EN
A pot experiment was conducted to determine the effect of contamination with the herbicide Faworyt 300 SL on the physicochemical properties of soil and microbial counts. Over the experimental period capillary water capacity of soil remained at a constant level of 60%. Variable factors were: herbicide dose (mm3 kg-1 of soil: 0, 0.12 — optimal, 1.20, 6, 12, 18 and 24), bentonite dose (0 and 2% in relation to soil dry matter) and time of analysis (day 25 and 50). The tested crop was spring rape, cv. Sponsor. Soil samples were taken on day 25 of the experiment and at the completion of the experimental period in order to determine the counts of particular microbial groups. Soil contamination with the herbicide Faworyt 300 SL contributed to disturbing the biological equilibrium of soil as well as to changes in its physicochemical properties. The counts of soil microorganisms were related to the degree of contamination.