Seedling Emergence and Establishment of Agrostis Cultivars on a Putting Green Following Simulated Winterkill.

Low soil temperatures during early spring present a challenge for golf course superintendents attempting to establish creeping bentgrass (Agrostis stolonifera L.; CBG) following winterkill. The objective of this study was to elucidate differences in the rate of seedling emergence and establishment among various CBG cultivars in the early spring. A field study was conducted at the Joseph Valentine Turfgrass Research Center in University Park, PA to assess the establishment of 25 CBG cultivars when seeded into a putting green following a simulated winterkill. Immediately prior to seeding, the entire area was core-cultivated and vertically mowed in two directions to prepare a seedbed. Plots (0.9 x 1.8 m) were seeded on 30 March 2017 at a rate of 73 kg pure live seed ha^-2. Seed was mixed with Milorganite (342 kg ha^-2) and applied by hand using shaker jars. Following seeding, the entire area was fertilized at a rate of 24 kg N ha^-2, topdressed with sand, covered with an Evergreen Turf Cover and rolled. The experimental design was a randomized complete block design with four replications. Seedling vigor was evaluated visually every 3 to 4 days using a 1 to 9 scale where 1 = no emergence and 9 = uniform emergence over the entire plot area. Percent ground cover was rated visually each week on a 0 to 100 scale. All data were analyzed using the MIXED procedure in SAS. On average across all rating dates, individual seed lots of cultivars ‘007’, ‘V-8’, ‘SR1150’, and ‘Pure Select’ had the highest seedling vigor. By 2 June, one treatment seeded with the cultivar ‘V-8’ had the highest percent cover (84%), but was similar to thirteen other cultivars evaluated (69 to 84%).