The influence of long-term land reclamation on the microbiological properties of post-mining soils

The aim of the study was to analyse the enzymatic activity of dehydrogenases, urease, alkaline phosphatase and proteases in post-mining soils. Moreover determined the count of heterotrophic bacteria, moulds, actinobacteria and bacteria of the Azotobacter sp. genus. The research was conducted between 2015 and 2017 in experimental areas of the Patnow dump, which belongs to the Department of Soil Science and Land Reclamation, Poznan University of Life Sciences. Soil samples for analysis were collected at depths of 0-30 cm and 30-60 cm. The first factor under analysis was two simplified crop rotation systems, i.e. a rapeseed and cereal system (alternating cultivation of wheat and winter rapeseed) and a forage and cereal system (the cultivation of alfalfa with grasses for four years followed by the growing of winter wheat for the next two years). The second factor under analysis was three sub-blocks with increasing mineral fertilisation levels: 0NPK, 1NPK and 2NPK. The research results were analysed by means of one-way analysis of variance. Homogeneous groups were identified with the Tukey test at a significance level alpha=0.05. The Statistica 13.1 program was used for statistical calculations. The post-mining soils were classified as Calcaric Regosols (IUSS Working Group WRB, 2015). The microbiological activity of the soils exhibited high variability both in the growing season and in the subsequent years of the research. The forage and cereal crop rotation system had better effect on the soil microbiological and biochemical activity than the other system. Therefore, feed and cereal crop rotation is recommended for the reclamation of soils in internal post-mining dumps.