桉树对土壤肥力影响

1、桉树对土壤肥力的影响1桉树的相关概述relatedoverviewoftheeucalyptus1.1桉树简介eucalyptusintroduction桉树是桃金娘科桉树属的总称，属常绿乔木。树皮粗厚而宿存或平滑而年年脱落，有挥发性芳香油，同松树、杨树一起成为全球最速生、经济价值最大、生态和社会效益最高的三大树种。一百多年前我国开始引种桉树，初期只是小规模的引种试验或观赏性质的树种；近年来桉树人工林的规模迅速发展，国内总的种植面积已达154万公顷,仅次于印度和巴西，主要分布在两广地区、云贵川地区、福建和海南等长江以南地区。Thefloorboardoftheeucalyptusismyrta

2、ceaeeucalyptus,evergreentrees.Barkthickandpersistentorsmoothandlossyearafteryear,haveavolatilebalmyoil,becometheworldsfast-growingwithpine,poplar,theeconomicvalueofthethreelargestandmostecologicalandsocialbenefits.EarlyonehundredyearsagobegantointroductionofeucalyptusinChina,onlysmall-scaleintroduct

3、ionexperimentorornamentalqualitytreespecies;Thesizeoftherapiddevelopmentofeucalyptusplantationinrecentyears,domestictotalplantingareaof1.54millionhectares,issecondonlytoIndiaandBrazil,aremainlydistributedinareas,YunGuiChuanareasofguangdong,fujianandhainanregionsouthoftheYangtzeriver.桉树用途eucalyptuspu

4、rposes桉树的经济效益比较客观,主要用在以下方面:第一个重要的用途就是纤维材,桉树造纸广泛的应用在我国江淮一带的纸浆厂,桉树纤维材还可以用于生产纤维板和刨花板,近年来华南的纤维板厂正逐步建立和完善并正向环保型纤维板生产方向发展;第二桉树是质量上成外部美观的家具装饰用材,多用于高档次的建筑物和室内装饰,不但质量好,而且十分美观;第三桉油是用途良好的医药和香料原料,其中史密斯桉、直杆蓝桉、亮果桉等是产油较高的树种。最后桉树在园林绿化和生态林建设方面的应用十分广泛。Theeconomicbenefitsofeucalyptusismoreobjective,mainlyusedinthefoll

5、owingaspects:thefirstisimportantusefibermaterial,eucalyptusiswidelyusedinpaperpulpmillofjianghuaiareainourcountry,eucalyptusfibrematerialcanalsobeusedforproductionoffiberboardandparticleboard,fiberboardfactoryinsouthChinainrecentyearsisgraduallyestablishandperfectandisenvironmentallyfriendlyfiberboa

6、rdproductiondirection;Secondonthequalityofeucalyptusisintoexternalbeautifulfurniture,decorationmaterialusedinhigh-gradebuildingandinteriordecoration,notonlyofgoodquality,andverybeautiful;Thirdeucalyptusoilisusegoodrawmaterialmedicineandspices,includingeucalyptus,straightrodSmithiseucalyptusglobulus,

7、brightfruitsuchaseucalyptusoilhightreespecies.Finallyeucalyptusinlandscapingandtheapplicationoftheconstructionofecologicalforestisveryextensive.桉树的影响theinfluenceofeucalyptus桉树人工林大面积发展可能会导致土地肥力衰退,这种衰退主要表现在两方面:一方面桉树因其速生性,其生长过程需要由土地供给大量的养分,因而对土壤肥力的消耗较大;另一方面,桉树林地的管理方式不科学,如不论土壤条件,改变了土壤结构,减少了地表的植被覆盖,进而导致林

8、地土壤水分下渗量减少和水土流失的严重问题。Couldleadtowidespreaddevelopmentofeucalyptusplantationlandfertilitydecline,thedeclineismainlymanifestedintwoaspects:ontheonehand,eucalyptusbecauseitsspeedis,thegrowthprocessoflandsupplyhastobealotofnutrients,thusfortheconsumptionofsoilfertility;Eucalyptusforest,ontheotherhand,th

9、emanagementisnotscience,suchaswhethersoilconditions,changethesoilstructure,reducedthesurfacevegetationcover,leadingtoreducedthevolumeofforestlandsoilwaterinfiltrationandtheseriousproblemofsoilerosion.土壤肥力2thesoilfertility土壤肥力的界定definitionofsoilfertility土壤是林业生产的首要因素,常以N、P、K和有机质等养分的含量来衡量土壤肥力的高低。土壤肥力是土

