Monika Jakubus, Piotr Gajewski, Zbigniew Kaczmarek
Uniwersytet Przyrodniczy, Poznań
Organic soils account for a small percentage of agriculturally utilised soils and are used primarily for meadows and pastures. A characteristic feature of these soils is connected with considerable contents of organic matter, which significantly modifies their physico-chemical and chemical properties. Water is another important factor determining productivity parameters of organic soils. Changes in water and air relations contribute to adverse changes in most soil properties, thus deteriorating agricultural value of soils. In view of the fact that in the vicinity of open-cast lignite mines drainage of organic soils is a more frequent phenomenon studies were undertaken to assess physico-chemical and chemical properties of soils located in such areas. Analyses were performed on mean bulk samples coming from surface layers of 7 soil profiles located in the vicinity of the Tomisławice open-cast mine. According to the WRB classification (2006) these soils were: Mollic Gleysol (profiles 1–3), Fibric Sapric Histosol (profile 4), Histic Gleysol (profile 5), Sapric Histosol (profile 6) and Limnic Histosol (profile 7). The study analysed the following physico-chemical properties: soil reaction, hydrolytic exchange (Hex), base saturation (BS), cation exchange capacity (CEC), index of soil complex saturation with base cation (V) as well as organic matter (OM) and total carbon (Ctot) content. The analysed chemical properties included total and available contents of macronutrients (N, P, K, Ca, Mg, S, Na) and microelements (Fe, Zn, Mn, Cu, Ni). Investigated soil properties were assessed on the basis of methods commonly applied in analyses of organic soils. Surface layers of analysed soils were characterised by broad ranges of contents for most investigated properties. Soils classified as Mollic Gleysol (profiles 1–3) had lower contents of M.O. and Ctot at higher values of Hw, BS and CEC in comparison to the other tested deposits. Generally soils from profiles 4–7 were characterised by greater contents of analysed macronutrients, both in their total and available forms. Irrespective of the soil deposit, surface horizons contained the greatest amounts of total nitrogen (4.27–22.25 g·kg-1) and the lowest contents of total sodium (65.73–105.55 mg·kg-1). Available amounts of macronutrients were highest for calcium (1.06–3.66 g·kg-1) and lowest for sodium (8.80–21.36 mg·kg-1). Quantitative variability shown in relation to microelements was considerable, mainly in case of iron, manganese and zinc. At the same time in the surface layers of the analysed soils the greatest amounts of total iron (2.10–32.63 g·kg-1) and available iron (0.47–20.00 g·kg-1) were recorded along with the lowest contents of total nickel (0.90–11.27 mg·kg-1) and available nickel (0.75–4.63 mg·kg-1). Total and available amounts of microelements were generally greater in Mollic Gleysol (profile 1–3). Irrespective of the presented quantitative differences, analysed soils were mostly characterised by limited resources of available phosphorus and potassium, and average levels of available manganese, zinc and copper.
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