利用农业土壤固定有机碳——缓解全球变暖与提高土壤生产力

Carbon Sequestration in Farming Land Soils: an Approach to Buffer the Global Warming and to Improve Soil Productivity

大气CO2浓度急剧升高与全球气候变暖是当今最令人关心的环境问题之一。农业具有作为大气CO2源和库的双重潜力。鉴于多年的少耕、免耕和合理轮作等农业管理措施已明显增加北美土壤有机碳含量，美国和加拿大两国土壤学家认为这里的土壤已从大气CO2的供体转变为固定大气CO2的库。美加两国将在今后20 a内增加土壤有机碳储量11亿t，这相当于两国在京都全球气候变化大会承诺到2008至2012年减少CO2排放量的15%。因此，北美土壤学家和政府有关部门正积极争取将土壤固碳纳入全球温室效应气体控制公约的国际谈判桌上。中国土壤固碳潜力较美加两国要大，采用少耕、免耕、作物桔杆还田及引进覆盖作物等农艺措施不仅将恢复中国退化中的土壤肥力，也将在未来的温室效应气体控制谈判中保护中国发展中的工业。

Global warming associated with arising of atmospheric CO2 is one the most challenging issues today. Agricultural soils behave either a source or a sink of the atmospheric CO2. Based upon the results of soil organic carbon increasing under conservation management, such as reduced- and no-till practice, rotation, and introducing cover crops in many long-term experimental in North America, soil scientists in USA and Canada believe that arable lands here have been changing from the source to the sink of atmospheric CO2. They further believe that carbon sequestrated in North America soils during next 20 years can reach 1.1 billion tons, accounting for 15% of total commission (in year 2008 ~ 2012) of both countries for CO2 emission reduction in the Kyoto Protocol. Hence, soil scientists and related governmental organizations are struggling to introduce the concept of carbon sequestration in soils to the negotiating table of global warming debate. The potential of soil sequestrating carbon is bigger in China than in North America. Management practices, such as conservation tillage, rotation, and cover cropping, widely adopted in North America would not only benefit our degrading soils, but also strengthen China's position in the future global warming negotiation.