Some factors influencing production of sulphate by oxidation of elemental sulphur and thiosulphate in upper horizons of spruce forest soils

Abstract

Some factors influencing the oxidative activity of upper horizons of spruce forest soils (a mixture of fermentative and humus layers) toward intermediates of the oxidative part of the sulphur cycle were investigated. Preincubation of the soil with added cysteine, sulphide, elemental sulphur or thiosulphate was found to stimulate enzyme systems oxidating any of these compounds. Sulphite and sulphate were ineffective in this respect. The oxidation of elemental sulphur was stimulated by CaCO3, technical urea and high doses of superphosphate and potassium sulphate. It was inhibited by KH2PO4, pure urea, 40 % potassium salt, ammonium nitrate with calcium carbonate and the fertilizer NPK I. It proceeded at the highest rate at approximately 60 % capillary capacity (61 % of mass water content). Oxidation of thiosulphate was stimulated by KH2PO4, pure urea, superphosphate, potassium sulphate and only slightly by the fertilizer NPK I. It was inhibited by CaCO3, 40 % potassium salt and only slightly by ammonium nitrate with calcium carbonate. Potassium chloride, glucose and technical urea were without effect. The oxidation proceeded at the highest rate at 35 % maximal capillary capacity (48 % mass water content).

Changes in Soil Sulfate Sulfur Content as an Effect of Fertilizer Granules Containing Elemental Sulfur, Halloysite and Phosphate Rock

“…This is due to the effect of high osmotic pressure [42]. In contrast, the greater efficiency of this process in alkaline soil is due to the higher content of calcium carbonate (CaCO 3 ) [43]. As the abundance of organic matter in the soil increases, the living conditions for microorganisms improve.…”