Open‐cast mining of lignite leads to considerable degradation of the natural environment, which then must be reclaimed. The aim of this study was to assess the transformation of Technosols in an area after lignite mining which had been under 40‐year cultivation of alfalfa with grass at various NPK fertilization rates. We hypothesized that 40‐year cultivation of plants caused morphological transformation of the parent material and resulted in differentiation of physical and chemical properties in the profile of the Technosols; fertilization had an added advantageous effect on their properties. The surface layer was transformed into an Ap‐horizon. Under alfalfa, with grass and NPK fertilization, Ap‐horizons demonstrated lower bulk density (BD) (7–11%) and particle density (PD) (1–2%), and higher total porosity (TP) (18–35%), drainable porosity (DP) (2–94%), field water capacity (FC) (11–21%), unavailable water (UW) (4–17%), soil organic carbon (SOC) (80–142%), total nitrogen (TN) (261–330%), available P (39–435%), available K (32–89%), cation exchange capacity (CEC) (25–43%), and soil acidity (Hext) (42–81%) compared to Cd‐horizons. Fertilized Technosols (1NPK, 2NPK), compared with control (0NPK), showed in the Ap‐horizon an increase in SOC (18–35%), TP (8–15%), DP (81–90%), FC (9–10%), P (110–285%), K (14–71%), and TN (0–18%), and a decrease in BD (4–7%). In contrast, fertilization had no effect on the UW, PD, soil inorganic carbon (SIC), CaCO3, available Mg, and pHKCl. The alfalfa and orchard grass played a key role in the reclamation and soil‐forming processes, while fertilization played a supporting role.