دانلود رایگان مقاله انگلیسی شیمی خاک آلوده شده با گوگرد، لایه گوگرد استخراج شده از معدن در شکل های گوناگون زباله - اشپرینگر 2018

Abstract

The impact of tree litter on soil chemistry leachate and sulfurous substrates of mine soils from former Jeziórko sulfur mine was investigated. Composites were used: soil substrate (less contaminated at mean 5090 mg kg−1 S or high contaminated at 42,500 mg kg−1 S) + birch or pine litter and control substrate (no litter). The composites were rinsed with distilled water over 12 weeks. In the obtained leachate, pH, EC, dissolved organic carbon, N, Ca, Mg, Al, and S were determined. Physicochemical parameters of the substrates and their basal respiration rate were determined. Rinsing and litter application lowered sulfur concentration in high contamination substrates. Pine litter application decreased EC and increased pH of the lowcontaminated substrate. The substrate pH remained at low phytotoxic level (i.e., below 3.0), resulting in the low biological activity of the composites. Birch litter application increased leaching of N and Mg, indicating the possibility of an intensification of soil-forming processes in contaminated sites.

4 Discussion and Conclusions

Tree species litter affects soil properties by changing pH, nutrient content in the topsoil horizons, and the dynamics of organic carbon accumulation in soils (Hobbie et al. 2010; Vesterdal et al. 2008; Mueller et al. 2012). In forest habitats, especially on poor sandy soils sites, nutrients are mainly stored in the organic horizons (litterfall). Next, they are gradually released via mineralization processes (Baule and Fricker 1973). This process is important in providing nutrients to trees in oligotrophic condition, as a limited amount of nutrients in the soil can be replaced by the rapid biological cycling of elements from the organic horizon (Woś and Pietrzykowski 2015). Similarly as in natural forests, organic matter is important in tree nutrient balance in newly developed ecosystems on reclaimed and afforested post-mine sites characterized among others by lack of soil organic matter (Pietrzykowski and Krzaklewski 2007; Urbanová et al. 2014). Organic matter improves water retention and is a source of nutrients for plants and soil biota in the newly developed postmine ecosystem (Frouz 2008). The results indicate that the rate and amount of leached elements depended primarily on the amount of sulfur concentration in the substrate. After 12 weeks of the experiment, a significant reduction of sulfur content was observed in HS composites but no effect of litter addition was found. It was observed that despite significant reduction of St content in the HS composites, the degree of sulfur contamination was still very high. According to the values reported by Polish Institute of Crop and Soil Fertilization, it even exceeded by 35-fold very high sulfur content (heavy contamination), i.e., above 1000 mg kg−1 (Kabata-Pendias et al. 1995). Results in the LS variant indicate that pine litter had a significant impact on EC reduction and increased pH in the soil substrate. However, after 12 weeks of rinsing, the substrate pH (below 3.0) was still toxic to plants and most microorganisms. Low substrate pH may be related to litter decomposition when organic acids are released and a decrease of soil pH (Augusto et al. 2002). However, the main cause of acidification of substrates and soil solutions was high sulfur concentration.