稻田温室气体减排成本收益分析

Cost-benefit assessment for greenhouse gas mitigation in rice-based agriculture

应用政府间气候变化专门委员会（intergovernmental panel on climate change,IPCC）推荐方法计算稻田不同技术组合温室气体排放量和单项技术减排潜力,运用边际减排成本曲线确定区域内由基准模式向最（次）优减排模式转化的相应成本,对稻田温室气体减排不同技术组合的成本-收益进行评估,确定成本有效性减排技术组合和区域内不同减排技术组合转化的边际减排成本。研究表明：（1）稻田土壤是最大排放源,其次是氮肥直接和间接排放。优化灌溉技术、氮素来源、轮作方式以及开展秸秆还田可降低水稻种植周期温室气体排放1.52%～40.17%,最大减排潜力来自于灌溉技术与模式选择差异;（2）以浙江省台州市黄岩区为例,以＂淹水灌溉＋化肥＋秸秆燃烧＂作为基准技术组合,由基准技术组合模式转向4种＂低排放＂技术组合模式的影子价格为1.63～9.79元·kg^-1CO2当量,＂淹水灌溉＋化肥＋秸秆移走（作建筑材料）＂技术组合模式最具成本有效性。

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^-1CO2equivalent（ 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.