Do paddy soils of Sri Lanka emit excessive amounts of methane? - a potent greenhouse gas (GHG) responsible for global warming and climate change

Paddy soils are considered as a major source of methane (CH4), which is the second most important atmospheric greenhouse gas (GHG) after the carbon dioxide. Estimation of methane flux from paddy soils in a given country mainly depends on its total extent of paddy lands. Further, a variety of other edaphic and agronomic factors such as redox potential of the soil, soil reaction, organic matter content, soil temperature, rice variety or cultivar, water management, fertilizer application, and more importantly the population sizes of methanogens, methantrophs and other competitive bacteria contributes to the CH4 flux from paddy soils. This paper proposes that estimation of methane emission from paddy soils in Sri Lanka should be region-specific as the foregoing edaphic and agronomic factors are highly spatially variable in 46 agro-ecological regions (AERs) of the country, out of which paddy is cultivated in 40 AERs.