Spatial Differentiation of Topsoil Properties on Mine Spoil Heaps of the Moscow Coal Basin (Central Russian Forest Steppe)

Soil properties in the area of the former extraction of high-sulfur brown coals (north of the Central Russian Upland, Tula oblast) are characterized. We have analyzed three key areas, each representing one technogenic abandoned object: a conical unreclaimed heap, a leveled heap, and a remediated (revegetated) heap. A series of maps-temperature, pH, electrical conductivity (EC) of water extract, and contents of particle-size fractions, soil organic carbon, and chemical elements (Al, Ca, Fe, Mg, Mn, and S) in the topsoil (0-10 cm) layer-have been created for these areas. The conical heap is dominated by Spolic Technosols (Loamic), the dark topsoil of which is characterized by a strongly acid reaction (pH 3.2 +/- 0.5) and increased electrical conductivity (1.72 +/- 0.07 dS/m). In areas composed of burnt material, bleached and cooler (by 1 degrees C) Technosols (Loamic) occur; they have a lower acidity (by 0.7 pH units, p = 0.022) and electrolyte content (by 2.4 times, p = 0.022). Clay loamy soils of the leveled heap are represented by Spolic Technosols and Regosols. Plant-covered Regosols contain more particles <10 mu m in diameter and are characterized by higher pH, higher contents of potentially toxic (Al, Fe, Mn and S) elements and Ca (p < 0.001), and lower EC in comparison with bareground Regosols with insignificant differences in the total organic carbon content. The reaction of Anthrosols (Loamic, Transportic) of the revegetated heap is neutral due to the use of natural soil material; these soils are poorly differentiated according to the analyzed indicators, except for an increased S content and a reduced Ca content in soils on the steep slopes (p < 0.01), which is probably caused by the influence of the acid mine drainage.