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1、SoilCarbonSequestrationImpactsonGlobalClimateChangeandFoodSecurityTutor:Prof.ZHENGSpeaker:DongXiaogangDate:2012-05-10R.Lal,etal.2004Science304,1623土壤碳固定对全球气候变化和粮食安全的影响2.SoilCarbonSequestration3.SoilCarbonSequestrationforMitigatingClimateChange4.SoilCa
2、rbonSequestrationandGlobalFoodSecurity5.Conclusions1.BackgroundContentTheglobalsoilcarbon(C)poolof2500gigatons(Gt)includesabout1550Gtofsoilorganiccarbon(SOC)and950Gtofsoilinorganiccarbon(SIC).1.BackgroundThesoilCpoolis3.3timesthesizeoftheatmosphericpo
3、ol(760Gt)and4.5timesthesizeofthebioticpool(560Gt,fig.S1).25000亿吨的全球土壤碳库由15500亿吨的土壤有机碳和9500亿吨的土壤无机碳组成。土壤碳库的容量是大气碳库的3.3倍，是生物碳库的4.5倍。Fig.1.Processesaffectingsoilorganiccarbon(SOC)dynamics.TheSOCpoolrepresentsadynamicequilibriumofgainsandlosses(Fig.1).土壤碳
4、库处于收支动态平衡。SeveredepletionoftheSOCpooldegradessoilquality,reducesbiomassproductivity,andadverselyimpactswaterquality,andthedepletionmaybeexacerbatedbyprojectedglobalwarming.ThedepletionisexacerbatedwhentheoutputofCexceedstheinputandwhensoildegradationi
5、ssevere.当输出超过输入和土壤退化严重时土壤碳库的耗竭将加剧。土壤碳库的严重耗竭使得土壤质量退化，生物产量降低，影响水质量，预测的全球变暖可能会加剧土壤碳库的耗竭。TheestimatesofhistoricSOClossrangewidely,from44to537Gt,withacommonrangeof55to78Gt(3).以往的土壤有机碳的损失量的估算值变化范围广大约从440到5370亿吨，而共识的损失量是550到780亿吨。2.SoilCarbonSequestrationCar
6、bonsequestrationimpliestransferringatmosphericCO2intolong-livedpoolsandstoringitsecurelysoitisnotimmediatelyreemitted.Thus,soilCsequestrationmeansincreasingSOCandSICstocksthroughjudiciouslanduseandrecommendedmanagementpractices(RMPs).土壤碳固定意味着将大气中的CO2转
7、移到长期存在的土壤库中并安全地储存它，因此使碳不能立即释放到大气中。因此土壤碳固定意味着通过精确的土地使用和推荐的管理措施(RMPs)增加了土壤有机和无机碳库的容量。TheSOCsequestrationiscausedbythosemanagementsystemsthataddhighamountsofbiomasstothesoil,causeminimalsoildisturbance,conservesoilandwater,improvesoilstructure,enhanceact
8、ivityandspeciesdiversityofsoilfauna,andstrengthenmechanismsofelementalcycling(Fig.2,tableS2).土壤有机碳的固定是由向土壤中增加高生物量，使土壤受到最小的扰动，保持水土，提高土壤结构，增强土壤动物的种类和多样性的活性，增强元素循环而实现的。(Fig.2,tableS2)2.SoilCarbonSequestrationFig.2.具有高的土壤碳固定潜能的态系统有:农田，放牧的草地，退化的或沙漠
