The interactive effect of reclamation scenario and vegetation types on physical parameters of soils developed on carboniferous mine spoil heap

Bulk density, porosity, and water retention capacity play a key role in limiting root growth and nutrient uptake in developed technogenic soils. Thus, the purpose of this study was to evaluate the impact of reclamation technologies and different vegetation types on vital physical soil properties formed from carboniferous materials. The case study was conducted on Sosnica hard coal post-mine spoil heaps (Upper Silesian Coal Basin of Southern Poland). Nine experimental combinations of reclamation technologies and vegetation types were tested. For vegetation types and basic physical soil parameters, 120 plots (10 x 10 m) were selected. The texture analysis was done on composite soil samples collected at two uppermost soil depths (0-10 and 10-20 cm). Intact structure samples were collected into 100cm(3) cylinders from the middle of each plot at both depths for bulk density (BD), porosity, capillary water capacity (CWC), and soil water storage (SWS). In the comparison of different reclamation scenarios, we noted that topsoiling increased BD, whereas CWC and porosity decreased. Spontaneous succession had the same effect on BD, porosity, and CWC as cultivation. Revegetation of the spoil heap with grasses and forbs resulted in lower BD and higher porosity and CWC in the top layer (0-10 cm), whereas woodland resulted in lower BD and higher porosity and CWC at lower depths (10-20 cm). The decreasing order of the SWS was grassland > forbland > woodland. Thus, forbs and grasses should be followed by tree planting, which is crucial to improving the hostile physical properties of the Carboniferous postmine soils.