EN
The aim of studies established in 1994 was evaluation of persistency of Trifolium repens and Lolium perenne in pasture sward under drier and postboggy habitat. Seed mixtures contained 50% of white clover and 30% of perennial ryegrass. Nitrogen fertilisation was differentiated in dependency on soil type: 90 kg on black soil And 45 kg ha⁻¹ year⁻¹. Content of white clover and perennial ryegrass in the sward depended on type and moisture of soil and sequence of regrowth in pasture season. Two first years of studies were very dry and then better white clover development was observed in wetter habitat. Among two white clover cultivars Rema proved to be more suitable on moister organic soils whereas Lithuanian cultivar Bitunaj on drier mineral ones. Those cultivars showed higher stability in the sward during the grazing season in more suitable habitats for them. Fast growing Lolium perenne was a dominant species in the harvest year, particularly on black soil, even during very dry vegetative season. Low tolerance to frost was the main reason of decrease of that species content in the pasture sward on both soils after 1995-1996 winter. In dry 1996 year there was observed better regeneration of ryegrass under postboggy habitat. During wetter following years ryegrass became again the dominant species on black soil. Presence of Trifolium repens in the pasture sward affected beneficially development and maintenance of Lolium perenne, especially in drier habitat. Floristic biodiversity of plant communities on peat-muck soils is rather low therefore introduction and maintenance of white clover and perennial ryegrass in pasture sward is needed to avoid Poa sp. and Festuca rubra expansion.