EN
In incubation experiments the microbiological equilibrium of two sandy soils was unsettled using captan in a dose which considerably influenced fungi. The reduction of the fungal community contributed to an intensive multiplication of the bacteria detectable by the cultural method, particularly of the number of their eutrophic forms. However, the changes in the discussed ecotrophic group of bacteria were not accompanied by an increase in the total number of the soil bacteria community detectable with the help of the microscope and consisted for the most part from oligotrophic bacteria. Moreover, there was a continous declining tendency and overall microbial activity of the soil was in most instances reduced. All the described effects were intensified by the addition of fresh organic matter.