ASSOCIATIONS AND COMMUNITIES OF CEREAL CULTIVATIONS OF THE ŁUKOWSKA PLAIN PART II. ASSOCIATIONS OF HEAVY SOILS.

The paper is the second part of the work examining segetal communities of the Łuków Plain. It presents a description of phytocenoses establishing in cereal crops on heavy soils. Only Vicietum tetraspermae were found in these habitats. Neither patches of Consolido-Brometum nor communities representing the alliance Caucalidion lappulae were encountered. Floristic and ecological diversity of Vicietum tetraspermae was due to 8 syntaxonomic units distinguished in the study area: 3 subassociations (Vicietum tetraspermae typicum, V. t odontitetosum and V. t consolidetosum) and 6 variants within Vicietum tertaspermae typicum. Patches of Vicietum tetraspermae typicum were the most frequent in the study area whereas the remaining sub-alliances were much more rare. Of particular interest were species-poor patches of Vicietum tetraspermae typicum dominated by Vicia grandiflora found in the Łuków area which are indicative of the degradation of this alliance. [ABSTRACT FROM AUTHOR]