10、地生产力的基础,土壤肥力是土壤为植物生长提供营养和环境条件的能力,是土壤基本性质的综合体现。苏联土壤学家威廉士对土壤肥力的定义是:“土壤在植物生活的全过程中同时又不断地供给植物以最大量的有效养分及水分的能力”;现代学者孙波、陈金林等人将土壤肥力定义为:“内外在因素（光照、温度与土壤物理条件等）都适合特定植物生长时,土壤以适当的量和平衡的比例向这种植物供应养分的能力。”Soilisthefirstfactorofforestryproduction,oftennutrientssuchasN,P,Kandorganicmattercontenttomeasurethelevelofsoilfer

11、tility.Soilfertilityisthebasisoflandproductivity,soilfertilityistheabilitytoprovidenutrientsforplantgrowthandenvironmentalconditions,istheintegratedembodimentofsoilbasicproperties.SovietsoilscientistWilliamJamestothefertilityofsoilisdefinedas:soilinthewholeprocessofplantlifeandcontinuallysupplyplant

12、swiththemostlargeamountsofavailablenutrientsandmoisturecapacity;Sunbo,modernscholarsChenJinlinetal.Soilfertilityisdefinedas:absurdismfactors(light,temperatureandsoilphysicalconditions,etc.)isfitforaparticularplantgrowth,soilintheappropriateamountandbalancetheproportionoftheabilitytosupplynutrientsto

13、theplant.土壤肥力评价指标thesoilfertilityevaluationindex一般来说土壤肥力与健康的诊断主要有描述土壤健康的描述性分析和定量研究的分析性指标,具有定量单位的分析性指标是学术研究中评价土壤肥力的主要标准,分析性指标主要包括物理指标、化学指标和生物指标,在评价土壤肥力时根据不同的土壤和评价目的,选择性的对指标进行取舍组合。学者研究调查指出合理评价土壤肥力应该参考以上指标进行综合测量。Ingeneralthesoilfertilityandhealthdiagnosisismainlydescribethesoilhealthydescriptiveanalysi

14、sandquantitativeanalysisoftheindicators,withthequantitativeanalyticalindexoftheunitisthemainstandardofevaluationofsoilfertilityintheacademicresearch,analyticalindicatorsmainlyincludephysical,chemicalandbiologicalindicators,accordingtodifferentsoilandwhenevaluatethesoilfertilityevaluationpurpose,sele

15、ctivelytochoosecombinationindex.Scholarsresearchpointsoutthatthereasonableevaluationindexofsoilfertilityshouldrefertotheabovecomprehensivemeasurement.桉树对土壤肥力的影响Threeeucalyptusimpactonsoilfertility对土壤物理性质的影响impactonsoilphysicalproperties土壤容重大小能够反映土壤的通透性以及根系伸展的阻力状况,土壤容重容重大小在很大程度上影响着植物根系的生长、土壤动物和微生物的活动

16、。土壤水分是土壤物质转化和代谢的重要因素,土壤中的毛管水可以移动,对于植物是最有效的水分,很大程度影响着植物的生长发育;经过笔者实地定期调查显示在同一层级的桉树人工林地,随着树龄增长,土壤的容重逐渐减少,而土壤的最大持水量有所增加;土壤孔隙主要包括毛管孔隙和非毛管孔隙,其中毛管孔隙将细小土粒排列形成小的孔隙,有利于土壤水分被毛管引力吸持,因此这种孔隙决定了土壤的蓄水性;非毛管孔隙则是由较大土粒疏松排列形成的,这类孔隙对水分吸持力较小,进入孔隙的水分会很快淋失,其决定了土壤的通气性和排水情况。笔者实地定期调查在同一层级的桉树人工林地,随着树龄的增长,土壤的孔隙度逐步增加,改善了土壤的通气条件,但

17、是随着土层深度的增加,土壤通气良好的状况逐渐降低。综上所述,桉树人工林的大规模种植可以在一定程度上改良土壤的容重、土壤的含水量以及土壤的孔隙度,但是这种对土壤物理性质的改善程度是需要进一步验证的。Sizecanreflectthepermeabilityofsoilandsoilbulkdensityrootsstretchingresistancecondition,soilbulkdensitysizetoalargeextentaffectthegrowthofplantroots,soil,animalandmicrobialactivity.Soilmoistureisanimpor

