简介：Theleachingandredistributionofnutrientsinthesurfacelayerof4typesofredsoilsinSoutheastChinawerestudiedwithalysimeterexperimentunderfiledconditions.Resultsshowedthattheleachingconcentratedintherainyseason(fromApriltoJune).Generally,theleachingofsoilnutrientsfromthesurfacelayerofredsoilswasintheorderofCa>Mg>K>NO3-N,Infertilizationtreatment,thetotalamountofsoilnutrientsleachedoutofthesurfacelayerinaredsoilderivedfromgranitewasthehighestinallsoils.Theuptakebygrassdecreasedtheleachingoffertilizerionsinsurfacelayer,particularlyforNo3-N,SoiltotalNandexchangeableK,CaandMginthesurfacelayerdecreasedwithleachingandgrassuptakeduringthe2yearswithoutnewfertilizationofurea,Ca(H2PO4)2,KCl,CaCO3andMgCO3,Camovedfromtheapplicationlayer(0-5cm)offertilizerandaccumulatedinthe10-30cmdepthinthesoilsstudiedexceptthatdervedfromquaternaryredclay.ThedeficiencyofsoilexchangeableKwillbecomeaseriousdegradationprocessfacingtheSoutheastChina.

简介：Background:Understoryplantsrepresentsthelargestcomponentofbiodiversityinmostforestecosystemsandplaysakeyroleinforestfunctioning.Despitetheirimportance,theinfluenceofoverstory-layercompositiononunderstoryplantdiversityisrelativelypoorlyunderstoodwithindeciduous-evergreenbroadleavedmixedforests.Theaimofthisworkwastoevaluatehowtreeoverstory-layercompositioninfluencesonunderstory-layerdiversityinthreeforesttypes(monospecificdeciduousNothofaguspumilio(Np),monospecificevergreenNothofagusbetuloides(Nb),andmixedN.pumilio-N.betuloides(M)forests),comparingalsobetweentwogeographicallocations(coastandmountain)toestimatedifferencesatlandscapelevel.Results:Werecorded46plantspecies:4ferns,12monocots,and30dicots.Canopy-layercompositioninfluencestheherb-layerstructureanddiversityintwodifferentways:whilemixedforestshavegreatersimilaritytoevergreenforestsintheunderstorystructuralfeatures,deciduousandmixedweresimilarintermsofthespecificcompositionofplantassemblage.Deciduouspurestandswerethemostdiverse,meanwhileevergreenstandswereleastdiverse.Lackofexclusivespeciesofmixedforestcouldrepresentatransitionwhereevergreenanddeciduouscommunitiesmeetandintegrate.Moreover,landscapehasamajorinfluenceonthestructure,diversityandrichnessofunderstoryvegetationofpureandmixedforestslikelyassociatedtothemagnitudeandfrequencyofnaturaldisturbances,wheremountainforestnotonlyhadhighestherb-layerdiversitybutalsomoreexclusivespecies.Conclusions:OurstudysuggeststhatmixedNothofagusforestsupportscoexistenceofbothpuredeciduousandpureevergreenunderstoryplantspeciesanddifferentassemblagesincoastalandmountainsites.Maintainingthemixtureofcanopypatchtypeswithinmixedstandswillbeimportantforconservingthenaturalpatternsofunderstoryplantcompositioninsouthernbeechmixedforests.

简介：Alargenumberofplantremainswerediscoveredintheancient-woodslayerofZhujiajianIsland,ZhejiangProvince.Thereweresomethicktrunks,completelaminas,fruit,seedsandsoon.Accordingtoradiocarbontestsconductedforplantremains,theancient-woodslayerhasbeendatedbacktoabout8750-6200years,andthevegetationwasasubtropicalevergreenanddeciduousbroad-leavedmixedforestsontheislandinthepast.Inthemiddleoftheancient-woodslayer,twograinsofwildricewereexploredaccidentally,whichareOryzarufipogon,alongwiththefruitandseedsofsomewaterplants,suchasCeratophyllumdcmcrsum,C.oryzetoum,Euryalefetox,Trapaincisavar.quadricaudata,Scirpusyagaraandsoon.Theremightbemarshysoilandapondinancientforestvegetationfromwherethegrainsofwildriceandhydrophyticfruitwerefound.ItisoftremendousimportancetostudytheoriginofwildriceinChina.

简介：稀少树的土地是典型陆地之一并且能在边界层气象学被看作一典型不平的表面。许多陆地能在规模的看法和象agroforest那样的粗糙元素的分发特征被分类进客气的表面，散布种或成长的树，无树平原等等。在稀少树的土地的表面边界层的结构被分析并且参数，磨擦velocityu?并且粗糙长度zo基于精力平衡法律和另外的物理假设被推出。模型与风隧道实验和域大小的数据同意很好。