## 1 Introduction
There have been numerous studies [11; 12] that investigated the negative impact of waterlogging on the yield of maize, especially during the early seedling stage to the tasselling stage [13], with yield reductions of 25-30% [14]. Given the increasing evidence of climate change in terms of the lack of or excessive rainfall, as well as the poor distribution and high air temperatures, substantial increases in maize yields will require developing cultivars with greater water use efficiency, which is a trait that has not been a priority for breeders in the past [15]. Water (irrigation) and nitrogen (fertilization) have long been recognized as two major limiting factors for maize production. Following that, the results of numerous studies indicate a decrease in maize yield due to a water deficit [16; 17; 18; 19; 20] and an increase in maize yield with an increase in the N rate [21; 22; 23]. The yield reduction of maize grain is mostly proportional to the severity of the drought stress, but it should be noted that research on the impact of irrigation on maize yield gives different results and conclusions. For example, some study results indicate that the highest maize GYs are achieved after treatments with the highest net irrigation [24; 25; 26; 27], while some of the studies [28; 29; 30] have confirmed that increasing the amount of water does not directly equate to higher yield results. This is supported by the results of a meta-analysis conducted by [PERSON] et al. [31]. These authors claimed that maize yield increased linearly with increasing water input with 3% of the variation in yield when the total water input was less than 314 mm, while further water input decreased maize yield with 3% of the variation. As for N fertilization, the same authors claimed that maize yield increases linearly with increasing N input with 12% of the variation in GY when the total N input was less than 250 kg ha\({}^{-1}\), while further N input did not affect the maize yield. In addition to GY, the water deficit also has a negative effect on the quality of maize in terms of the grains' chemical composition. Several studies confirmed that crude oil, starch, and ash yield are considerably decreaseddue to water deficit [32; 33; 34; 35; 36]. This, of course, is of great importance when maize is grown for the food industry and animal feed production, where high grain quality is expected. Previous studies emphasized the importance of the interaction between growing systems (irrigation and fertilization), weather conditions, and soil properties for soil water and nutrient availability, as well as crop yield potential [37; 38; 39; 40; 41]. An interesting observation was made by [PERSON] et al. [20]. The authors claimed that the increasing N rate from 200 to 300 kg N ha\({}^{-1}\) resulted in increased maize biomass and GY under a 75-80% FC irrigation treatment, while it had no impact on those under the 45-50% and 60-65% FC treatments. Prior research [42] suggests that there is an optimal nitrogen application amount that maximizes the effectiveness of irrigation water on increasing GY above rainfed yields. The authors claimed that the optimal N level for maximum productivity varied not only between the irrigation levels but also exhibited interannual variability for the same irrigation level, indicating that these variables are impacted by the climatic conditions. [PERSON] and [PERSON] [43] and [PERSON] et al. [44] claimed that excessive application of N fertilizer has negative effects on crops, greatly reduces N use efficiency (NUE), and causes significant nitrate leaching losses and contamination of groundwater. The main source of nitrate contamination that is associated with groundwater is crop production, i.e., N fertilization [45] due to the low N fertilization efficiency [46]. In the European Union (UN), the Nitrate Directive (1991, 91/676/EEC) is the main regulation for reducing the environmental impacts of N fertilizer and for increasing nitrogen use efficiency. According to the regulation, the N target in groundwater is 50 mg NO\({}_{3}\).