Impact of nitrogen fertilizers on groundwater quality-some examples from Czechoslovakia

Abstract

In many regions of Europe with intensive agricultural production, a statistical relationship has been demonstrated between the amount of nitrogen fertilizer applied and the nitrate contents in groundwater. The movement of nitrogen in the hydrogeological system is controlled by natural cyclic processes, anthropogenic influences and random events. A research program into the effects of farming activities on the groundwater quality in Czechoslovakia is under way on experimental fields (20–30 ha) and, simultaneously, in shallow aquifers on a regional scale (3000 km 2). The importance of the soil organic matter's stability for maintenance of the groundwater quality is emphasized. Research based on the nitrogen balance and the balance of organic carbon have shown, that the restoration of a soil-groundwater system is a complicated process which usually requires changes in the extent and intensity of agricultural activities and consistent attention to natural conditions. Regional investigation of agriculture's impact on shallow aquifers in the fluvial deposits of the Elbe River in Bohemia has proved the hydrochemical instability and vertical hydrochemical heterogeneity of these aquifers. The research results are used to make national and regional agro-groundwater managerial schemes more precise.