3.4. Phytotests with meadow vegetation
Based on the data gathered throughout phytotests with mesic and dry meadow, the results showed a promising opportunity for implementing the tested soil substitutes from stage III as trials at the coal mine affected areas such as Janina Mine waste heap in Libiąż (Figures 4 and 5).
FIGURE 4
FIGURE 5
These plants were less sensitive to the harmful effects induced by salinity which in case of white mustard significantly limited and even hampered the first sproutings as well as its further growth. Additionally, both the mesic and dry meadow plants belong to the dicotyledonous plants which may develop a dynamic green biomass production, intensifying the rhizosphere activity and finally increasing carbon dioxide assimilation. The number of species for the mesic meadow (Figure 5a) varies between 5 (for A1, B1, C2, C3, and D5) through 6 (for A2, B2, B3, C1 and D2) to finally the highest number of species, i.e. 7 for D1, which indicates biodiversity of development ecosystems. The vegetation cover, as a proof of ability to growth in new environments varied significantly, from 40 to 90%.
The number of species for dry meadow (Figure 5b) fluctuated also in a large range, from 4 (A2, D3) through 5 (A1, B3, C1, C3, D1, D2) to 6 (A3, B2, C2), reaching even 8 for B1 (Figure 6). The coverage was much more disparate: from 30 to 90%, whereas 30% applied to only a single case (D2).
PCA (Table 7) was performed for evaluating the influence of the physical and chemical parameters of the soil substitutes on the meadow vegetation development. The first ordination axis of the PCA model (axis 1) accounts for 65.2 % of the total variation of vegetation. This axis has a positive correlation with content of OM (0.60) and a negative correlation with the concentration of P (-0.45). The cover of mesic meadow species (Flo_Mea, %) and dry meadow species (Dry_Mea, %) has a negative correlation with this axis. The second axis (axis 2) explains 19.5 % of response variables variation and shows a gradient in soil pH values. This axis has a positive correlation with the cover of mesic meadow species and a negative correlation with dry meadow species cover. The graphical illustration of the PCA analysis was presented in Figure 6.
TABLE 7 Parameters of control soils used in germination tests