Verifying the Utility of Black Locust (Robinia pseudoacaciaL.) in the Reclamation of a Lignite Combustion Waste Disposal Site in Central European Conditions

N-fixing tree species, such as black locust, have achieved very promising results in the reclamation of technosols, especially those at combustion waste disposal sites, which have extremely poor nutrients and adverse physicochemical parameters. This paper presents an assessment of the survival rates, growth parameters, and quality and vitality of and nutrient supply (NPK) to black locust (Robinia pseudoacaciaL.) specimens that were experimentally planted on a lignite combustion waste disposal site. The black locust seedlings were introduced directly into the combustion waste using two variants of NPK (7% N, 5.5% P2O5, and 9% K2O) fertilisation, at doses of 250 and 500 kg ha(-1), and in control plots with no mineral fertilisation. No significant impacts of the applied mineral fertilisation were found on the soil properties, growth parameters, or nutrient supplies to the trees. Black locust introduced to the landfill after three years of revegetation was characterised by a very high survival rate of 95%-100%, as well as good growth parameters (height and diameter at the root collar). Nutrient supply was determined on the basis of the chemical composition of the leaves, which indicated an adequate supply of nitrogen, similar to levels found under natural conditions. In the case of K and P, the supply levels were lower than optimal when compared with data from the literature. However, at this initial stage of tree development on the combustion waste disposal site, nutrient supply is similar on all variants and is not a critical factor for successful black locust introduction. We suggest using growth parameters, survival, and vitality of trees as decisive factors for the reclamation of combustion waste landfill sites strategy. All these factors confirmed the usefulness of black locust to the reclamation of combustion waste disposal sites.