The aim of the study was to evaluate the impact of plant coverage of the soil on the amount of water moving through the soil profile and the concentration of N-NO₃, as well as the volume of load components taken out from the soil. The lysimeters were cover by the following plants: cocksfoot (Dactylis glomerata L.) – non-fertilized, cocksfoot (Dactylis glomerata L.) and perennial ryegrass (Lolium perenne L.) – fertilized with doses 20 kg P, 50 kg K i 120 kg N·ha^-1, and red clover (Trifolium pratense L.) - fertilized by 20 kg P and 50 kg K·ha^-1. The study was conducted in 2009–2011 in Nowosielce, Podkarpackie province. Two sub-periods were distinguished in the vegetation season. The first period included growth of plants in the first regrowth, and the second in the second one. During the experimental period the biggest amount of water moved through the soil profile in the control object, and the least in the object with the red clover. The greatest concentration of NO₃-N was found in water seepage in the object with red clover. The largest load of NO₃-N was stated in this object as well. It was two times bigger than the load in the control object, by 20% bigger than in the object with perennial ryegrass and by 8% bigger than in the object with fertilized cocksfoot.