شیمی خاک آلوده شده با گوگرد، لایه فراش شیرابه گوگرد استخراج شده از معدن با روش قبلی در شکل های گوناگون زباله در یک آزمایش کنترل شده Chemistry of Sulfur-Contaminated Soil Substrate from a Former Frasch Extraction Method Sulfur Mine Leachate with Various Forms of Litter in a Controlled Experiment

1 Introduction Sulfur is a common element in the environment and is indispensable for plants (Marschner 2011). However, excessive concentrations of sulfur have a negative impact on plants, damaging their root system, foliage, thinning of crowns, deformation of trees, and reduced growth (Tomlinson 1983). The effect of high sulfur content in the soil is the displacement of the alkaline Ca2+ and Mg2+ cations from the sorption complex and, consequently, acidification of the soil and increased mobility of the trace elements (Menz and Seip 2004). In ecosystems affected by increased sulfur deposition, microbial activity is reduced, followed by disturbed biogeochemical cycles and mineral nutrition (Menz and Seip 2004). In the previous century, increased concentrations of SO2 in the atmosphere associated with fossil fuel combustion, wet deposition, and acid rain were reported (Zhao et al. 2003). Despite the reduction of sulfur deposition in recent decades, there are still some sulfurcontaminated soils, and in consequence, there is still a need to study the negative impact of sulfur excess on soil properties (Stern 2005; Sołek-Podwika et al. 2016). The problem of excessive sulfur concentration concerns especially open-strip lignite mining sites made of Miocene sands with high carbon content, where affects the microbiological soil properties and plants growth (Katzur and Haubold-Rosar 1996). Sulfurous and acidic soils also occur in areas with processing plants and in the former sites of mineral mining with the Frasch method (method of mining, where sulfur is melted underground using superheat to 140–160 °C water under high pressure and pumped as a slurry) (Larssen and Carmichael 2000; Liu et al. 2010; Likus-Cieślik et al. 2015, 2017). Such areas are unique research sites to assess the impact of high sulfur content on changes of other properties of the reclaimed soils in the biogeochemical sulfur cycle in the restored ecosystem. One of the largest known sulfur deposits in the world is the bed located in the Tarnobrzeg district in southern Poland. The Frasch method sulfur mine Jeziórko occupied a site of about 2140 ha. Between 1993 and 2010, about 1179 ha were reclaimed (Likus-Cieślik et al. 2015). After end of sulfur extraction in Jeziórko sulfur mine, part of the area (705 ha) was reclaimed and afforested. Reclamation treatments consisted mainly of sulfurous horizon isolation in the top soil layer and neutralization of soil acidity with post-flotation lime (lime-containing sludge from the flotation enrichment process of native sulfur mined in Machów; the flotation lime contained on average 70.4% CaO and 0.24% Mg). Despite the reclamation measures, hotspots with high sulfur content in soils and acidification were found in mine lands (Likus-Cieślik et al. 2017). The observed soil sulfur concentrations reached up to 4% in the upper horizon (0–20 cm). This resulted in the inhibition of plant succession (Likus-Cieślik et al. 2017).