## 3 Results  
The physical properties of mineral wool and lignite mats before and after cucumber cultivation are shown in Table 1. The new mineral wool mat has good physical properties typical of this substrate: density 61.13 kg m-3, porosity 97.70% and high content of readily available water. The air-water properties were favorable for greenhouse cucumber cultivation, and after cultivation (51 DAP), changes were observed in both physical properties and changes in organic matter content compared to the new substrate. There was a 58.7% increase in organic matter in mats after cucumber cultivation fed with standard MW/control EC medium and a 123% increase in MW/high EC mats fed with high EC medium compared to new mats (Table 1). Water content at a potential of \(-\)10 cm H\({}_{2}\)O increased by nearly 19% in MW/control EC mats and by 27.3% in MW/high EC mats. The plant-available water content also increased by an average of about 41%. These changes reduced the air content of the mat by more than 30% in the MW/control EC treatment and by 43% in the MW/high EC treatment, but it was still within the range of optimal levels for cucumber. The results indicate that mat water content increased toward the end of cultivation at the expense of air content. Higher EC did not cause much change compared to the control (Table 1). New lignite mat (New L) had high bulk density (378.15 kg m\({}^{-3}\)) and low porosity (77.07% vol). Its water holding capacity was low (41.32% vol) and it gave up water quickly, which promoted aeration of the mat and was reflected in the high air content regardless of the potential tested (Table 1 and Figure 1a-d). There was a 0.3% decrease in organic matter in mats after cucumber cultivation compared to new lignite mats. The lignite was also characterized by low plant-available water content, which was about 78.7% lower compared to the New MW mats. A beneficial feature of the amendments was the decrease in shrinkage of lignite during cultivation by 20.9% in the L/control EC treatment substrate and by 22.5% in the L/high EC treatment substrate compared to the New substrate (Table 1). Substrate parameters, measured in the mat extract, depended on substrate type and medium EC. The mineral wool substrate, when cucumbers were fed with standard nutrient solution (MW/control EC), had approximately 14% higher pH compared to the lignite substrate (L/control EC) and 5% higher pH for plants fertilized with high EC nutrient solution, regardless of mat height (Figure 2a,c,e). For ion concentration in the substrate, mineral wool and lignite, when fed capillary nutrient solution with higher EC (7 dS\(\cdot\)m\({}^{-1}\)), had higher EC at the top, middle, and bottom of the growing mat compared to mineral wool and lignite mats fed control nutrient solution (Figure 2b,d,f). The lignite mats in which the growing cucumber was fed with a high EC medium only had higher EC in the upper part compared to the mineral wool, where the cucumber was also fed with a higher EC medium (Figure 2b). In contrast, the middle and lower parts of the lignite mats at high EC of the nutrient solution had lower EC of the substrate compared to the EC of the mineral wool substrate also fed with high EC (Figure 2d,f). The lignite substrate where cucumbers were fed with high EC medium (L/high EC) had about 15% higher EC compared to mineral wool mats, where cucumbers were also fed with high EC medium (Figure 2b). At the middle height and bottom of the mat, the highest substrate EC values