Comparison of Productivity and Quality of Three Perennial Ryegrass Cultivars and Their Mixture in Response to Nitrogen Fertilization and Grass-Legume Mixtures

We conducted a four-year cutting experiment on herbage yield, with three years focused on testing the effect of perennial ryegrass (PR) cultivars 'Elena DS', 'Raminta', and 'Verseka', along with a cultivar mixture and compositions with white clover (WC) and red clover (RC) diversity, on crude protein (CP), modified acid detergent fibre (MADF), neutral detergent fibre (NDF), water-soluble carbohydrates (WSC), and dry matter digestibility (DMD) content. PR cultivars and cultivar mixtures were sown alone (N₁₅₀), and the PR 'Elena DS' and PR cultivar mixtures were also sown with each WC, or WC and RC (N₀). The average four-year herbage productivity was the lowest in PR 'Elena DS' the and cultivar mixture/WC, followed by all of the pure PR swards, and the highest in PR 'Elena DS' and the cultivar mixture/WC+RC; however, the PR 'Elena DS'/WC+RC mixture had the highest legume proportion and CP content. There was less NDF but also WSC in swards with legumes, but higher CP content than in pure PR swards; however, the highest CP content was in mixtures with RC. Among the grasses, PR 'Verseka' had lower NDF contents and a higher WSC than PR 'Elena DS', 'Raminta', and the cultivar mixture. Overall, this study revealed significant differences in the productivity of PR cultivars with a potential yield difference of up to 1.7 t ha^-1.