oxi dation power of rice roots, in terms of alpha-naphthylamine oxidation, was very low. The CH4 emission reached a maximum at midday and declin ed to minimum levels at midnight, irrespective of the rice variety. Th e peak CH4 emission at midday was associated with higher solar radiati on and higher soil/water temperature.