Acidification of soils is an important process degrading the natural environment. It undergoes various natural processes as well as human activities. Therefore, the objective of the study was to evaluate effects of differentiated nitrogen fertilization and simulated acid rain on
enzymatic activity of some soils of a microplot system. Soil samples were analysed for dehydrogenase, cellulase and proteolytic acitivites. The results indicated that increasing nitrogen rates stimulated the activity of the enzymes under study. Introduction of acid rain did not cause a decrease of enzymatic activity of soils.