Conventional agricultural practices need to be modified in order to adapt to changing environmental factors because of the increasing frequency of extreme hydrological events. The development of new irrigation management practices, the use of water and energy-saving methods and the reutilization of wastewater (agricultural effluents, treated wastewater etc.) could be important elements in this adaptation.

The aim of our research was to determine the environmental risk of irrigation of an effluent from an intensive fish farm due to its impact on the chemical composition of groundwater, in particular nitrate pollution. In the lysimeter experiment, high-quality surface water (Körös Bikazugi’s oxbow lake) as control irrigation water was used for the irrigation of energy willow between 2015 and 2017. At the end of the experiment, values of the leachate parameters were compared with the values measured in the non-irrigated treatment also. We concluded that the quality and quantity of irrigation waters influenced the chemical composition of the leachate generated in the lysimeter experiment: mainly the total dissolved salt content (TDS) and the nitrate-N concentration. Wastewater proved to increase sodium and nitrate concentrations in the leachate compared to the values in surface water treatments however did not exceed the nitrate-N concentration measured in the non-irrigated treatment which were the highest in both experimental years (2016: 75.8 mg l-1, 2017: 49.7 mg l-1). The high sodium concentrations (47–133 mg l-1) of leachate in wastewater treatments (compared with the surface water irrigated and non-irrigated (31–58 mg l-1) treatments) were occurred due to the origin of wastewater.

Keywords: irrigation water quality, nitrate leaching, salinity