Abstract: In this paper,an investigation on the species richness and abundance of soil nematodes in farmland,natural secondary forest,shelter forest and green space was made in Changchun City in July and September,2003.Soil nematodes were extracted with Baermann extractor,and identified to the genus level with the aid of microscope.A total of 7 273 soil nematode individuals were captured,and fell into 2 classes,7 orders,20 families,and 27 genera.Aphelenchus,Tylenchus and Pratylenchus were the dominant genera,which accounted for 61.58% of total individuals.Land use type had a significant effect on the community structure of soil nematodes,and aboveground litter removal and cultivation activity were the main factors affecting soil nematodes community structure.Aboveground litter removal considerably decreased soil nematodes individual density and community diversity,while cultivation activity changed the vertical distribution of soil nematodes individual density in the soil profile.Aboveground vegetation structure and landscape pattern appeared to have little effect on the ecological structure of soil nematodes community.

Key words: Salt stress, Transgenic wheat, Respiration pathway