18、tantfactorofsoilmaterialandmetabolic,capillarywatercanbemovedfromthesoil,toplantisthemosteffectivemoisture,greatlyaffectplantgrowthanddevelopment;Throughfieldsurveyonaregularbasisatthesamelevelofeucalyptusplantationforest,alongwiththeagegrowth,soilbulkdensitygraduallydecreased,andsoilmaximummoisture

19、capacityincreased;Soilporosityismainlyincludingcapillaryporosityandcapillaryporosity,capillaryporositywillfinesoilparticlesarrangementformsmallpore,isbeneficialtosoilwaterbycapillaryforceholding,sotheporedeterminesthewaterstorageofsoil;Thecapillaryporesareformedfromlargesoilgrainloosearrangement,suc

20、hporosityonthemoistureholdingforceissmall,intotheporewaterwillsoonleaching,determiningthesoilairpermeabilityanddrainage.Theauthorfieldsurveysonaregularbasisatthesamelevelofeucalyptusplantationforest,asthegrowthoftheage,soilporosityincreasedgradually,theimprovedsoilaerationconditions,butwiththeincrea

21、seofsoildepth,soilaerationgoodconditiongraduallyreduced.Tosumup,thelarge-scalecultivationofeucalyptusplantationcantoacertainextent,improvesoilbulkdensity,soilwatercontentandsoilporosity,buttheimprovementonsoilphysicalpropertiesisneedfurthervalidation.对土壤化学性质的影响impactonsoilchemicalproperties土壤中的氮是植物生

22、长发育所需要的营养元素之一氮元素的供应容量反映土壤的总体水平,其中碱解氮体现了一定时期内N素的供应情况,调查显示桉树林地的土壤全N和水解N随着林龄的增加而逐渐减少,对同一林龄的土壤随土壤层次的增加全N、水解N含量逐渐降低。与对照（混交林）相比,桉树人工林的土壤全N、水解N含量均小于混交林含量。ofnitrogeninthesoilisoneofthenutrientsneededforplantgrowthanddevelopmentreflectstheoveralllevelofsoilnitrogensupplycapacity,thealkalinehydrolysisnitrogen

23、embodiesthesupplysituationofNelementincertainperiodoftime,accordingtoasurveyofeucalyptuswoodlandsoiltotalNandhydrolyticNdecreasegraduallyalongwiththeincreaseofforestage,onthesameplantationageofsoilwithsoillayersincreasedtotalN,hydrolyticNcontentgraduallydecreased.Comparedwiththecontrol(mixed),eucaly

24、ptusplantationsoiltotalN,hydrolyticNcontentwerelessthanthemixedcontent.磷对于植物生长具有很大的营养生理功能植物所需要的磷主要来自土壤,然而土壤有效磷只占全磷量的极小部分,有效磷和全磷量之间并没有相关性,因此土壤全磷量并不是土壤磷素供应水平衡量指标。实地调查结果显示,对于同一层级的土壤全磷量随着林龄的增加逐渐减少,同一树龄的土壤随土壤层次的增加也逐渐降低;而对有效磷量的影响并不明显。phosphorusforplantstogrowverynutritionphysiologicalfunctionofphosphorusm

25、ainlyfromplantsneedsoil,however,availablesoilphosphorusaccountsforonlysmallpartoftheamountoftotalphosphorus,effectivephosphorusandtotalphosphorusamountisnocorrelationbetween,sothequantityofsoiltotalphosphorusisnotmeasurethesoilpsupplylevel.Fieldsurveyshowsthatforthesameleveloftotalphosphoruscontenti

26、nsoilincreasedwiththeincreaseofforestagegraduallydecreases,withtheincreaseofthesoillayersofthesoilisofthesameoldgraduallyreduce;Andaffectsthequantityofeffectivephosphorusisnotobvious.钾的调节催化作用加速了植物对二氧化碳的同化促进碳水化合物的转移以及蛋白质的合成,钾素增强植物的抵抗力,是植物生长必须营养元素之一。钾素能增强植物的抗病力,土壤中的速效钾是钾素的现实供应指标。调查显示,速效钾和全钾的含量随着林龄的增加递

27、减明显,这表明桉树的生长对土壤全钾和速效钾的均显着影响。theregulationofpotassiumcatalystacceleratedtheplantassimilationofco2promotesthetransferofcarbohydrateandproteinsynthesis,potassiumenhanceplantresistance,isoneofmustnutrientelementsforplantgrowth.Potassiumcanenhancethediseaseresistanceofplants,andthesoilavailablekisthereal

