The Międzyodrze area in the Lower Odra Valley is filled with one of the larger peat deposits in Poland; its fragments occur even in the Szczecin agglomeration.

This vast and hardly accessible landscape of swamps and marshy meadows as well as the rich diversity of flora and fauna species contributed to the establishment of Polish–German Landscape Park on the area of 60.09 km² in 1993. The Gryfiński Polder is situated in the centre of the Park.

The studies were conducted within the Gryfino-Mesherin transect on six study areas drilled to determine the thickness of peat deposit. The bulk soil samples (in two replications) from the depth of 0–10 cm and 10–30 cm and the samples of grassland vegetation were also taken.

It has been found that the surface layer of peat (0–30 cm) is developed from muck with mud admixture and contains a varying amount of organic matter (15.1 to 82.0%). Its reaction is mostly strongly acid (pH 4.07–4.78), and the C : N ratio is 11.2–13.8 : 1.

The content of elements soluble in HNO₃ + HCIO₄ in the 0–30 cm layer was on average (g kg^–1): K – 3.66; P – 0.78; Mg – 4.0; Ca – 16.8; Na – 0.9.

The average content of heavy metals (mg kg^–1) was on, as follows: Cd – 3.1, Pb – 60.8, Zn – 184.9, Cu – 37.6, Ni – 38.3, Mn – 225.1, Co – 8.1. Within the area under study, the following grass communities were found: Carex acuta with Calamagrostis canescens, Calamagrostis canescens with Carex acuta and Glyceria maxima. Glyceria maxima contained the greatest amount of macroelements, whereas Carex acuta had the highest level of Cd, Zn, Ni and Mn.

Keywords: organic soils, grassland vegetation, chemical element content