Abstract: This study presented a modeling tool to assess emission of greenhouse gases（GHGs）from ricebased agricultural system as affected by different mitigation technologies， as well as mitigation potential of single technology according to technical coefficients recommended by intergovernmental panel on climate change （IPCC）. As there were a range of technically feasible measures to reduce agricultural GHG emissions， the present study also developed a marginal abatement cost curve （MACC） to assess their costeffectiveness and mitigation potential in the field. It was shown that with the current farmers practice in China， soilborne emissions were the major source of GHGs， followed by nitrogen fertilizer application both onand offfarm. Through improvement in water management， inorganic/organic N supply， rotation and straw returning， GHG emission could be reduced by 1.52% to 40.17% during the whole cropping cycle. A significant reduction of global warming potential （GWP） could be achieved by modification of water management. The present study then assessed GHG emissions and economic returns under different mitigation technologies in rice growing region. Taking Huangyan District， Taizhou City as an example， the shadow price would be 1.63 to 9.79 yuan·kg-1 CO2 equivalent （CE） when baseline technology （continuous flooding， urea fertilization， burning of rice straw） was converted to preferable options， and the technology combinations including continuous flooding， urea fertilization and straw used as construction material exhibited the highest costeffectiveness.

Key words: ricebased agricultural system, greenhouse gases emissions, methane, costbenefit analysis