Short-term effect of mefenacet,an acetanilide herbicide,on soil microbial
communities in paddy soil was studied.The Biolog
method(a kind of colour development assay) was used to determine substrate utilization potential of microbial(
communities) for assessment of biological communities.The results show that
functional diversity of the microbial communities(decreased,) and capability of the microbes of(utilizing) substrate of simple carbon sources reduced in mefenacet-polluted soils(compared) with those in non-polluted soil.However,this effect was transient,and functional diversity of the microbial(communities) in mefenacet-polluted soils came back at the end of the experiment.Supplementation of (strain) Y1 had a positive(effect) on metabolic potential of the soil microbial(communities.) A kinetic method was presented for characterizing the (physiological) state of microorganisms capable of carrying out specific metabolic function in paddy soils.Test well dye reduction was non-linear in microplates inoculated with duration of the incubation,and the color development curve was generally sigmoidal in shape.Test well OD values over time suggested a kinetic model based on the density-dependent logistic growth equation.The kinetic parameters generated by the model can be used as(surrogates) for single-time-point data in constructing (carbon) source(utilization) patterns.And a and x_0 were more sensitive to indicate the effects of mefenacet and strain Y1 on functional diversity of the microbial communities.Shannon index(H) was more sensitive than the index of microbial community richness(S) to show the(microbiological) change in contaminated environment.