Abstract: In this paper, meso-micro soil fauna were extracted and collected by Baermann’s and Tullgren’s method, and their distribution pattern in theEucalyptus grandis plantation of Hongya County, Sichuan Province was studied. A total of 13550 specimens were collected, belonging to 6 phyla, 13 classes, and 26 orders. Acarina, Nematoda, Collembola were the dominant groups, and Enchytraeidae was the frequent one. The group and individual numbers of meso-micro soil fauna varied with seasons, being the maximum in autumn or winter, fewer in summer, and the minimum in spring. The density of meso-micro soil fauna in soil profile decreased rapidly with increasing soil depth, but a converse distribution was observed from time to time in 5～10 cm and 10～15 cm soil layers. The meso-micro soil fauna collected by Baermann’s and Tullgren’s method had a density of 3.333×10³～2.533×10⁵ ind·m^-2 and 1.670×10²～2.393×10⁵ ind·m^-2, respectively, and the decreasing rate of the density with the increase of soil depth was higher for those collected by Tullgren’s method. The density-group index of meso-micro soil fauna in the E. grandis plantation was the lowest in spring, but the highest in autumn or summer. There were no significant differences in the density of meso-micro soil fauna and in the density-group index between E. grandis plantation and Quercus acutissima secondary forest.

Key words: Leymus chinensis, Clone, Generation of vegetative propagation, Ramet, Bud bank, Module, Age structure