EVALUATING OF WASTEWATER IRRIGATION IN LYSIMETER EXPERIMENT THROUGH ENERGY WILLOW YIELDS AND SOIL SODICITY, Carpathian Journal of Earth and Environmental Sciences, February 2018, Vol. 13, No. 1, p. 77 – 84; DOI:10.26471/cjees/2018/013/008

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In Hungary, alternative water resources utilization should take priority over the conventional irrigation water resources (surface and subsurface waters) in the future, similarly to the global trends because of the global warming and water scarcity. To preserve our most important renewable natural resource (soil), farmers and researchers are responsible for development of soil management practices and irrigation principles. Adaptation by farmers of this new, sustainable technologies soil degradation can be avoided, and the natural soil processes can be improved. Usage of different quality irrigation water was evaluated in our experiment measuring the variation of the soil exchangeable cations after one season of irrigations using wastewater in an energy willow plantation. The thermal water based wastewater, originated from an intensive catfish farm, was applied for micro-sprinkler irrigation in the Lysimeter Station of National Agricultural Research and Innovation Centre (NAIK), Research Department of Irrigation and Water Management (OVKI) in Szarvas, Hungary. According to our results the exchangeable sodium percentage (NaS%) increased significantly in all wastewater treatments with +1.16-4.4% after one year, and the sodium decreased significantly in the treatment with Körös River water irrigation with -0.26-1.1%. There were no significant changes in the NaS% when a diluted and improved (gypsum-added) wastewater was applied, and the soil’s sodium content did not increase above 200 mg/kg. In addition, the willow yields depended on the available irrigation water amount and there was no significant impact of the irrigation water quality on it. The highest biomass yields (4480.8±435.8 g/m²) were achieved in treatments with 60 mm water per two weeks. The accumulated sodium in the willow stem was less than 1% of the irrigation water sodium content, making the removal of this harmful element by willow harvest unsuitable. The results suggest that further wastewater irrigation usage might be sustainable with the diluted and improved quality water.