干旱区生态环境知识资源中心

The effects of organic amendments on nematode community structure were studied in an experimental site of the Atbasar oval plain in Central Kazakhstan with a continental climate. Nematode population densities and trophic composition were determined in soil under spring wheat cultivation in May, July and October 1995. The total number of individuals x m(-2) decreased significantly in all treatments, whereas the population’s diversity increased. Treatment responses were more consistent with the behavior of the trophic diversity index, with highest abundances found for bacterial and fungal feeding nematodes. Ectoparasitic Paratylenchidae were found to be the most abundant with 30 t ha(-1) organic amendment. The bacteriovore and fungivore population succession in the total nematode community resulted in food source availability which correlated with the seasonal and treatment rates playing an important role in the regulation of energy fluxes and internal nutrient cycling. The different approaches used in this study (functional groups, maturity index, trophic index, species composition, nematode community) demonstrate the importance and the need to increase our understanding in order to be able to assess the response of free living nematodes to soil biotic disturbances.