Forestry Reforestation vs. Spontaneous Revegetation – Soil Changes in Coal Mining Spoil Heaps Across Bulgaria

The paper presents results of an investigation of forestry reclamation and spontaneous revegetation on Technogenic soils (Technosols) formed as a result of coal mining activities. The soils are located in “Мaksim taban" deposit site, Pernik, Bulgaria. Soil samples were taken at twenty-two profiles at representative plots under spontaneous revegetation - herbaceous plant cover (eleven profiles) and under forestry reclamation - black pine (Pinus nigra Arn.) (eleven profiles) at a depth of 0-100 cm. The changes in physicochemical properties were investigated under different vegetation and at different soil depths. The results reveal that most soil characteristics, such as bulk density, total porosity, the content of sand, silt, plant available water coefficient, pH, total organic carbon, total Kjeldahl nitrogen and available potassium are statistically significantly different under different vegetation. There are strong positive or negative correlations among soil characteristics and with soil depth.