Dormant Seeding Bermudagrass Into an Overseeded Ryegrass Turf.

ABSTRACT Dormant Seeding Bermudagrass into an Overseeded Ryegrass Turf   Seeding bermudagrass (Cynodon dactylon L. Pers.) during the winter has been shown to be an effective method to establish this species in the transition zone.  However, bermudagrass athletic fields are often overseeded with perennial ryegrass (Lolium perenne L.) during cool weather and it is unclear whether dormant seeding bermudagrass into an overseeded stand of turf would be equally effective. The objective of this study was to determine if dormant seeding could be used to establish bermudagrass into a site that was over-seeded with perennial ryegrass. The study was initiated in the fall of 2007 in Fayetteville AR on a bermudagrass (cv. Tifway) site that was treated with three sequential applications of glyphosate (1.12 kg ha-1) to kill the existing turf. The area was overseeded with perennial ryegrass (560 kg / ha) and maintained under simulated athletic field conditions during the fall and winter months. Treatments were initiated in early 2008 and included two factors, bermudagrass seeding date (Feb, April, and June) and herbicide suppression of the perennial ryegrass. Riviera bermudagrass was used for all seeding dates and seeded at 48.8 kg PLS ha-1. Herbicide treatments included a pre-seeding glyphosate application (1.12 kg ha-1) , four transition herbicide treatments (flazasulfuron at 0.018 kg ha-1, foramsulfuron at 0.030 kg ha-1, trifloxysulfuron at 0.017 kg ha-1, and pronamide at 1.12 kg ha-1) and an untreated control. Dormant seeding has only been effective in plots treated with glyphosate prior to seeding, suggesting that competition from perennial ryegrass may be too severe to utilize this method on overseeded athletic fields.