Persistence of Perennial Ryegrass, Cocksfoot, Tall Fescue and Grazing Bromegrass Cultivars in Binary Mixtures with White Clover Under Grazing.

The persistence of highly productive forage species in pastures is essential to maximize economic returns from grazing livestock. However, most forage cultivars are neither selected nor evaluated under grazing. To test the persistence of different cultivars from four different grass species (Lolium perenne L., Dactylis glomerata L., Festuca arundinacea Schreb., Bromus stamineus Desv.) under grazing, a five-year plot trial was conducted on commercial dairy farms located in different climatic conditions in Switzerland. Plots were arranged in a randomized, complete block design with three replicates. Cultivars (seven perennial ryegrass, three cocksfoot, one tall fescue and one grazing bromegrass) were sown in binary mixtures with white clover (Trifolium repens L.) in autumn 2007 and spring 2008. The relative frequency of the grass cultivars was evaluated in 2009 and 2012 to determine their long-term tolerance to grazing. Across all sites, the tall fescue cultivar showed the best persistence, while the brome grass cultivar showed the poorest. The mean persistence of the cocksfoot and perennial ryegrass cultivars were similar. Statistical analyses show a significant interaction between sites and species. For the perennial ryegrass cultivars, a significant site and cultivar interaction could be observed. The tested cocksfoot cultivars showed a similar persistence which differed among sites. The findings reveal the importance of the site and its management for the performance of the species and cultivars and suggests a need for site-specific breeding and testing of cultivars.