Carbon, Nitrogen and Sulphur Pools and Fluxes in Pyrite Containing Reclaimed Soils (Technosols) at Gabra Village, Bulgaria

Abstract

The present paper deals with the characteristics of C, N and S pools and fluxes in pyrite containing Technosols located in the area of Chukurovo mine (Gabra village, Bulgaria) in a view of nutrient geochemical transformations in a specific technogenic environment. The role of vegetation and soil microbiota for stabilization of nutrient pools and fluxes has also been taken into consideration. Chemical and microbiological assays are used to analyze the contents and transformation rates of C, N and S. Determination of C:N and C:S ratios filling out the knowleadge of interactions between studied nutrients in pyrite containing environment. Cinnamon forest soils /Endogleyic Luvisols (Siltic, Chromic) are also included in the study in order to provide a basis for comparison. According to the results obtained carbon and nitrogen geochemical pools are interlinked by organic matter in Gleyic Technosols (Siltic). Soil microbiota predominantly manage nitrogen organic and inorganic fluxes and presumably are the main reason for low saturation of organic matter with nitrogen (C:N=11). In young Technosols /Stagnic Technosols (Clayic)/prevail the pools of coal carbon and the scarce fluxes of nitrogen. The average value of C:N is 38 but still the strong correlation between elements exists. Pyrite is the main source of sulfur providing predominance of inorganic pools and fluxes. It conceals the natural interlink beteewn carbon and sulphur organic pools resulting in very low values of C:S (average value of 7.5). Microorganisms responsible for the oxidative turnover of inorganic sulfur compounds prevail and further sustain the acidic pH in young soil solum.