Productivity and Persistence of Multi-Cultivar Perennial Ryegrass Mixtures.

Perennial ryegrass is an exceptionally high quality forage grass but its use in the northeast has been limited because it is typically not as winter hardy as other perennial forage grasses. This can be a particularly difficult problem for winters such as 2013-2014 which experienced wide-spread and long lasting cold conditions. Substantial research over the years has shown that pasture productivity can be improved by sowing multiple species from different functional groups but little is known about the benefits, if any, of sowing multiple cultivars within a species. This multi-state project (ME, NH, VT, and PA) compared the productivity and persistence of 1-, 3- and 5-cultivar mixtures of perennial ryegrass selected for differences in heading date, winter hardiness, and ploidy. Plots contained white clover as a nitrogen source and were managed according to organic farming practices. Cultivar mixtures had no significant effect on total dry matter yield in 2013 (p = 0.13), although a mixture comprised solely of tetraploid cultivars had significantly lower early season yield than most other treatments. Averaged across treatments and locations, the proportion of perennial ryegrass in the harvested biomass decreased from 84% in spring 2013, to 62% in fall 2013, to less than 20% in spring 2014. The greatest decrease occurred in Pennsylvania (98% perennial ryegrass in spring 2013 vs. 7% in 2014).