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1、2006年10月中国水土保持科学Vol.4No.54(5):5055ScienceofSoilandWaterConservationOct.2006大兴安岭林区落叶松林地不同发育阶段土壤肥力演变与评价陈立新,肖洋(东北林业大学林学院,150040,哈尔滨)摘要以大兴安岭林区不同发育阶段兴安落叶松人工林和天然次生林为研究对象,采用野外调查和定量分析相结合的方法,对林地土壤有机质、土壤腐殖质组成、土壤酸度指标及其主要养分含量的变化进行测定和分析。利用主成分分析的方法,以各主成分特征贡献率为权重,加权计算各林地土
2、壤肥力综合指标值。结果表明:随着林龄的增长,不同发育阶段落叶松人工林土壤酸度总体呈现升高的趋势,土壤有酸化的迹象;全磷和速效钾呈现降低的趋势;有机质、水解氮、胡敏酸和胡敏素含量在近熟林略有升高,但总体呈现降低的趋势。土壤肥力评价结果为:天然林>幼龄林>近熟林>中龄林>成熟林,即随着林龄的增长,土壤肥力迅速下降,其主要原因是林地凋落物分解缓慢。因此,建议通过适度提高林地抚育强度,调整群落结构,增加林地光照,诱导天然阔叶树种进入,形成针阔混交林的调控措施,调节落叶松人工纯林凋落物分解与积累的矛盾,以维持地力平衡和
3、提高林地生产力。关键词兴安落叶松;土壤酸度;土壤腐殖质组成;土壤肥力EvolutionandevaluationofsoilfertilityinforestlandinLarixgmeliniiplantationsatdifferentdevelopmentstagesinDaxinganlingforestregionChenLixin,XiaoYang(CollegeofForestry,NortheastForestryUniversity,150040,Harbin,China)AbstractT
4、heresearchobjectwasbasedonlarch(Larixgmelinii)plantationsatdifferentdevelopmentstagesandnaturalsecondaryforestintheforestareaofDaxinganlingMountains.Usingthecombinedmethodsoffieldinvestigationandquantitativeanalysis,thechangesofsoilorganicmatter,thecomposit
5、ionofsoilhumus,soilacidityindicesandtheirchiefnutritioncontentweredeterminedandanalyzed.Bythemethodsofprincipalcomponentanalysis,thecontributionrateofeachprincipalcomponentcharacterwasusedasweight;Integratedfertilityindexineveryforesttypewascomputedbythewei
6、ghtedcalculationTheresultswereshownasfollows:withtheincreaseofthestandage,thesoilaciditypresentedincreasingtendencyinlarchplantationsofdifferentdevelopmentstages,thesoilbegantoacidify.Thecontentoftotalphosphorusandavailablekaliumpresenteddecreasingtendency,
7、andthecontentoforganicmatter,hydrolysablenitrogen,humicacidandhuminincreasedslightlyinnearmaturestand,buttotallydecreased.Comprehensiveevaluationofsoilfertilityshowedtheresults:naturalforest>youngstand>nearmaturestand>half2maturestand>matureforest,namely,wi
8、ththestandagesincreasing,soilfertilitybegantodecreaserapidlybecauseoftheslowlitterdecomposition.Itispro2posedthattheintensityofpartialcuttingshouldbeincreasedproperlyinordertoadjustcommunitystructure,i