METHANE EMISSIONS FROM CHINA PADDYLAND

China has the world's largest area of rice paddy. As such, emissions of methane (CH4) from China are of interest in understanding the global CH4 budget. Using a simplified process-based methane emission model and a georeferenced database, CH4 emission rates from 329 defined agricultural zones in China, where rice production occurred, were estimated in this study. The calculated daily CH4 emission rates ranged from 0.12 g m(-2) to 0.70 g m(-2) with an average value of 0.44 g m(-2). The annual CH4 emissions varied between 25 g m(-2) and 80 g m(-2). On average across the whole rice growing area in China, 59.9 g m(-2) CH4 was released annually. Total CH4 emission was 16.2 Tg year(-1) (1 Tg = 10(12) g). Although the model and supporting database used had some uncertainties, these results demonstrated the ability to assess CH4 emissions at the regional level within the framework of climate-plant-soil interactions.