SoilandItsUses土壤及其利用課件

SoilandItsUsesSoilandItsUses1Outline:SoilFormationSoilPropertiesErosionSoilConservationOutline:SoilFormation2Land-Portionoftheworldnotcoveredbywater.Soil-Mixtureofminerals,organicmaterial,livingorganisms,air,andwater.Land-Portionoftheworldno3SoilFormationSoilformationbeginswithfragmentationofparentmaterial.母巖-Ancientrocklayerswithrecentdepositsfromlavaorglacialflows.

熔巖或冰河流動(dòng)Weathering

風(fēng)化-Factorsbringingaboutfragmentation破碎orchemicalchangeofparentmaterial.SoilFormationSoilformationb4MechanicalWeathering

物理風(fēng)化,原生礦物Resultsfromphysicalforcesreducingsizeofrockparticleswithoutchangingthechemicalnatureoftherock.FreezingandThawingCyclesErosionfromWindandMovingWaterMechanicalWeathering物理風(fēng)化,原生5ChemicalWeathering

化學(xué)風(fēng)化，次生礦物-Involvesthechemicalalterationofrockinsuchamannerthatitismorelikelytofragmentorbedissolved.Rockfragmentsexposedtoatmospheremayoxidize,orotherwisechemicallychange.ChemicalWeathering化學(xué)風(fēng)化，次生礦物6Humus-Decayingorganicmaterial.mixedwiththetoplayersofrockparticles,andsuppliessomeoftheneedednutrientstoplants.Increasethewater-holdingcapacityandinorganicnutrientsolubility(acidcond.)createscrumblysoilwhichallowsadequatewaterabsorptionanddrainage.Humus-Decayingorganicmater7Otherfactorsinfluencingsoilformation:Burrowinganimalsbringnutrientsupfromdeepersoillayers,improvingsoilfertility.PlantrootsBacteriaandFungi(decomposers)1cmsoilformation:15years(warm,humidclimate)tohundredsofyearsOtherfactorsinfluencingsoil8SoilPropertiesTexture

質(zhì)地，礦物質(zhì)機(jī)械組成：

Variousparticlesaremixedinmanydifferentcombination,resultinginsoilclassification.

Determinedbythesizeofsoilparticles.Gravel石礫,d>2mmSand砂粒,0.05-2.0mmSilt粉砂粒,0.002-0.05mmClay粘粒,<0.002mmSoilPropertiesTexture質(zhì)地，礦物質(zhì)機(jī)9Toomanylargeparticlesleadstoextremeleaching.Toomanysmallparticlesleadstopoordrainage.Toomanylargeparticlesleads10Soilclassification:Clay粘土Silt淤泥Sand砂土

Loam壤土IdealforagricultureSoilclassification:Clay粘土11Structure-Referstothewayvarioussoilparticlesclumptogether. 土壤結(jié)構(gòu)：土壤顆粒的空間排列方式及穩(wěn)定程度，孔隙的分布及結(jié)合狀況。Howtochange?Measuredby?Friability-Soil’sabilitytocrumble.vs

粘結(jié)性，結(jié)持性Structure-Referstotheway12Ingoodsoils2/3oftheintra-soilspacescontainairaftertheexcesswaterhasdrained.Oxygenforrootcellsandsoilorganism.Ingoodsoils2/3oftheintra13Protozoa,nematodes,earthworms,insects,algae,bacteria,andfungiaretypicalinhabitantsofsoil.Protozoa,nematodes,earthworm14SoilProfileSoilProfile

土壤質(zhì)地剖面形態(tài)-Aseriesofhorizontallayersofdifferentchemicalcomposition,particlesize,andamountoforganicmatter.Horizon發(fā)生層-Eachrecognizablelayeroftheprofile.SoilProfileSoilProfile土壤質(zhì)地剖15SoilandItsUses土壤及其利用課件16OHorizon-Litter-Un-decomposedorpartiallydecomposedorganicmaterial.AHorizon-(Topsoil)Uppermostlayer-containsmostofthesoilnutrientsandorganicmatter.BHorizon-(Subsoil)Underneathtopsoil.Containslessorganicmatterandfewerorganisms,butaccumulatesnutrientsleachedfromtopsoil.-Poorlydevelopedindryareas.CHorizon-Weatheredparentmaterial-verylittleorganicmaterial.RHorizon-BedrockOHorizon-Litter-Un-decom17Mostcultivatedlandcanbeclassifiedaseithergrasslandorforestsoil.GrasslandSoils-UsuallyhaveadeepAHorizon-lowrainfalllimitstopsoilleaching.Ahorizonsupportsmostrootgrowth.ForestSoils-Topsoillayerisrelativelythin,buttopsoilleachateformsasubsoilthatsupportssubstantialrootgrowth.(Highrainfallareas)Mostcultivatedlandcanbecl18SoilandItsUses土壤及其利用課件19SoilErosion土壤侵蝕Erosion–Wearingawayandtransportationofsoil/topsoil

