## 2 Materials and Methods
### Conditions for Conducting Field Experiments  
Certified seeds of selected varieties of winter wheat were sown in the following years of this study: 10 October 2020 and 09 October 2021, at the rate of 300 units-m\({}^{-2}\). The area of each experimental plot averaged 1 ha (class III soils).  
Soil pH and content of basic chemical components before fertilization are shown in Table 2. One variant of nitrogen fertilization of 60 kg N\(\cdot\)ha\({}^{-1}\) (20 kg N\(\cdot\)ha\({}^{-1}\) + 40 kg N\(\cdot\)ha\({}^{-1}\)) was applied in the experiments. Mineral nitrogen fertilization (ammonium nitrate 34% N Pulan) of winter wheat was carried out twice at stage BBCH 25-26 (beginning of spring vegetation) and stage BBCH 32-34 (stalk shooting). The harvesting of wheat grain in subsequent study years was performed at full harvest maturity (13 August 2021 and 27 July 2022).  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & **2020** & **2021** & **2022** \\ \hline pH & 6.60 & 6.59 & 6.31 \\ \hline Nitrogen (kg N\({}_{\text{min}}\) in layer 0–60 cm\(\cdot\)ha\({}^{-1}\) of soil) & 51.1 & 52.3 & 50.7 \\ \hline Phosphorus (mg P\({}_{2}\)O\({}_{5}\)’100 g soil\({}^{-1}\)) & 18.90 & 19.90 & 21.20 \\ \hline Potassium (mg K\({}_{2}\)O\(\cdot\)100 g soil\({}^{-1}\)) & 24.60 & 24.90 & 25.10 \\ \hline Magnesium (mg Mg\(\cdot\)100 g soil\({}^{-1}\)) & 7.50 & 6.80 & 6.10 \\ \hline Humans content (\%) & 1.30 & 1.25 & 1.35 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Soil pH and content of basic chemical components before fertilization in the analyzed years of the study.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & & & & \multicolumn{3}{c}{**Chemical Composition**} \\ \cline{4-7}
**Farm** & **Year of** **Research** & **Weheat** **Cultivar** & **pH** & \begin{tabular}{c} **Nitrogen** \\ **(kg N\({}_{\text{min}}\) in Layer** \\ **0–60 cm\(\cdot\)ha\({}^{-1}\)** \\ **of Soil)** \\ \end{tabular} & \begin{tabular}{c} **Phosphorus** \\ **(mg P\({}_{2}\)O\({}_{5}\):** \\ **100 g Soil\({}^{-1}\))** \\ \end{tabular} & \
\begin{tabular}{c} **Potassium** \\ **(mg K\({}_{2}\)O:** \\ **100 g Soil\({}^{-1}\))** \\ \end{tabular} &
\begin{tabular}{c} **Magnesium** \\ **(mg Mg\({}_{1}\)Og** \\ **100 g Soil\({}^{-1}\))** \\ \end{tabular} \\ \hline \multirow{2}{*}{A} & I & Rockefeller & 6.60 & 41.7 & 17.60 & 11.86 & 8.73 \\ \cline{2-7}  & II & Lawina & 6.45 & 55.6 & 11.68 & 19.06 & 5.45 \\ \hline \multirow{2}{*}{B} & I & Elxer & 6.95 & 58.5 & 41.10 & 17.61 & 6.62 \\ \cline{2-7}  & II & Elxer & 7.23 & 51.3 & 15.02 & 17.04 & 11.49 \\ \hline \multirow{2}{*}{C} & I & Lawina & 6.78 & 69.1 & 13.48 & 18.90 & 12.07 \\ \cline{2-7}  & II & Rockefeller & 6.85 & 82.4 & 13.44 & 10.39 & 12.24 \\ \hline \multirow{3}{*}{D} & I & Rockefeller & 6.67 & 157.8 & 11.26 & 10.82 & 9.27 \\ \cline{2-7}  & I & Gimantis & 6.60 & 162.7 & 11.56 & 10.33 & 9.35 \\ \cline{2-7}  & II & Elxer & 6.65 & 92.4 & 14.88 & 9.83 & 5.94 \\ \cline{2-7}  & II & Gimantis & 6.40 & 97.1 & 18.26 & 21.01 & 4.89 \\ \hline \multirow{4}{*}{E} & I & Elxer & 6.63 & 39.2 & 11.27 & 19.02 & 8.54 \\ \cline{2-7}  & I & Lawina & 6.48 & 207.2 & 12.75 & 14.38 & 5.27 \\ \cline{1-1} \cline{2-7}  & I & Rockefeller & 6.42 & 124.2 & 39.48 & 23.66 & 5.64 \\ \cline{1-1} \cline{2-7}  & II & Gimantis & 6.36 & 106.6 & 13.81 & 16.82 & 5.06 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Soil pH and content of basic chemical components before mineral fertilization on farms in field experiments.