The research concerning the properties of the soils of the south-eastern area of Poland was carried out mainly in ecosystems which are of especially great importance in the water economy of the environment. Special attention was paid to the high-mountain meadow soils in the Bieszczady, deteriorated hydrogenic soils of the drained valley of the San River and alluvial soils of the San catchment. The uppermost organic layer of the soils plays an important protective, buffer and retension role. The examined youngest layer of the investigated alluvial soils is characterized by very valuable soil-forming properties.