Plant Physiological Performances, Plant Growth, Grain Yield and Methane Emission of Rice (Oryza Sativa L.) in Response to Water Management as Adaptation Strategy for Climate Change

Continuously flooded rice systems are a major contributor to the greenhouse gases (GHG) emissions in the agriculture sector in Malaysia. Intermittent irrigation has been recommended to replace conventional rice water management to save water and reduce GHG emissions without compromising rice yields. This study was conducted in two growing seasons at Malaysia’s largest rice granary area to determine the effectiveness of different water management practices on conserving water, mitigating GHG and maintaining rice grain yields. Three water management treatments were continuous flooding (CF), saturated and wet conditions from transplanting to heading and flooding until maturity (S-F) and continuous saturated and wet conditions (CS). The results showed that S-F and CS reduced water inputs between 15.0-16.8% and 32.0-34.0% as compared to CF, respectively. Water-saving treatments mostly did not significantly affect the plant's physiological performance, plant growth parameters, growth rate, grain yield and yield parameters. The results indicated that soil saturated and wet conditions provided adequate soil moisture content for the plant’s requirement similar to flooding conditions. Maintaining soil at saturated and wet conditions during the vegetative stage reduced 24.18-39.76% of methane emissions. However, maintaining soil at saturated and wet conditions throughout the growing season reduced 34.52-55.08% of methane emissions. In conclusion, intermittent irrigation could be an effective adaptation technique for simultaneously saving water and mitigating GHG while maintaining high rice grain yields in rice cultivation systems.