关键词: 巨桉, 化感物质, 土壤

Abstract: In this paper allelochemicals were extracted by anhydrous ethanol from different soil layer of Eucalyptus plantation and native oak (Qucrcus acutissima) secondary forest in Hongyacounty, Sichuan.The extractions were identified by means of GC/MS (Agilent GC6890/MS5973).The conclusion shows that allelochemicals exist in Eucalyptus plantation positively, and the proportions of allelochemicals to the all extracted substances and compositions decrease with the increasing depth of soil.Allelochemicals from the layer of 0~5 cm are affected by many factors such as the inputs of aboveground, the distribution of fine roots, the activities of soil animals and microbes.There are far more allelochemicals in the Eucalyptus plantation than that of in the oak (Qucrcus acutissima) secondary forest and big differences between them with respect of compositions.How ever the proportions of allelochemicals to the all extracted substances of two kinds of forest are similar.The problem about impairing the disadvantages of Eucalyptus plantation management was discussed too.

Key words: Eucalyptus grandis, allelochemicals, soils