Abstract
Effects of intermittent irrigation with different intervals on greenhouse gas emissions and rice yield were investigated in rice paddy fields. Three treatments for water management practices were prepared as: (1) continuous flooding except during the midseason drainage, (2) intermittent irrigation with two-day drainage, and (3) intermittent irrigation with four-day drainage. The longer the drainage period in intermittent irrigation, the less the CH4 was emitted whereas the more the N2O was. Two-day drainage treatment had the smallest cumulative CO2-equivalent fluxes for CH4 and N2O. Decreases in a drainage period resulted in the reduction of the net greenhouse gas emission. Brown rice yields were the highest for the continuous flooding treatment. The yields of two-day and four-day drainage treatments were smaller than that of the continuous flooding treatment by 13% and 18%, respectively. The two-day drainage treatment achieved the smallest net greenhouse gas emission per brown rice yield, thus mitigated the emission of CH4 and N2O with maintaining yield.
