Abstract: To examine the effects of different habitats on the nematode communities in rhizosphere soil, an investigation was made on the ecological characteristics of nematode communities in rhizosphere soils of coniferous-broadleaved mixed forest, coniferous forest, and Cryptomeria fortunei nursery in Northern Fujian from September 2003 to August 2004. A total of 56 327 nematode individuals belonging to 2 classes, 4 orders, 12 families and 35 genera were collected. The numbers of nematodes varied significantly (P<0.01) with habitats, being in the sequence of coniferous-broadleaved mixed forest>coniferous forest>C. fortunei nursery, and decreased in the order of spring>winter>autumn>summer. There was a significant difference in the vertical distribution of nematode functional groups in the soil profile, i.e., 0-5 cm>5-10 cm>10-20 cm, but two dominant groups of herbivores had a distribution of 0-5 cm>10-20 cm>5-10 cm. An obvious spatial heterogeneity in the root biomass and soil physical and chemical characters (e.g., moisture content, porosity, and contents of organic matter, total and available N, and available P) was observed in the three habitats, and the numbers of nematodes had a significant positive correlation with it. It was suggested that the community structure and its dynamic changes of soil nematodes could be used as an important biological indicator for soil ecosystem health and for the diseases management of C. fortunei.

Key words: Water deficit, Supplemental irrigation, Winter wheat, N uptake, N residue