bywindandwater.Floodplain,delta,muddywaterafterstormEffect:leaveadegradedareaandburyvegetationwhereitsettles.SoilErosion土壤侵蝕Erosion–We20Naturalprocessacceleratedbyagriculturalpractice.Worldwide25.4,China5Billiontons/yrMadeworsebydeforestationanddesertification.High-techagriculturalpracticesonpoorlandincreaseerosionandleadtothetransportofassociatedfertilizersandpesticides.Naturalprocessacceleratedby21Mostcurrentagriculturalareaslosetopsoilfasterthanitcanbereplenished.Mostcurrentagriculturalarea22WinderosionMostcommonindry,treelessareas.Afterdesertification.Winderosion23SoilConservationWhentopsoilislost,fertilityisreducedordestroyed,thusfertilizersmustbeusedtorestorefertility.Raisesfoodcosts,andincreasessedimentloadsinwaterways.SoilConservationWhentopsoil24SoilandItsUses土壤及其利用課件25Watererosion–controlrunoffWatererosion–controlrunoff26ConservationPracticesContourFarming-Tillingatrightanglestotheslopeoftheland.Eachridgeactsasasmalldam.StripFarming-Alternatingstripsofcloselysowncropstoslowwaterflow.Terracing-Levelareasconstructedatrightanglestotheslopetoretainwater-goodforverysteepland.ConservationPracticesContour27SoilandItsUses土壤及其利用課件28WinderosionWindbreaks-Plantingoftreesorotherplantsthatprotectbaresoilfromthefullforceofthewind.Winderosion29TillagePlowinghasmultipledesirableeffects:Weedsandweedseedsareburied/destroyed.Cropresidueisturnedunder-decaysfasterandhelpsbuildsoilstructure.Leachednutrientsbroughtclosertosurface.Cooler,darkersoilisbroughttotopandwarmed.TillagePlowinghasmultiplede30ProblemEachtripoverthefieldisanaddedexpensetothefarmer,andatthesametimeincreasestheamountoftimethesoilisopentoerosionviawindorwater.ProblemEachtripoverthefiel31SoilandItsUsesSoilandItsUses32Outline:SoilFormationSoilPropertiesErosionSoilConservationOutline:SoilFormation33Land-Portionoftheworldnotcoveredbywater.Soil-Mixtureofminerals,organicmaterial,livingorganisms,air,andwater.Land-Portionoftheworldno34SoilFormationSoilformationbeginswithfragmentationofparentmaterial.母巖-Ancientrocklayerswithrecentdepositsfromlavaorglacialflows.

熔巖或冰河流動(dòng)Weathering

風(fēng)化-Factorsbringingaboutfragmentation破碎orchemicalchangeofparentmaterial.SoilFormationSoilformationb35MechanicalWeathering

物理風(fēng)化,原生礦物Resultsfromphysicalforcesreducingsizeofrockparticleswithoutchangingthechemicalnatureoftherock.FreezingandThawingCyclesErosionfromWindandMovingWaterMechanicalWeathering物理風(fēng)化,原生36ChemicalWeathering

