Greenhouse Gas Mitigation Potential of Alternate Wetting and Drying for Rrice Production at National Scale – A Modelling Case Study for the Philippines

Scenario simulations of nationwide introduction of AWD in irrigated landscapes suggest a considerable decrease of CH4 emissions by -23%, while N2O emissions are only increased by +8%. Irrespective of field management, at national scale the radiative forcing of irrigated rice production is always dominated by CH4 (>95%). The reduction potential of GHG emissions depends on, e.g., number of crops per year, residue management, amount of applied irrigation water and sand content.

Seasonal weather conditions also play an important role, since the mitigation potential of AWD is almost double as high in dry as compared to wet seasons. Furthermore, this study demonstrates the importance of temporal continuity, considering off-season emissions and the long-term development of GHG emissions across multiple years.