简介：Inthisstudy,wecomparedtheaerialelectrostaticspraywithnon-electrostaticspraybyhelicopterR44andfixed-wingaircraftY5Bequippedwithanown-madeaerialelectrostaticsprayingsystem.Theresultsshowedthatthespraydepositsontargetsandleavesoftreecrownswerenotableenhancedcomparingwiththenon-electrostaticandconventionalaerialspray.Thespraydepositswerefine,uniformandthedensitieswere1.0-1.75timeshigherthanthenon-electrostaticspray.DepositrateoftheelectrostaticsprayonthebacksofleavesbyhelicopterR44was2.15timesofthenon-electrostatic,and3.31timesoftheconventionalaerialspray.ThedepositrateoftheelectrostaticsprayonthebacksofleavesbytheY5Bwas2.38timesofthenon-electrostatic,and3.44timesoftheconventionalaerialspray.

简介：Nitrogendepositionimposesimportantimpactonthefunctionandthestabilityofforestcarbonsequestration.Thispaperreviewedtheresearchadvancesintheincreasingresponseofforestcarbonsequestrationtonitiogendeposition,describedtheapplicationprospectsofstablecarbonisotopetechniqueintheresearchfield.Andfinallythispaperpointedoutthat,ontheconditionthatnitrogendepositionrises,ontheallocationofforestphotosyntheticproductsandthechangeinsoilcarbonturnoverratearethetwohotspotsinthefuturecarboncyclingresearch.

简介：ThenitrogendepositionexperimentsonCinnamomumcamphoraplantationofHunanprovincialbotanicalgardenweresimulatedfromJunethe7thtoOctoberthe7th,2010,thenitrogendepositionlevelswasrespectivelyascontrol(CK,0g·m-2a-1),lownitrogen(LN,5g·m-2a-1),mediumnitrogen(MN,15g·m-2a-1)andhighnitrogen(HN,30g·m-2a-1).ThesoilrespirationspeedandsoilsurfacetemperatureandthesurfacewatercontentofthesoilweredeterminedbyLI-8100measuringinstrument.TheresultsshowthattheaveragevaluesofsoilrespirationspeedwereCK(4.09±0.66μmol·m-2s-1),LN(2.39±029μmol·m-2s-1),MN(2.18±0.19μmol·m-2s-1),HN(2.28±0.25μmol·m-2s-1),andthetreatmentoftheCKwasobviouslyhigherthantheotherthreetreatments（P<0.01）.Withdifferentnitrogenconcentrationsdepositiontreatments,theQ10（temperaturesensitivitycoefficients）forsoilrespirationofCK,LN,MNandHNtreatmentswere1.84,1.71,1.83and1.56.Itwaspositivecorrelationbetweentherespirationspeedandthesurface（≤10cm）temperatureoftestedsoil.Itwasnegativecorrelationbetweentherespirationspeedandthesurface（≤5cm）watercontentoftestedsoil（P>0.05）.Volumetricwatercontentof5-cmsoilwasbetween0.2666-0.2944(m3·m-3),andthemonthlycontentdidnotvarytoomuchduringtheresearchperiod（1.8%-9.4%）.ThefindingssuggestthattheinitialstageofnitrogendepositionobviouslyinfluencedthesoilrespirationofC.camphoraplantation.

简介：Background:RapideconomicdevelopmentinChinahasresultedinanincreaseinsevereairpollutionincitygroupssuchastheBeijing-Tianjin-HebeiMetropolitanRegion.PM2.5(fineparticleswithanaerodynamicequivalentdiameterof2.5μmorless)isoneofthemostimportantpollutants.Thedepositionprocessisanimportantwayofremovingparticlesfromtheair.Toevaluatetheeffectofanurbanforestonatmosphericparticleremoval,aconcentrationgradientmethodwasusedtomeasurethedepositionvelocitiesofwater-solubleinorganicsinPM2.5intwonationalforestparksinBeijing,China.Thefollowingeightwater-solubleinorganicionsinPM2.5wereinvestigated:sodium,ammonium,potassium,magnesium,calcium,chloride,nitrate,andsulfate.Methods:SamplesweretakenfromtwositesinBeijingfromthe7thtothe15thMay,2013.Theconcentrationsofwater-solubleinorganicionswereanalyzedwithionchromatography.Weusedtheconcentrationgradienttechniquetoestimatethedepositionfluxandvelocity.Todeterminetherelationshipsbetweenleaftraitsandparticleaccumulation,typicalleafsamplesfromeachselectedspecieswerestudiedusingscanningelectronmicroscopy.Results:ThetotaldepositionfluxandtotaldepositionvelocityduringthedaytimewerehigherthanthoseatnightSulfateshowedthebiggestdepositionfluxandvelocityatbothstudysites,whereastheotherionsshoweddifferenttrendsateachsite.Resultfromhigherproportionofconiferoustobroadleavedtrees,thetotaldepositionfluxoftheeightionsmeasuredinJiufengNationalForestParkwasgreaterthanthatinOlympicForestPark.Conclusions:Thedepositionvelocitywasaffectedbymeteorologicalconditionssuchaswindspeed,temperature,andhumidity.Thedepositionvelocitywasalsoinfluencedbytreespecies.Thesurfaceofplantsisanimportantfactorinfluencingparticledeposition.Theresultsofthisstudymayhelpinassessingtheeffectsofforestrysystemsonparticleremovalandprovideevidenceforurbanairpollutioncontr

简介：Elevatedatmosphericnitrogen(N)depositionhasbeendetectedinmanyregionsofChina,butitseffectsonsoilNtransformationintemperateforestecosystemsarenotwellknown.WethereforesimulatedNdepositionwithfourlevelsofNadditionrate(N0,N30,N60,andN120)for6yearsinanold-growthtemperateforestinXiaoxing’anMountainsinNortheasternChina.WemeasuredgrossNtransformationratesinthelaboratoryusing15NtracingtechnologytoexploretheeffectsofNdepositiononsoilgrossNtransformationstakingadvantageofNdepositionsoils.NosignificantdifferencesingrosssoilNtransformationrateswereobservedafter6yearsofNdepositionwithvariouslevelsofNadditionrate.ForallNdepositionsoils,thegrossNH4+immobilizationrateswereconsistentlylowerthanthegrossNmineralizationrates,leadingtonetNmineralization.Nitrate(NO3-)wasprimarilyproducedviaoxidationofNH4+(i.e.,autotrophicnitrification),whereasoxidationoforganicN(i.e.,heterotrophicnitrification)wasnegligible.Differencesbetweenthequantityofammonia-oxidizingbacteriaandammonia-oxidizingarchaeawerenotsignificantforanytreatment,whichlikelyexplainsthelackofasignificanteffectongrossnitrificationrates.GrossnitrificationratesweremuchhigherthanthetotalNO3-consumptionrates,resultinginabuild-upofNO3-,whichhighlightsthehighriskofNlossesviaNO3-leachingorgaseousNemissionsfromsoils.ThisresponseisoppositethatoftypicalN-limitedtemperateforestssufferingfromNdeposition,suggestingthattheinvestigatedold-growthtemperateforestecosystemislikelytoapproachNsaturation.