A b s t r a c tThe characteristics of communities developing in cereal crops of the Mazowiecki Landscape Park are presented in the paper. The traditional methods of cultivation, a mosaic of fields, meadows and forests as well as a specific microclimate affect the occurrence of species-rich, syntaxonomically differentiated agrophytocenoses. The occurrence of 4 associations and 2 communities in the area of the Park was noted. On the poorest soils, the association Arnoserido-Scleranthetum was the most widespread and internally differentiated, whereas in more fertile habitats the association Vicietum tetraspermae was the commonest. The above mentioned associations were noted more frequently in winter crops than in spring cereals. Plots of the association Papaveretum argemones and intermediate communities, between Arnoserido-Scleranthetum and Papaveretum argemones, were seldom observed in the studied area. Plots with domination of species diagnostic for the order Polygono-Chenopodietalia occurred rarely in spring cereals, mainly in the protection zone of the Landscape Park. Single, impoverished plots of Aphano-Matricarietum were recorded in the south-eastern part of the Park.

Plant communities of the cultivated fields of the Podlaski Prze³om Bugu mesoregion. Part 2. Cereal communities (Otrzymano: 20.12.2004) S u m m a r yPresence of communities without species characteristic for cereal associations was observed in the cultivations of the Podlaski Prze³om Bugu mesoregion. Community Scleranthus annuus and community with species characteristic for alliance Aperion spica-venti were observed in winter cereals. Phytocoenoses similar in floristic composition to root cultivations were noted in spring cereals of the studied area. Plots of communities with participation of species characteristic for alliance Panico-Setarion were observed on loose soils while on more compact and fertile habitats community with species characteristic for Polygono-Chenopodion was noted.

S u m m a r yCharacteristic of plant communities developing in the cereal cultivations of the Podlaski Prze³om Bugu mesoregion is presented in the paper. This agricultural region is partially situated in the borders of the ,,Podlaski Prze³om Bugu" Landscape Park. Extensive agriculture as well as large soil and microclimatic diversity resulted in occurrence of rich, floristically differentiated agrocoenoses. Three associations from the alliance Aperion spicae-venti were noted in the studied area. Association Vicietum tetraspermae was the most common and inner differentiated. Four subassociations: Vicietum tetraspermae scleranthetosum, Vicietum tetraspermae myosotidetosum, Vicietum tetraspermae typicum, Vicietum tetraspermae consolidetosum and 18 lower syntaxonomic units were distinguished. Plots of Papaveretum argemones, differentiated into 3 subassociations: Papaveretum argemones scleranthetosum, Papaveretum argemones typicum and Papaveretum argemones consolidetosum were noted seldom in the studied area. In the central part of the Podlaski Prze³om Bugu mesoregion occurrence of a single plots of Arnoserido-Scleranthetum was noted.

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The paper presents the diversity of weed communities growing in different crops (winter cereals, spring cereals, and tuber plants) and in diverse soil conditions. To determine weed diversity, phytosociological relevés were made. Simpson’s index of dominance and the Shannon index of biodiversity for weed communities in different crops growing in different soil conditions were calculated and compared. The highest values of the Shannon index and the lowest values of Simspon’s index of dominance were obtained for weed communities noted on compacted and semi-compacted soil with the following granulometric composition: silty loam with underlying sand at a depth of 100 cm, heavy silty sandy loam, silt with underlying sand at a depth of 50 cm, and silt with underlying sand at a depth of 100 cm. The highest index of dominance and low species diversity were determined for weed communities in light soils. The Shannon index of biodiversity was moderately positively correlated with soil pH and granulometric composition. Simpson’s index of dominance was moderately negatively correlated with granulometric composition and was weakly correlated with soil pH.