The effect of soil contamination with copper on soil biochemical properties and oat yields was assessed in a pot experiment. Copper was applied alone or in combination with other heavy metals. The study was conducted on samples of brown soil consisting of heavy loamy sand and brown soil developed from light silty clay. On days 28 and 56 of the experiment the following were determined: activity of dehydrogenases, urease, acid phosphatase and alkaline phosphatase in soil as well as oat yields.
Contamination of soil with copper, zinc, nickel, lead, cadmium and chromium in concentrations of 50 mg kg^-1 was found to have a negative influence on the activity of dehydrogenases, urease, acid phospha- tase, alkaline phosphatase and yield of oats. The soil enzymes can be arranged in terms of their sensitivity to heavy metals as follows: dehydrogenases > urease > alkaline phosphatase > acid phosphatase. Higher activity of dehydrogenases was determined in brown soil developed from heavy loamy sand, while urease, acid phosphatase and alkaline phosphatase were more active in brown soil formed from light silty clay. The contamination of copper with other heavy metals was inhibited in heavy loamy sand more than in light silty clay.