The complex of Czersk Meadows, irrigated since the middle of the 19th century with the strip-flood system, is unique on the European scale. The aim of this study was to estimate the content of organic carbon, total nitrogen and dissolved fraction of organic matter in conditions of long-lasting irrigation of grasslands. The studied areas included Czersk Meadows, irrigated for more than 150 years, and the areas that were not irrigated for more than 25 years (Green Meadows). The study area is characterized by rusty soils with features of podsolization (RWbi – Albic Brunic Arenosols (Distric)). Soil samples were collected from surface and subsurface horizons: A, AE, Bsv. There were determined as follows: the total content of organic carbon (TOC), total nitrogen (Nt) as well as dissolved organic carbon (DOC) and dissolved nitrogen (DNt). Higher accumulation of organic carbon and total nitrogen was found in the humus horizon of soils of systematically irrigated meadows as compared with the soils of meadows that were stopped to be irrigated. The contents of TOC and Nt in soil samples collected on Czersk Meadows increased along with the distance from irrigation ditches. Soils of irrigated meadows were characterized by a wider TOC/Nt ratio than the soils of not irrigated meadows. Constant irrigation of meadows also resulted in a high proportion of DOC and DNt in the humus horizon (A) of soils.

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