農(nóng)業(yè)土壤中的碳匯

Lecture9.CarbonSequestrationinAgriculturalSoils1.Theroleofsoilcarbonsequestration

2.SoilCsequestrationprocess

3.Soilcarbonsequestration

strategiesandmanagementpractices

4.Methodsofincreasingsoilcarbonsequestration

5.CarbonsequestrationpotentialinUSTheroleofsoilsequestrationinreducingGHGemissions

1).Soilcarbonisamajorglobalcarbonpool

Globalestimatesofsoilorganiccarbon(SOC)pool 0-1m(Pg) 0-2m(Pg) 0-3m(Pg)JobbagyandJackson(2000) 1502 1993 2344(Source:JobbagyandJackson(2000),Ecol.App.10:423-436)

Globalestimatesofsoilinorganiccarbon(SIC)poolReference SICpool(Pg)Batjes(1996)

695-748Eswaranetal.(2000)

940Schlesinger(1982) 780-9302)Directlinkbetweensoilandtheatmosphericcarbonpool-cultivationofvirginsoilsorconversionofnaturaltoagriculturalecosystemsleadstodepletionofSOCwiththeemissionofGHGs(CO2andCH4)e.g.thereductioninSOCpoolby1PgisequivalenttoanatmosphericenrichmentofCO2by0.47ppm3).MisuseagriculturalsoilscanbeamajorsourcesofGHGse.g.From1850to1998,globalCO2emissionsareestimatedtohavebeen:fromlandusechange: 136±55Pgfromsoilcultivations: 78±17Pg

Duringthe1990s,about25%ofglobalGHGsemissionscamefromland-usechangeandsoilcultivation(IPCC,1996)TheCCycleinAgriculturalEcosystemsCroppedsoilshavebeenhistoricallydepletedinSOC,whichcanberegainedwithimprovedmanagementCSequestrationandManagementErosionManage.WaterManage.NutrientManage.ConservationManage.EcosystemrestorationWintercovercropsRestorationoferodedsoilsAdoptionofrecommendedmanagementpracticesIdentificationandimplementationofappropriatepoliciesStrategiesforenhancingCsequestrationandreducingGHGemissionsinAgriculturalSoilsPastAgriculturalPractices:-Erosion-Intensivetillage-Residueremoval-LowproductivityImprovedAgriculturalPractices:-Conservationbuffers-Conservationtillage-Covercrops-ImprovedrotationCRPNo-till:

excludesfull-widthprimary,secondary,andsubsurfacetillage.

Sundancesystemforincorporationonsemi-permanentbedsShallowMT:

referstooperatesuchasSundanceSystemthatusesdisksandlisterbottomtoincorporatecropresiduesandcultivatethetopsandsidesofthebedsinasinglepass.DeepMT:

isintendedtoreducesoilcompaction.CRP(ConservationReserveProgram):LandseligibleforinclusionwithCRPwerethosewithannualerosionrateof42.8MT/ha(19.1tons/acre),whichis3timesthenationalaverageratesoilerosion.About24%ofalluscroplandiseligibleforinclusioninCRP(currently14.75Mha)Objective:

toconverthighlyerodiblelandfromactivecropproductiontoPermanentvegetationcoverfora10-yearperiod.SoilOrganicMatterCaseStudy:SouthDakotaCarbonSequestrationProjectBadlandsCusterStateParkSturgisRallyBlackHillsForestsMtRushmoreC-LockprojectgoalsTodevelopaninternet-basedregistrationsystemthatlinkstoaGeographicInformationSystem(GIS)coupledtosoilcarbonmodelstoestimatecarbonsequestrationforagriculturalandforestlandsToquantifyandcertifyCarbonEmissionReductionCredits(CERC)thatcanbegeneratedandsoldbyindividualproducersinSouthDakota.TheSouthDakotaCarbonSequestrationProject

HOMEPAGEContact:CarbonSequestration

/clock?-1994-2001-SDSM&T-AllRightsReserved.vC-LockProjectStrategyDeterminecarboncycledriversDevelopageographically-referenceddatabaseEstablishlinksamongobservationsandmodelsTestmodelsatendpointLANDUSESOILPROPERTIESSOILCARBONCROPCLIMATECentury4.0FarmersTillageAffectsonSOCIntensiveTillageincreasessoiltemperaturecausinghigherrateofdecompositionresultinginreductionofSOCConservationTillageretainscropresiduesloweringsoiltemperatureandprotectionfromerosion.SpinkCounty(SD)CENTURY4.0modelrun–Soilcarbon(kgC/acre)CRP(nograzing)NoTillMinimumTillageStatusQuo(Con.Tillage)(Con.Tillage)(Con.Tillage)ManagementPracticesWheat(SpinkCounty:Climatezone7––Sandyloamsoil)Corn“CashforCarbon:TheSoilBankinSouthDakota”TotalforSD:$157million(assum