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BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS ABUNDANCE OF RHABDITID NEMATODES IN AGRICULTURAL SOIL OF KHORRAMABAD, IRAN 219
Vafa, Saeedizadeh and Bostani
with slightly alkaline property (soil pH more than 7). The
average frequency of Rhabditid nematodes in the soil
with pH more than 8 was numerically higher than that
of 7-8. However, this superiority was not statistically
signi cant. In general, results of this study showed that
the nematode populations signi cantly decreased at the
soil pH less than 7.
As described by Garbeva et al. (2004) and Šalamún
et al. (2014), changes in soil pH could have led to direct
and indirect effects on the nematode community. Like-
wise, results of this study revealed that the abundance of
Rhabditid nematodes decreased at lower pH of the soil.
Korthals et al. (1996), believe that a lower pH enhances
the toxicity of heavy-metals through increase of their
adsorption to the soil.
Korthals et al. (1996), have shown that nematodes
exchange several ions through their cuticle in order to
regulate their osmotic pressure. It has been suggested that
soil acidi cation can lead to increasing ion concentra-
tions in the soil pore water to such an extent that nema-
todes might experience problems in regulating their water
status. They also stated that, soil pH indirectly affected the
nematode community by in uencing food availability, by
interfering with the competitive interactions between spe-
cies, or by affecting the abiotic environment.
In conclusion, results of the present study indicated that
crop type as well as soil pH could affect Rhabditid nema-
todes communities. The outcome is important in terms of
biological control of soil pests which leads to preservation
of agro-ecosystem through less use of chemical pesticides
and achievement of a sustainable agriculture.
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