## 3 Results
### Starch Content and Yield  
Pre-planting treatments, in the form of treating tubers in an aqueous solution of the EM Farming microbiological preparation, did not significantly affect the starch content, but a positive tendency to increase the starch concentration in tubers was observed in both exposures to pre-planting treatments. However, in the case of starch yield, statistical calculations confirmed a significantly higher starch yield per area unit in the objects with replanting treatments in relation to the control object without seed potato dressing; both of these objects turned out to be homogeneous in terms of the value of this feature (Table 5).  
The factor that significantly determined both the starch content in the fresh weight of tubers and its yield per unit was cultivars. The highest starch content was found in the mid-late cultivar 'Kuras' and the medium-early 'Finezja' cultivar turned out to be homogeneous in terms of the value of this feature. In the second homogeneous group, due to starch content, were the cultivars 'Mondeo', 'Satina', 'Oberon', and 'Syrena'. In the third homogeneous group were the cultivars 'Denar', 'Bellarosa', 'Gwiazda', 'Ignacy', and 'Owacja', and the fourth homogeneous group included 'Vineta' and 'Jelly'. The relationships between cultivars changed slightly in the case of starch yield, where the highest value  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{1}{c}{**Experimental Factors**} & \multicolumn{1}{c}{**Content of DM (\%)**} & \multicolumn{1}{c}{**Yield of DM (\(\text{t.h.a}^{-1}\))**} \\ \hline \multirow{4}{*}{Pre-treatment treatments} & Control object & 20.2 a & 7.57 b \\  & Exposition I * & 20.4 a & 9.53 a \\  & Exposition II ** & 20.6 a & 9.28 a \\ \cline{2-4}  & HSDp005 & ns *** & 0.42 \\ \hline \multirow{8}{*}{Cultivars} & ‘Denar’ & 16.3 d & 7.98 b \\  & ‘Bellarosa’ & 18.0 c & 6.88 c \\  & ‘Gwiazda’ & 16.5 d & 7.35 b \\  & ‘Ignacy’ & 18.0 c & 8.79 b \\  & ‘Owacja’ & 17.7c & 6.56 c \\  & ‘Theta’ & 19.3 c & 7.86 b \\  & ‘Finezja’ & 23.9 b & 9.56 b \\  & ‘Oberon’ & 20.8 b & 8.26 b \\  & ‘Satina’ & 21.5 b & 10.33 a \\  & ‘Tajfun’ & 23.0 b & 9.88 b \\  & ‘Jelly’ & 20.2 b & 8.31 b \\  & ‘Mondeo’ & 22.1 b & 10.49a \\  & ‘Syrena’ & 21.0 b & 9.42 ab \\  & ‘Kuras’ & 28.0 a & 11.41 a \\ \cline{2-4}  & HSDp005 & 3.8 & 1.97 \\ \hline \multirow{4}{*}{Years} & 2017 & 20.1 a & 9.10 b \\  & 2018 & 20.7 a & 7.35 c \\ \cline{1-1}  & 2019 & 20.3 a & 9.89 a \\ \cline{1-1} \cline{2-4}  & HSDp005 & ns *** & 0.42 \\ \hline \multicolumn{4}{c}{Mean} & 20.4 \\ \hline \hline \end{tabular}  
* 10 min exposure; ** 15 min exposure, *** no significant differences at the level of p005, Letter indicators (a, b, c, etc.) next to the averages refer to the so-called homogeneous (statistically homogeneous) groups. The occurrence of the same letter indicator next to the means (at least one) means that there were no statistically significant differences at p005 between them.  
\end{table}
Table 4: Dry matter content and yield of tubers (mean 2017–2019).  
of this feature was obtained by the cultivars 'Kuras', 'Mondeo', 'Satina', 'Finezja', and 'Syrena'. The second homogeneous group included the cultivars 'Ignacy', 'Denar', 'Oberon', 'Gwiazda', 'Vineta', and 'Jelly'. The third homogeneous group, in terms of starch yield, were cultivars 'Bellarosa' and 'Owacja' (Table 5).  
last year resulted from the fact that the starch yield is the result of the starch content and the total yield of tubers, which was the highest in 2019. The yield of tubers depends on many factors, such as rainfall, sunlight, temperature, humidity, soil quality, fertilization, and the selection of cultivars.