| At present, the ecological satety of Eucalyptus grandis is widely concerned. In recentyears, some scholars in foreign countries have studied Eucalyptus. It showed that chemicalactive components released by leaching, litter decomposing and root exudation can inhibitthe growth of plants and microorganism. Soil animal has stable relation to environmentwhere they inhabit, and their species composition and quantity distribution, and biomasscan reflect the quality of living environment. To know about toxicology further andassessment ecological risk of Eucalyptus grandis to soil animal, the acute toxicitiesexperiments which Eisenia foetida was exposed to different aqueous extract concentrationof Eucalyptus grandis leaf, litter and root were carried out. The results are as follows:1. The individuals and biomass of earthworms in Qucrcus acutissima were far morethan that of in Eucalyptus grandis plantation by investigating in the wild filed. In theEucalyptus grandis plantation there were more earthworms in the down layer compared tothe up layer and the weight of earthworms were also bigger in the down layer.2. Eucalyptus grandis leaf, litter and root aqueous extract had no obvious lethal effecton Eisenia foetida. There were differences during Eucalyptus grandis leaf, litter and rootaqueous extract, and the toxicity of leaf aqueous extract was the heaviest.3. In 60days the toxicity to earthworms was Eucalyptus grandis leaf aqueous extract＞root＞litter. The toxicity to earthworms intensified with increasing of aqueous extractconcentration. When leaf aqueous extract concentration was above 0.08g·ml-1 and root aqueous extract was higher than 0.1g·ml-1, the growth of earthworm was influenced. While,and the concentration of leaf aqueous extract, root aqueous extract and litter aqueousextract were below 0.02g·ml-1, 0.06g·ml-1, and 0.1g·ml-1 respectively, the biomass andphysiological indices of earthworm weren't influenced obviously.4. The chemical components of soil dipped into leaf aqueous extract, root aqueousextract and litter aqueous extract were much more than that of soil undipped in control, itshowed some chemicals were released into the environment by leaching, litterdecomposing and root exudation.5. Weight-gain of earthworm in Eucalyptus grandis plantation was lighter than that ofin Qucrcus acutissima during the 60-day. Cellulase activity of earthworm in Eucalyptusgrandis plantation was lower than that of in Qucrcus acutissima, but the activity of GSTand SOD were higher during the experiment. The result showed there was inhibitory effectof some organic chemicals on cellulase activity, but inductive effect of GST and SOD in acertain extent.6. The proportion of aellochemicals in the soil of 0～5cm layers of Eucalyptus grandisplantation and Qucrcus acutissima was no great differences, but the compositions ofaellochemicals made a great difference in results. There were much more aellochemicals inEucalyptus grandis plantation than in Qucrcus acutissima.7. The proportion and compositions of aellochemicals from all the extracted substancesdecreased with the increasing soil depth. The compositions of soil depth in 0～5cm and 10～20cm layerswere great different Eucalyptus grandis plantation. Although there was difference-between in50～10cm layer and 10～20cm layer, it was relatively less.
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