The influence of three ciliates on soil microbial biomass and soil available N and P content
三种纤毛虫对土壤微生物量和有效氮磷含量的影响

The effects of tree ciliates on soil microbial biomass, N and P transformation was studied through soil incubation experiment. The results showed that inoculation of the isolates of Colopodia sp., Oxytricna sp. and Australothrix sp.,largely reduced soil microbial biomass carbon.It was evident that there was a negative interaction between the tested protozoa and soil microorganisms.Available P content was significantly reduced due to introducing the isolate of Australothrix sp.. However,it was not significantly affected by inoculating the isolates of Colopodia sp. and Oxytricna sp. during initial 15 d incubation,but significantly lower at late incubation.The three protozoa,in particular the Australothrix sp., decreased N mineralization and nitrate content,but increased ammonium content.It indicated that the tested protozoa inhibited nitrification,but stimulated ammonification.