METHANE (CH4 ) EMISSIONS FROM PADDY RICE AND POTENTIAL MITIGATION OPTIONS

The current study was conducted to review peer-reviewed research papers on paddy rice GHG emissions and potential mitigation measures. The objective of study is to summary i) the mechanism of CH4 production and transport from paddy rice fields ii) the effect of water management, inhibitor fertilizers and organic amendments on CH4 emissions from paddy rice fields. The results showed that 50 - 75% of total CH4 produced is being oxidized before escaping to the atmosphere. CH4 formed in flooded soils can be emitted to the atmosphere via three pathways: Diffusion (<1% of the total emission), bubbling (ebullition: 10%) and through the plant aerenchyma (90%). The drainage of paddy rice fields markedly reduced total seasonal CH4 emissions (22 - 88 %) compared to the continuously flooded treatment without reducing rice yields. The inhibitors fertilizer such as ammonium sulphate (except for acid sulphate soil), gypsum and ammonium nitrate can significantly reduce CH4 emission from paddy rice field. The application of biochar for paddy rice has shown potential to lower CH4 emissions in comparison with treatments amended with compost, and fresh manure.