EFFECT OF INTERMITTENT IRRIGATION ON METHANE EMISSION FROM AN INDONESIAN PADDY FIELD

Effect of intermittent irrigation on CH4 emission from an Indonesian p addy field with plots subjected to the application of various types of fertilizer was studied. Intermittent irrigation treatment was conduct ed once a week from immediately before heading time to harvest time. T he mean CH4 emission rates (mg CH4 m(-2) h(-1)) during the intermitten t irrigation period were in the ranges of 26.6-29.0 and 20.6-27.6 for the chemical fertilizer plots with continuous flooding and intermitten t irrigation, respectively. They ranged from 17.9 to 29.0 and 25.2 to 31.7 for the plots treated with both urea and organic materials. These rates were similar to those observed in the same held under continuou s flooding during the rainy season cultivation. Thus, the effects of i ntermittent irrigation were not significant in the paddy field studied . The total amount of CH4 emitted (g CH4 m(-2)) throughout the growth period was 36-45 and 29-44 for the chemical fertilizer plots with cont inuous flooding and with intermittent irrigation, respectively, while 32-50 and 43-47 from the plots amended with organic materials.