施肥对水曲柳和落叶松细根动态影响的的研究

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1、东北林业大学博士学位论文也分别占到60％左右。研究分析表明，两树种各径级细根生长可能要受到树种自身因素和环境因素的相互控制，而不同径级细根死亡则可能主要受外环境因素的作用。5．细根周转估计表明：施肥使两树种不同土层、不同径级细根周转加快；两树种对照区和施肥区细根周转随土层增加而变小，随直径增大而减小，且施肥区大于对照区；两树种间细根周转也存在差异，落叶松要大于水曲柳。综合分析表明，(1)施肥对水曲柳和落叶松人工林细根分布、生长和死亡影响不明显，但施肥加快了两树种细根周转：(2)水曲柳和落叶松两树种具有不同的生物学特性。两树种细根的

2、生长可能受树种内在因素和外环境因素的相互作用控制。关键词水曲柳；落叶松；施肥；细根；生长；周转；微根管AbstractFinerootisamajororganoftreesinabsorbingwaterandnutrition．Theproductionandturnoveroffinerootinforestecosystemsplayanimportantroleinterrestrialcarbonandnutritioncycles．ByusingMinirhizotron，thedistribution，produc

3、tion，mortalityandturnoveroffinerootamongdifferentsoildepthanddifferentdiameterwereinvestigatedneartwoyearsin18yearsoldpureManchurianash(Fraxinusmandshurica)andDavurianlarch犯arixgmelinii)plantations，whichwerefertilizedandlocatedonthesamestandconditions．Atthesametime，so

4、iltemperature，soilmoistureandnitrogenavailabilitywerealsomeasuredintheseplantations．Theresultswereshowedasfollows：1．Theresultsofstudyingonthedistributionoffinerootsuggested：(1)Asfortwotreesspeciesinfertilizedandcontrolledplots，thenumberoffinerootandrootlengthdensitywe

5、realldecreasedwithsoildepthincreased，thenumberoffinerootofManchurianashwasmorethanthatofDavurianlarch，finerootlengthdensityofManchurianashwasalsohigherthanthatofDavurianlarch．Bothoffinerootnumberandrootlengthdensityinfertilizedplotswerelessthanthoseincontrolledplots．M

6、ostofManchurianashfinerootoccurredinspringandsummer,butDavurianlarchfinerootmainlyoccurredinsummer．Forbothoftreesspeices，thefinerootlengthdensitywasnotsignificantlyaffectedbyfertilization，andwasalsonodifferenceamongdiverseseasons；(2)Fertilizationdidn’tsignificantlyaff

7、ectfinerootdiameterforManchurianashandDavurianlarchfineroot．Consideringtwotreesspeciesinfertilizedandcontrolledplots，themeanrootdiameterofManchurianashwasthinnerthanthatofDavurianlarch．AlthoughthediameterofManchurianashfinerootwassigllificantlychangedwithdifferentseas

8、ons，andbecamethickerindeepsoilthaninshallowsoil，thisstatusdidn’texhibitforDavurianlarchfineroot．2．Theexperimentoffinerootdyn