Content of potassium and magnesium in organic soils and meadow vegetation of Szczecin Pomerania

Abstract

The studies included the major organic meadow soils of Szczecin Pomerania, left fallow or sporadically used extensively. The following determinations were made: the content of plant available magnesium and potassium (using HCl at the concentration of 0.5 mol⋅dm 3 ), their total forms (soluble in the mixture of concentrated acids HNO 3 + HCIO4) as well as the content of potassium and magnesium in the meadow-pasture sward from the area under study. The results are presented in Table 1. The investigated peat-muck, gyttiamuck, mineral-muck and muckous soils, in the surface layer 0-30 cm deep (which was primarily the muck layer) mostly contained the amounts of potassium and magnesium typical of organic soils when soluble in the mixture of concentrated acids HNO3+HCIO4 but low and frequently very low amounts of potassium soluble in 0.5 mol⋅dm-3 HCl from (0.04 to 0.51g⋅kg-1). The content of this form of potassium depended on the degree of peat siltation. Low resources of available potassium were caused by the deficiency of this element in the meadow pasture sward since only in the sward of the Gryfinski Polder in Miedzyodrze and the sward from gyttia-muck soils near Miedwie Lake the optimum amounts were detected (above 15.0 g⋅kg-1 dry matter). In comparison with these results, the content of magnesium, soluble in 0.5 mol⋅dm-3 HCl in these soils was more favourable to plants (generally above 0.40 g⋅kg -1 ), which is considered high according to the Institute of Soil Science and Plant Cultivation (IUNG 1990). In meadow sward, magnesium content mostly exceeded 2.0 g⋅kg -1 dry matter so either approached or reached the optimum value for