2017 ASHS Annual Conference

Fall overseeding of perennial ryegrass into bermudagrass fairways is a common practice to maintain a desirable green playing surface during winter and early spring. However, optimum seeding rates needed to achieve a speedy green coverage while bermudagrass enters dormancy are not known. A study was conducted at the New Mexico State University Golf Course in Las Cruces, NM to evaluate the effect of differing rates of fall overseeding of perennial ryegrass on percent green cover, turfgrass quality, and Dark Green Color Index (DGCI) during fall, winter, and spring following overseeding. Champion GQ, a commercially available blend of perennial ryegrasses containing the varieties Sideways (42%), Zoom (32%), and SR 4600 (26%) were seeded on 23 Sept. 2016 using rates of 33, 50, 66, 84, and 100 g m^-2. The study was laid out as a completely randomized block with a plot size of 1.5 m by 6 m replicated three times. Statistical analysis of the data indicated a significant effect of seeding rate and sampling month on percent green cover and quality. Seeding rate did not affect DGCI. Average turfgrass quality was highest on plots seeded at rates of 66, 84 and 100 g m^-2, reaching values of 7.9, 8.1 and 8.2 respectively. The two lowest seeding rates of 33 and 50 g m^-2 resulted in quality ratings of 6.9 and 6.6, respectively. Plots seeded at the lowest rate had significantly lower percent green coverage (89%) compared to plots seeded at rates of f 50, 66, 84, 100 g m^-2, which reached coverages of 94%, 95%, 97% and 96%, respectively. When averaged over all treatments, DGCI was highest in November (0.5308) and lowest during December (0.4666) and January (0.4701). Despite the wide range of seeding rates used in this study, turfgrass quality was above the minimum acceptable value for all rates during the duration of the study. Nonetheless, a seeding rate of 66 g m^-2 or higher resulted in better turf quality through the winter.