Trwalosc Lolium perenne w zaleznosci od stosowanych zabiegow pratotechnicznych

The perennial ryegrass (Lolium perenne L.) is a valuable species frequently used to establish permanent grasslands and to renew them. This study is an attempt to evaluate the viability of the ‘Arka’ cultivar in mountainous area with different management systems. From 1992 to 1997 three field experiments had been conducted. In the first a hay meadow set up on arable land was involved and the perennial ryegrass was sowed alone or in a five-species mixture. The meadow was cut twice a year and fed with minerals (P₂O₅ - 60; K₂O - 80; and N - 120 kg ha⁻¹). The second experiment was carried on a pasture renewed by undersowing with perennial ryegrass in a mixture with white clover. The pasture was grazed four times a year and fed respectively with 60, 80 and 60 kg of P₂O₅, K₂O and N per hectare. The third experiment was located on a permanent pasture and aimed at the evaluation of a specific Lolium perenne ecotype as to its response to different grazing regimens (grazed 4 or 5 times a year) and to the increasing dose of nitrogen fertilisation (60, 120 or 180 kg ha⁻¹). The other nutrients (P₂O₅, K₂O) were used on the same level. These experiments have proved a poor durability of perennial ryegrass cv. ‘Arka’ both on the meadow and on the pasture as well. In three-year period its content in the total crop of the grassland has radically decreased. In the pasture experiment the local ecotype of Lolium perenne was characterised by remarkable durability and its growth was especially stimulated by intensive grazing with N-fertilisation level of 120 kg per hectare