Application of soil quality indexes for the habitat conditions variability assessment in the forestry rehabilitated former mining spoil banks

Abstract

According to Polish law, all former mining areas, whether for coal or other minerals should be rehabilitated. This paper analyses the possibility of using of indexes of Soil Trophy (ITGL) and Site Soil (SIG) to describe variability in the "Bełchatów" Brown Coal Mine dumping grounds for mining subsidence, which have been reclaimed for forestry. Research was conducted in four substrate variants forming the soil bedrock being created of: nutrient-rich, sandy clay Quaternary (NWL on the inside spoil bank) and clay silt (NZL on the outside spoil bank), as well as poorer Quaternary sandy (NWG on the inside spoil bank) and acidic Miocene sands after neutralisation by bog lime (NZG on the outside spoil bank). Based on the values calculated for the tested indicators, a site assessment was carried out according to the scale drawn up for "natural" conditions. It was confirmed that concerning these two indicators tested on the mine's spoil banks that the ITGL index reflected the soil variability better because the partial indicators valuation was based on the other soil properties and data transformation than the SIG. However, for a better description of the habitats which are forming in these conditions, it would be preferable to modify the partial indicators assessments described by these indexes based on the variability of post-mining soil properties.