Experiments were carried out on about 10 thousand hectares catchment basin situated on the Kościan Plain (approximately 50 km from Poznań). In general, light textured Udalfs with favour able water infiltration conditions are found in the higher parts of the area. These are soils typical for the Polish Lowland. Aquolls are found in the lower parts of the catchment basin. The average annual precipitation in this region is at the level of 604 mm. The average period of plant growth lasts for 225 days. Within the catchment basin, there are numerous shelterbelts of varying age and species composition. Soil samples for the analysis of chemical composition of soil solution and samples of ground water from shelterbelt area were collected in spring and autumn. Soil samples were collected from soil profiles (from each horizon to the depth of 150 cm). For comparison, samples of soil and water were also collected from the adjacent cultivated field. It was found that the soil solution and ground water under shelterbelts (irrespective of their age and species composition as well as differences in soil cover) were clearly poorer in nitrogen concentration (especially, nitrates) in comparison with the adjacent cultivated field. On the basis of the obtained results it can be said that, already after one year after shelterbelt planting on cultivated field, evident changes take place in the soil environment of the cultivated field, which confine migration of mineral nitrogen to the catchment basin. This shows that shelterbelts planted in catchment basins with intensive farming practices can rapidly give positive results as evidenced in the reported study by reduced quantities of nitrates leached from soils into ground and surface waters.