The purpose of this study is to determine the influence of nitrogen fertilization and irrigation on the total count of aerobic mesophilic microorganisms, moulds and yeasts in the soil. The experiment was conducted in three variants and samples were taken as follows: from irrigated and fertilized furrow; from irrigated non-fertilized furrow and from furrow without irrigation and fertilization. For determination of total number of mesophilic aerobic microorganisms, moulds and yeasts the samples were diluted and cultivated on medium sheets coated with culture medium according to the requirements of the microorganisms. Data analysis shows that fertilization has the strongest multiplication effect on the number of aerobic mesophilic microorganisms in soil (their 6 6 number increases from 10.522 x 10 to 12.8 x 10 cfu/g), whereas the irrigation does not have any statistically significant impact. The multiplication of moulds 5 and yeasts in this trial is stimulated mainly by the increased humidity. When irrigation is applied the number of moulds and yeasts increases from 1.158 x 10 to 5 1.407 x 10 cfu/g, while fertilization does not affect their quantity in a statistically significant way.