fj人类面临的全球性环境问题与可持续发展

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1、Page6of6SOIL5813_____________________________________________________________________________________SOIL5813Soil-PlantNutrientCyclingandEnvironmentalQualityFirstHourExamFebruary25,2004Name:______________Miscellaneous:TFTheadverseeffectsofweathercanbeovercomebyapplyingm

2、oreNTFBiaserrorisconsidered“accuracy”whileRandomerrorismoreintunewith“precision”TFNH4ismostlikelytoaccumulateinsemi-aridenvironmentsTFNitrogenuseefficiencyforworldwidecerealproductionaverages33%TFWorkbyFrancisetal(1993)reportedthatplantNlossesaccountedfor52to73%oftheuna

3、ccounted-forNin15NbalancecalculationsTFDenitrificationinsoilsiscontrolledlargelybythesupplyofwater-solubleorreadilydecomposableorganicmatterTFDenitrificationlossesaregenerallygreaterwhenNisappliedinconventionaltillsoilsascomparedtozerotillsoils.TFThevastmajorityofNOxisr

4、eleasedasnitricoxide,NO,whichconvertstonitrogendioxide,NO2,withinminutesbyreactionwithozoneandperoxyradicals.NO2isrecycledtoNObyphotolysis.1.WhatisthecurrentINSEYindexusedinwinterwheatbyOSU(formula),andwhatdoesINSEYstandfor?Defineallcomponents.WhatdoesINSEYdo?INSEY=(NDV

5、IcollectedsomewherebetweenFeekes4-6/daysfromplantingwhereGDD>0)NDVI=(NIR-red)/(NIR+red)GDD=(Tmin+Tmax)/2–4.4°CINSEYisanindexusedtopredictwheatgrainyieldfromsensormeasurementscollectedmid-seasonSTUDENTQuestions1.Explainwhynitrificationcanbeconsidereda“goodandevil”process

6、inthenitrogencycle.Good:NO3-istheproductofnitrificationwhichisanavailableformofNtakenupbyplants.Page6of6SOIL5813_____________________________________________________________________________________Evil:NO3-isalsoasubstrateinthedenitrificationprocesswhichconvertsitthroug

7、haseriesofintermediatestonitrogengas(unavailableformofnitrogenforplantsuse).NO3-isalsotheformofNthatcanbelostbyleaching.2.Whyisnitrogenlimitingdespitethefactthatitmakesup78%ofatmosphere?Nitrogenremainslargelylockedintheatmosphereandonlysmallfractionofthisresourceexistsi

8、naformthatcanbeabsorbedbygrowingplants,animalsandultimatelybyhumans.3.Whatarethepossibleimplicationsoflongterm