The paper presents the results of soil and floristic research conducted in the valley of the central course of Warta River in the “Nature 2000” area, which is located nearby KWB Adamów brown coal pit. The state of grasslands’ vegetation was characterized on the basis of its floristic composition, and such soil properties as texture, specific density, bulk density, porosity, maximal hygroscopic capacity, saturated hydraulic conductivity, the potential of water bonding and total and readily available water were analyzed. Grasslands located in the detention basin were diverse and the diversion depended mostly on their location and utilization. Foxtail, oatgrass, and fescue-poa grasslands were dominant, whose new growth is rich in species of economically useful herbs and weeds. Examined soils showed great variation in their physical and water properties. It stems out from their specific origin which was strongly conditioned by the fact that are much more influenced by geological than soil-formation processes. These changes were caused mainly by different texture of each genetic level and the character of sludge accumulation which influences the content of total carbon. The presented results did not differ significantly from typical values found in alluvial soils of Polish river valleys. The conducted pedological characteristics of habitats suggests that the examined area is not undergoing degradation due to the activities of an opencast mine located nearby. It has also been confirmed by the high level of soil and ground waters.