Field evolution of CH₄ and CO₂ from soils under four dominant land uses in the Mardi watershed, western Nepal, were monitored at 15-day intervals for 1 year using closed chamber techniques. The CH₄ oxidation rate (mean plus or minus SE, micro g CH₄ m^-2 h^{- 1}) in the forest (22.8 plus or minus 6) was significantly higher than under grazing land (14 plus or minus 2) and an upland rainfed maize and millet system (Bari) (2.6 plus or minus 0.9). Irrigated rice fields (Khet) showed an oxidation rate of 6 plus or minus 0.8 micro g CH₄ m^-2 h^-1 in the dry season (December-May) but emitted a mean rate of 131 micro g CH₄ m^-2 h^-1 in the rainy season and autumn (June-October). The evolution of CO₂ ranged from 10 mg CO₂ m^-2 h^-1 in the Bari in January to 1,610 mg CO₂ m^-2 h^-1 in the forest in July. Higher evolution of CO₂ (mean plus or minus SE, mg CO₂ m^{- 2} h^-1) was observed in the Bari (399 plus or minus 39) and forest (357 plus or minus 36) compared to Khet (246 plus or minus 25) and grazing (206 plus or minus 20) lands. The annual emission of CO₂ evolution varied from 86.6 to 1,836 g CO₂ m^-2 year^-1. The activation energy for CH₄ and CO₂ varied between 16-283 and 80-117 kJ mol^-1, respectively. The estimated temperature coefficient for CO₂ emission varied from 2.5 to 5.0. Temperature explained 46-51% of the variation in CO₂ evolution, whereas it explained only 4-36% of the variation in CH₄ evolution.