TABLE CONTENTS

feeders. Pratylenchus dominanted in the coastal dune site vegetated with the grass, Elymus.
This research is continuing in 2008 with multivariate analysis to be done from a more
extensive dataset of nematode communities from plant communities and habitats, and soil
properties. These findings, in addition to providing lacking information of soil nematode
communities in subarctic environments, are also expected to provide a basis for long-term
monitoring of climate change impacts on soil food webs in an environment sensitive to
climate warming.
Community Structure and Vertical Distribution of Soil Nematodes in
Soybean Fields under Different Rotation Systems
Xu, Y. (1) X. Han (1), F. Pan (1,2), C. Li (1) & A. Liu (3)
Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin, P. R. China , 150081
(1); Graduate University of Chinese Academy of Sciences , Beijing ,100049 , P. R. China (2); Heilongjiang
Academy of Agricultural Sciences, Harbin, P. R. China , 150086 (3)
Soil nematodes are numerous, species-rich and widely distributed, and play essential roles in
soil organic matter decomposition, plant nutrient mineralization and nutrient circulation.
More and more scholars pay attention to the important function of soil nematodes in
agroecosystems. The study was conducted in a soybean field under continuous cropping for
15 years, alternate-year of wheat-soybean and wheat-maize-soybean rotation systems in
Hailun Agricultural Ecology Experimental Station ,CAS so as to elucidate the character of
nematode distribution, dynamic change and vertical distribution of nematode community.
In total, 8 order, 19 family and 43 genera nematodes were identified and 29 genera were
shared by the 3 soybean rotation systems; another 14 genera were different among soybean
rotation systems in that their distribution was affected by crop rotations and soil environment.
The total number of soil nematodes represents an increase-and-then-decrease trend in
continuous cropping for 15 years, while increasing continuously in alternate-year of wheatsoybean
and wheat-maize-soybean rotation at the soybean growth stages. The number of
Ditylenchus,Acrobeloides, Mesorhabditis, Protorhabditis, Panagrolaimus,Filenchus and
Coslenchus was different among soybean rotation systems.
The total number of soil nematodes displayed a gradual decrease trend with depth under each
rotation systems .The majority of nematodes were presented in the 0-30 cm soil layers. The
numbers of trophic groups in soybean field were higher than that in bare field. Predators-
Omnivores were less presented.
5 th International Congress of Nematology, 2008 273