Calculation nitrogen and sodium budget from lysimeter-grown shortrotation willow coppice experiment

Abstract

Alternative water resources utilization should take priority over the conventional irrigation water resources (surface and subsurface waters) in the future in Hungary as well, similarly to the global trends because of the climate change impacts. However because of the environmental risks (e.g. nitrate leaching and soil salinization) the reuse of the wastewater require sustainable practices hence the farmers and researchers are responsible for development soil management practices and irrigation principles. Aim of our study was to determine the impact of a wastewater originated from an African intensive catfish farm on the nitrogen budget of the soil-water-plant system in order to evaluate the nitrogen substitution effect and the risk of the nitrate leaching. On the other hand, the aim of the study was to calculate also sodium budget to assess the risk of the sodicity regard to the high sodium concentration of the wastewater. The experiment was conducted at the National Agricultural Research and Innovation Centre (NAIK), Research Institute of Irrigation and Water Management (OVKI) in Szarvas, Hungary. The experiment was set up in the NAIK ÖVKI Lysimeter Station in 2014 with energy willow. During the study (between 03.07.2015 and 21.04.2017) irrigation water quality, rainwater quality, willow N and Na uptake by stems and N and Na leaching was measured. Nitrogen and sodium budget were calculated for two years (2015, 2016) from these data. According to our results the wastewater had high nitrogen content what was able to increase the nitrogen amount in the examined budget however without supplementary fertilizer it could not able to balance the budget only just at W60 treatment (irrigation with wastewater: N concentration 22,7 mg/l). The wastewater had high environmental risk as soil sodicity according to results of the sodium budget.