化學(xué)風(fēng)化，次生礦物-Involvesthechemicalalterationofrockinsuchamannerthatitismorelikelytofragmentorbedissolved.Rockfragmentsexposedtoatmospheremayoxidize,orotherwisechemicallychange.ChemicalWeathering化學(xué)風(fēng)化，次生礦物37Humus-Decayingorganicmaterial.mixedwiththetoplayersofrockparticles,andsuppliessomeoftheneedednutrientstoplants.Increasethewater-holdingcapacityandinorganicnutrientsolubility(acidcond.)createscrumblysoilwhichallowsadequatewaterabsorptionanddrainage.Humus-Decayingorganicmater38Otherfactorsinfluencingsoilformation:Burrowinganimalsbringnutrientsupfromdeepersoillayers,improvingsoilfertility.PlantrootsBacteriaandFungi(decomposers)1cmsoilformation:15years(warm,humidclimate)tohundredsofyearsOtherfactorsinfluencingsoil39SoilPropertiesTexture

質(zhì)地，礦物質(zhì)機(jī)械組成：

Variousparticlesaremixedinmanydifferentcombination,resultinginsoilclassification.

Determinedbythesizeofsoilparticles.Gravel石礫,d>2mmSand砂粒,0.05-2.0mmSilt粉砂粒,0.002-0.05mmClay粘粒,<0.002mmSoilPropertiesTexture質(zhì)地，礦物質(zhì)機(jī)40Toomanylargeparticlesleadstoextremeleaching.Toomanysmallparticlesleadstopoordrainage.Toomanylargeparticlesleads41Soilclassification:Clay粘土Silt淤泥Sand砂土

Loam壤土IdealforagricultureSoilclassification:Clay粘土42Structure-Referstothewayvarioussoilparticlesclumptogether. 土壤結(jié)構(gòu)：土壤顆粒的空間排列方式及穩(wěn)定程度，孔隙的分布及結(jié)合狀況。Howtochange?Measuredby?Friability-Soil’sabilitytocrumble.vs

粘結(jié)性，結(jié)持性Structure-Referstotheway43Ingoodsoils2/3oftheintra-soilspacescontainairaftertheexcesswaterhasdrained.Oxygenforrootcellsandsoilorganism.Ingoodsoils2/3oftheintra44Protozoa,nematodes,earthworms,insects,algae,bacteria,andfungiaretypicalinhabitantsofsoil.Protozoa,nematodes,earthworm45SoilProfileSoilProfile

土壤質(zhì)地剖面形態(tài)-Aseriesofhorizontallayersofdifferentchemicalcomposition,particlesize,andamountoforganicmatter.Horizon發(fā)生層-Eachrecognizablelayeroftheprofile.SoilProfileSoilProfile土壤質(zhì)地剖46SoilandItsUses土壤及其利用課件47OHorizon-Litter-Un-decomposedorpartiallydecomposedorganicmaterial.AHorizon-(Topsoil)Uppermostlayer-containsmostofthesoilnutrientsandorganicmatter.BHorizon-(Subsoil)Underneathtopsoil.Containslessorganicmatterandfewerorganisms,butaccumulatesnutrientsleachedfromtopsoil.-Poorlydevelopedindryareas.CHorizon-Weatheredparentmaterial-verylittleorganicmaterial.RHorizon-BedrockOHorizon-Litter-Un-decom48Mostcultivatedlandcanbeclassifiedaseithergrasslandorforestsoil.GrasslandSoils-UsuallyhaveadeepAHorizon-lowrainfalllimitstopsoilleaching.Ahorizonsupportsmostrootgrowth.ForestSoils-Topsoillayerisrelativelythin,buttopsoilleachateformsasubsoilthatsupportssubstantialrootgrowth.(Highrainfallareas)Mostcultivatedlandcanbecl49SoilandItsUses土壤及其利用課件50SoilErosion土壤侵蝕Erosion–Wearingawayandtransportationofsoil/topsoil

bywindandwater.Floodplain,delta,muddywaterafterstormEffect:leaveadegradedareaandburyvegetationwhereitsettles.SoilErosion土壤侵蝕Erosion–We51Naturalprocessacceleratedbyagriculturalpractice.Worldwide25.4,China5Billiontons/yrMadeworsebydeforestationanddesertification.High-techagriculturalpracticesonpoorlandincreaseerosionandleadtothetransportofassociatedfertilizersandpesticides.Naturalprocessacceleratedby52Mostcurrentagriculturalareaslosetopsoilfasterthanitcanbereplenished.Mostcurrentagriculturalarea53WinderosionMostcommonindry,treelessareas.Afterdesertification.Winderosion54SoilConservationWhentopsoilislost,fertilityisreducedordestroyed,thusfertilizersmustbeusedtorestoref