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ID:32236311
大小:2.05 MB
页数:44页
时间:2019-02-02
《巨桉人工林凋落物、养分内循环与养分归还的动态变化》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、年转移总量大小依次为El>E2>E4>E3,即养分转移量与林分密度成正相关。叶的养分转移量比枝大数倍。(4)土壤有机质、全N、有效P、速效K含量在2006年开始出现下降,其中主要原因是由于人为干扰对森林立地有一定程度的影响,林地皆伐,地被物被去除,对样地的土壤养分和物理性质有较大的影响。本试验地洪雅的巨桉人工林已经达到成熟龄,可以进行采伐利用。为了尽可能补偿巨桉生长吸收的土壤养分,生态采伐季节应定在春夏季枝叶皮大量凋落过后,秋冬季为宜,这样能够通过凋落物部分归还巨桉吸收的林地养分。巨桉作为短轮伐期人工林,采伐利用的主要是
2、树干,将剩余的落皮、落枝、落叶和树根留在林地,则就有78.70"-"81.74%的养分贮量可以归还林地,对林地的地力消耗不会太大,这将有利于林地自我养分循环机制的形成,有利于维护林地养分平衡,实现巨桉人工林的可持续经营。综合来看,巨桉作为四川南部低山丘陵地区退耕还林工程和脆弱生态系统恢复树种,具有较好的社会、经济和生态效益。关键词:巨桉人工林;凋落物;养分归还量;土壤动物nAbstractLiRerismajormaterialpoolofforestorganicandthebaseofmaintainthesoiln
3、utrient,andthemajorcourseofthematerialcyclingandenergyflowin.forestecosystem.Itisveryimportantforthenutrienttoreturntosoilthroughlittertoremainthesustainableproductivityoftheforest.Now,theEucalyptusplantationisoneofmosttreespeciesplantedinsouthofourcountry.Itisvi
4、talsignificancetoplantandmanagetheEucalyptusplantationthroughresearchthecharacteristicoflittertothoroughlyunderstandthestructureandthefunctionoftheforestecosystem.FromJuly2004,theexperimentchoosetheEucalyptusgrandisplantationplantedin1997inHongYaSiChuanprovince,s
5、tudyonthelitterproduction,nutrientreturn,nutrientretranslocation,litterdecompositionandthesoilnutrientchangeinagrowthcycle,theresultshowed:(1)Theannualof2004.7.2005.6litterproductionforfourEucalyptusgrandisplantationwere8786keChm2、8112kg/hm2、5590kg/hm2、6011kg/hm2
6、.2005.7-2006.6litterproductionforfourEucalyptusgrandisplantationwerel0398kg/hm2,10258k#am2,5916kg/tma2,7012kg/hm2,respectively,itwasincrease16.2%,7.1%,5.5%,14.3%.TheannuallitterproductionWasconnectedwiththeforestdensity,leafproductionwasincreasedwiththeincreaseof
7、thestandingdensity,branchesandbarkshadnoremarkablerelationwiththedensity.ThecomponentsoflitterproductionWasleaf>branches>barks.Therewasapeakandvalleyinthewholeyear,highestinMayandlowestinJanuary.Thelitterproductionofseasonalvariationtendencyinsequenceofspring>sum
8、mer>autumn>winter.LeafmainlyfellinspringwhilebranchesandbarksfeIImaininsummer.(2)Theannualfivemacro.elementsreturntothesoilthroughlitterwere109.833kg.hm2,104.9
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