Comparison of Model Validation on Methane Emissions From Rice Fields in Thailand

摘要

Wetland rice soils have been shown to be an important methane source at the global scale. Recently many researchers dealed with model implementation on methane emissions in order to reduce uncertainty of emissions estimated. These models are different in term of assessment and conceptual implementations. This study focused on the application of existing process base model and empirical model in order to access the appropriate estimation on methane emissions from irrigated rice fields. Three locations namely Singburi (Ratchburi soil series), Nonthaburi (Bangkok soil series), and Kanchanaburi (Saraburi soil series) used in this experiment. These three rice fields were cultivated with local practices of crop management, consisted of continuous flooding and urea applications and without organic fertilizer applications. The process base model and empirical model were used in this study. The results shown good agreement of methane emissions between observed fields and DNDC site mode. The highest methane emission was estimated from Ratchburi soil series which highest organic carbon, while the lowest emission was estimated from Saraburi soil series which lowest organic carbon content. Whereas the regional mode shown high methane emission from high rice cultivation area. Empirical model which influenced by percentage of sand content in the soil, shown high methane emissions with high content of sand. The results from this study, process base model and empirical model, shown the possibility to be use for estimated methane emissions from irrigated rice fields.