## 3 Results  
### Content and Yield of Dry Matter  
Pre-planting treatments, in the form of treating tubers with an aqueous solution of EM Farming, and years of research did not have a significant effect on the dry matter content of tubers. Only a tendency to increase the dry matter content of tubers was observed under the influence of exposure to EM Farming in relation to the control object. However, these impacts on the tubers caused a significant increase in the yield of dry matter per area unit, compared to the control object (Table 4).  
The genetic properties of the tested cultivars most strongly modified both the content and yield of tuber dry matter. The 'Kuras' cultivar was characterized by the highest content and yield of tuber dry matter. The second homogeneous group in terms of this feature included the following cultivars: 'Fineja', 'Oberon', 'Satina', 'Tajfun', 'Jelly', 'Mondee', and 'Syrena'. The third homogeneous group with a slightly lower content of tuber dry matter included 'Bellarosa', 'Ignacy', 'Ovation', and 'Vineta'. The lowest tuber dry weight was recorded in cultivars 'Denary' and 'Star'. The yield of dry matter was also significantly affected by the characteristics of the tested cultivars; the tested cultivars were grouped in terms of the amount of this feature in four homogeneous groups. The first group, with the highest dry matter yield, included 'Satina', 'Mondeeo', and 'Kuras'. Only one cultivar, 'Syrena', was included in the second homogeneous group. The third group, with lower tuber dry matter yield, included the following cultivars: 'Denar', 'Gwiazda', 'Ignacy', 'Vineta', 'Fineja', 'Oberon', 'Tajfun', and 'Jelly'. The lowest yield of dry matter per area  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Month**} & \multicolumn{3}{c}{**Rainfall (mm)**} & \multicolumn{3}{c}{**Air Temperature (‘C)**} & \multicolumn{3}{c}{**Hydrothermal Coefficient of**} \\  & **2017** & **2018** & **2019** & **2017** & **2018** & **2019** & **2017** & **2018** & **2019** \\ \hline April & 43.0 & 61.8 & 47.1 & 11.1 & 8.8 & 10.0 & 1.3 & 2.3 & 1.6 \\ May & 141.4 & 120.3 & 47.9 & 14.7 & 12.8 & 15.3 & 3.1 & 3.0 & 1.0 \\ June & 85.2 & 46.7 & 87.3 & 15.9 & 16.7 & 19.1 & 1.8 & 0.9 & 1.5 \\ July & 69.7 & 45.2 & 114.1 & 21.1 & 19.4 & 20.5 & 1.1 & 0.8 & 1.8 \\ August & 95.8 & 6.1 & 41.0 & 19.2 & 21.4 & 19.5 & 1.6 & 0.1 & 0.7 \\ September & 19.6 & 130.2 & 11.8 & 14.6 & 15.5 & 15.5 & 0.4 & 2.8 & 0.3 \\ \hline Total & 454.7 & 410.3 & 349.2 & - & - & - & - & - \\ \hline \end{tabular}  
* Coefficient was calculated according to the formula: \(\frac{k}{2\pi}\); Sovera [46]; where: P—the sum of the monthly precipitation in mm; \(\Sigma\)t—month total air temperature \(>0\)°C. Ranges of values of this index were classified as follows: extremely dry, k \(\leq\) 0.4; very dry, 0.4 \(<\) k \(\leq\) 0.7; dry, 0.7 \(<\) k \(\leq\) 1.0; rather dry, 1.0 \(<\) k \(\leq\) 1.3; optimal, 1.3 \(<\) k \(\leq\) 1.6; rather humid, 1.6 \(<\) k \(\leq\) 2.0; wet, 2.0 \(<\) k \(\leq\) 25; very humid, 2.5 \(\leq\) k \(\leq\) 3.0; extremely humid, 3.0 \(>\) k.  
\end{table}
Table 3: Rainfall, air temperature, and the hydrothermal coefficient of Sielianinov during the growing season of potatoes, according to the meteorological station in Uhnin, 2017–2019.  
unit was accumulated by cultivars of the fourth homogeneous group: 'Bellarosa' and 'Owacja' (Table 4).  
Meteorological conditions in the years of the study did not significantly affect the dry matter content, but they had a significant impact on the accumulation of dry matter yield. The highest value of this feature was recorded in 2019 and the lowest in 2018 (Table 4). The tested cultivars responded significantly to the conditions in the study years (Figure 1). The greatest difference in the dry matter content between the years of the study was noted in the case of cultivars 'Gwiazda' and 'Kuras'. In the case of the remaining cultivars, these differences turned out to be insignificant.