Changes in species composition of meadow mixtures with differential earliness of grass cultivars in 3-year utilization

The studies were carried out in 1990-1992 in Jaktorów (central Poland) at a natural, moderatly wet site on mineral soil. The objects were four mixtures: early, medium-early, medium-late and late. The aim of this study was to evaluate the changes of botanical composition of meadow mixtures in yields during 3-year utilization. The choice appropriate cultivars made possible first cut different mixtures at the same developmental stage mostly within two weeks (exceptionally during 7 days in a dry year). Changes in the botanical composition of mixtures, noticeable since the first utilization year, did not alter their phenological type in the study period. That was determined first of all by four cultivars of Dactylis glomerata - a dominant species in all mixtures