Tolerance of perennial ryegrass (Lolium perenne) cultivars to simulated fall traffic

Perennial ryegrass is used widely for sports turf surfaces in the mid-Atlantic region of the United States. Although many cultivars of perennial ryegrass are available to sports turf managers, little is known about their relative tolerance to traffic. The objective of this study was to evaluate the response of 88 cultivars from the 2010 National Turfgrass Evaluation Program Perennial Ryegrass Test to a program of intensive simulated fall traffic using a Brinkman Traffic Simulator. Percent ground cover of traffic and no-traffic plots were assessed during 2011 and 2012 using digital images taken prior to initiation of traffic treatments, at the conclusion of traffic treatments in fall, and the following spring. Results of fall traffic tolerance (difference between percent ground cover assessments before and after fall traffic treatments) showed the main effect of traffic treatment was significant (P≤0.001). However, the main effect of cultivar and the cultivar × traffic interaction were not significant (P≤0.66 and P≤0.88, respectively) when data from 2011 and 2012 were combined. All cultivars showed good recovery from traffic treatments in spring (expressed as the difference between percent ground cover after traffic in fall and percent ground cover following a recovery period in spring). Four cultivars, 'A-35', 'BAR Lp 7608', 'CS-PR66', and 'PSRX-4CAGL', showed higher recovery values than 'Sienna', a stoloniferous ryegrass. No differences were detected between these five cultivars and the other 83 cultivars. The lower recovery value of 'Sienna' was probably a result of having the highest percentage of ground cover in late fall, and the four other cultivars having low ground cover values in late fall.