Methane Emission from Paddy Fields and its Mitigation Options on a Field Scale

Abstract

Rice is one of the most important cereals, especially in Asian countries. Methane (CH4), one of the major greenhouse gases, is emitted from flooded paddy fields as a result of phenomena on various scales. This paper review studies on CH4 emission from paddy fields, paying special attention to mitigation options from the viewpoint of their feasibility on a field scale. Field management of rice paddies is primarily carried out to obtain suitable rice yields, but it also has physical, chemical, and biological effects on CH4 emission. Therefore, some management practices can be win-win options that sustain rice yield and mitigate CH4 emission. For example, appropriate water management for rice growth and yield is also effective in decreasing CH4 emission. Other practices, such as nitrogen fertilizer application and organic matter application can also have positive effects on rice yield and CH4 emission. Recent microbial studies have been revealing the ecology of methanogens and methanotrophs in paddy soils. Further studies on a microbial scale will offer additional clues to the mitigation of CH4 emission from paddy fields.