The following parameters; CH4 release (gas emissions),temperature, and oxidation reduction potential (Eh) were mea-sured every 2 days, while the PNSB population was monitored every 5 days for all plots. The CH4 release and soil Eh at a depth of 5 cm were measured at approximately the same time of day. In this study, the most probable number (MPN) technique was used to count PNSB from the soil surface by following the method described by Harada et al. (2001a). CH4 emission rates (flux) were measured by using a gas trap consisting of a cylindrical acrylic chamber (L W H: 13 13 100 cm and 0.3 cm thickness) equipped with a battery-powered fan. Gas samples were taken at 60 and 120 min after the cylindrical chambers were connected to each plot. The gas sample was drawn from the chamber with a 50-mL plastic syringe at the top of the chamber and injected into a