中文摘要：

农田土壤碳库对缓解气候变化、保证粮食安全具有重要作用。日益加剧的气候变化对农田土壤有机碳库演变的潜在影响受到广泛关注。全球气候变化所带来的温度、降雨和大气二氧化碳（CO2）浓度的改变,会通过影响净初级生产力（NPP）、外源碳投入和有机碳分解速率等因素改变生态系统碳循环过程。另外,气候变化也会通过改变土地利用方式和种植制度等农业措施改变生态系统碳循环。综述国内外农田土壤碳库演变对气候变化影响的研究成果表明,到21世纪末,中国气温将会升高3.9—6.0℃,降水有望增加9%—11%。至2050年,气温和降水的变化会造成中国农田系统碳投入相比1980年降低2.3%—10%（小麦、玉米和水稻平均值）。相反,在综合考虑CO2浓度升高的协同作用后,2050年中国农田系统碳投入相比1990年前将会增加13%—22%（平均年增长率0.2%—0.4%）。模型预测显示,至2020、2050和2080年,中国旱地0—30 cm土层有机碳在CO2低排放情景下分别会损失2.7、6.0和7.8 tC.hm-2,在CO2高排放情景下分别会损失2.9、6.8和8.2 tC.hm-2,大概占1980年农田土壤碳的4.5%、10.5%和12.7%。综合碳投入和排放对农田土壤碳库的整体影响来看,21世纪末期中国农田土壤有机碳库含量较1980年会下降10%左右,但如果采取相应的管理措施,可有效抑制农田土壤碳库的降低甚至提高,如农田系统碳投入以每年1%的速度增加时,土壤碳库会在21世纪末增加两倍。目前的研究结果显示,气候变化是否会强烈影响农田土壤碳库依然有很大的不确定因素,其对固碳效应正面和负面影响相互抵消后成为碳源还是碳汇说法不一。因此,在采取缓解气候变化、增加农田土壤固碳的措施的同时,还需加强农田土壤碳库未来变化趋势的研究和探索,为中国政策框架的决定以及未来气候变化谈判提供可靠的科学依据。

英文摘要：

Soil organic carbon（SOC） in agricultural soils plays an important role for ensuring food security and mitigating global climate change. Thus, the past and potential effects of climate change on the SOC in agricultural soils have been widely noticed by global society. The net primary productivity（NPP）, carbon input and SOC decomposition rate could be altered by changes of temperature, precipitation and CO2 concentration due to the global climate change. Furthermore, carbon cycling could also be changed by the changes of land use and planting systems under climate change. The published data were used to illustrate the effects of global climate change on SOC in upland in China. It is estimated that the increase of temperature and precipitation ranged from3.9 to 6.0 ℃ and from 9% to 11% in China until 2050 s, respectively, and carbon input in agricultural system will be decreased by2.3%-10%（average of wheat, maize and rice cropping systems）. However, if consider the combined effects of increase of CO2 concentration with global warming, carbon input will be increased by 13%-22% until 2050 s compared with that before the period of1990 s. Model simulation results showed that until 2020 s, 2050 s and 2080 s, SOC will be decreased by 2.7, 6.0 and 7.8 t C·hm-2 under CO2 emission scenario, and be decreased by 2.9, 6.8 and 8.2 t C·hm-2 under high CO2 emission scenario, respectively, which is ca.4.5%, 10.5% and 12.7% of the SOC pool in 1980 s. Furthermore, SOC pool will be decreased approximately by 10% at the end of the21 st century. If C inputs in agricultural systems are promoted with a 1% annual increase rate, there is a 100% increase in carbon input in agricultural soils by the end of the 21 st century in China. An obvious uncertainty still remain whether the climate change will exert huge influence on soil carbon pool. The consensus that the positive and negative of soil carbon sequestration counteract to become carbon sink or source has not been reached. Thus, in the meanwhile of mitigating climate chan