28、ityofpotassiumsupplyindicators.Accordingtothesurvey,rapidly-availablepotassiumandtotalpotassiumcontentisdiminishingwiththeincreaseofforestage,suggestingthatthegrowthofeucalyptusonsoiltotalpotassiumandavailablepotassiumhavesignificantinfluence.虽然土壤中微量元素的含量仅有万分之几,对植物正常生长发育起着不可忽视的作用直接影响到有机体的代谢过程;微量元素主要

29、由酶、维生素和生长激素等组成的成分。在桉树人工林的实地调查中显示,林地土壤微量元素的含量呈现递减趋势,其中有效Fe和有效Mn的含量在0-20cm土层处随着林龄的增加而减少,然而不同树龄的土壤有效Fe含量变化不显着;有效Cu的含量在40-60cm土层处的含量无明显变化,而其余土层的含量均随林龄的增加而减少而有效Zn的含量在土层的并无明显变化。热风炉总之,桉树人工林的生长对土壤有效微量元素有一定的影响。althoughthecontentoftraceelementsinsoil,onlyveryfewtotheplantnormalgrowthanddevelopmentplaysaconsid

30、erableroledirectlyinfluencesthemetabolismoforganismsprocess;Traceelementsismainlycomposedofenzymes,vitaminsandgrowthhormone,etc.Fieldsurveyineucalyptusplantation,woodlandsoiltraceelementcontentpresentatendencyofdecreasing,theeffectivecontentofFeandMnin020cmsoillayerincreasedwiththeincreaseofforestag

31、edecreased,soileffectiveFecontentindifferenttreeage,however,changeisnotsignificant;EffectivecontentofCuin40to60cmsoillayerhasnoobviouschangeincontent,whiletherestofthecontentofsoildecreasewiththeincreaseofforestage;Andeffectivezinccontentinsoilandnoobviouschange.Tosumup,thegrowthofeucalyptusplantati

32、ononthesoileffectivetraceelementshaveacertaineffect.3.3对土壤生物性质的影响3.3impactonsoilbiologicalproperties土壤微生物是森林生态系统的重要组成元素它在土壤中的含量和活动状况反映了土壤肥力,也是土壤中生物活性的具体体现。调查显示桉树林地土壤微生物以细菌居多,且桉树林地土壤中的微生物含量随着林龄的增长而减少其中细菌和放线菌在同一林龄40-60cm土层含量最多,20-40cm土层处含量最少,这可能与根系分布状态有关系。而同一树龄真菌的含量0-20cm土层处含量最多,而40-60cm土层处土壤微生物数量最少,这

33、种分布状态与土层腐殖质含量相关;行星齿轮减速机soilmicroorganismsisforestecologicalsystemisanimportantelementofitscontentandactivityinthesoilreflectthesoilfertility,andalsotheembodimentofthesoilbiologicalactivity.Eucalyptusforestlandsoilmicrobesinthemajoritywithbacteria,accordingtothesurveyandeucalyptusforestlandsoilmicrob

34、escontentalongwiththeincreaseofforestageandreduce;Ofbacteriaandactinomycetesinthesameforestage40to60cmsoillayercontent,mostcontentofatleast20-40cmsoillayer,whichmayhaverelationswithrootsystemdistribution.Overthesameoldfungiin020cmsoillayeratmost,and40-60cmsoillayersoilmicrobialquantityminimum,thisdi

35、stributionstateassociatedwiththesoilhumuscontent;土壤酶是土壤中具有生物活性的蛋白质,有助于土壤中的物质转化酶活性高低是土壤肥力的衡量指标之一。滴灌带调查分析结果表明:蛋白酶过氧化氢酶、脲酶在桉树人工林土壤的不同层次之间有着显着影响;其中过氧化氢酶不同林龄之间达到了显着差异,而脲酶不同林龄之间并无显着性差异;即桉树林的生长降低了土壤蛋白酶、过氧化氢酶有较大的影响而对土壤脲酶、磷酸酶的影响较小。rainfalldistributionon10-12soilenzymeisproteinwithbiologicalactivityinthesoil,tothematerialtransformationinsoilenzymeactivityisoneoftheindicatorsofsoilfertility.Investigationandanalysisresultsshowedthatth