Fields under corn rape rotation,soybean-winter wheat rotation,and fallow in Guizhou were selected as representative sub tropical upland soils for studying seasonal variations in N₂O flux and temperature synchronously.Furthermore,DNDC model was used to assess potential effect of the variation in air temperature in future on N₂O emissions from the fields.The results indicated that temperature was the key factor controling the diurnal regular variation in N₂O flux.Apart from that from the soybean field,N₂O fluxes from the crop fields and fallow land were positively related with the temperature,and N₂O fluxes from the fallow land in spring and winter were in exponential function with the temperature.DNDC modeling results showed,except from soybean field,N₂O fluxes from all the fields would increase with annual average temperature.The effect of temperature on N₂O fluxes would be greater in spring and winter than in summer and autumn,and from the fallow land than from the others in spring and autumn.