The role of growing grasses in reduction of negative effects of acidic depositions on soils was studied in a deforested site fully exposed to air pollution. Acidophilous grasses (Calamagrostis arundinacea and C. villosa), which spread on clear-cut areas, were planted in blocks of forest soil inserted in plastic boxes modified to lysimeters. The examination of the effects of wet bulk depositions of nitrogen, SO42- and pH of rain water revealed that mainly nitrogen influenced considerably the features of soil percolates. Increasing deposition of nitrogen resulted in increasing acidity and conductivity of percolates and in greater amounts of leached nitrogen (above all nitrates) and basic cations (especially Ca2+). These tendencies were more pronounccd in variants without grasses and with the application of additional nitrogen. Thus the grass stand formation on deforested areas has a positive effect on the reduction of nutrient losses from the forest soil affected by acidic depositions.