Evaluation of the influence of composts made of sewage sludge, ash from power plant, and sawdust on floristic composition of plant communities in the plot experiment

Floristic studies were conducted in 2011 and 2012 on the soil reclaimed using composts made of sewage sludge with the addition of various amounts of ash from power plant and sawdust. The experiment was carried out in 2002 on devastated soilless formation in the area of “Jeziórko” sulfur mine. Strongly acidic soilless formation (weak loamy sand) was reclaimed using post-flotation lime for de-acidification at the dose of 300 t/ha and compost in various variants: municipal sewage sludge, sewage sludge (80%) + ash (20%), sewage sludge (70%) + ash (30%), and sewage sludge (70%) + sawdust (30%). The compost was added at following doses of dry weight: 90, 180, and 270 t/ha. In the prepared plots, each with the area of 15 m², a mixture of reclamation grasses was sown: Festuca pratensis –41.2%, Festuca rubra – 19.2%, Lolium perenne – 14.7%, Lolium multiflorum –12.4%, Dactylis glomerata – 6.5%, Trifolium pratense – 6%. The phyto-indication method was used to evaluate the impact of different ways of the soilless formation remediation on the habitat development. The assessment took into account following indicators: soil moisture, trophism, pH, organic matter content, resistance to salinity, and increased content of heavy metals. The largest number of species was found on plots where compost made of sewage sludge was used, while the smallest – on those reclaimed with sewage sludge compost with sawdust addition. In terms of habitat conditions, species preferring wet habitats typical of fresh soils, trophism of the subsoil corresponding to the abundant soils (eutrophic), neutral soil reaction, and subsoil with organic matter like in humus and mineral soils, dominated. The most favorable habitat conditions were found in plots reclaimed using sewage sludge compost.