Fitness of Poa Nemoralis and P. Supina for Use As Winter Overseeding Species in the Transition Zone On Bermudagrass Putting Greens, Fairways, and Sports Fields.

Hybrid bermudagrass [Cynodon transvaalensis (Burtt-Davey) x C. dactylon (L.) Pers.] or Common Bermudagrass [C. dactylon (L.) Pers.] turfs are often overseeded with cool season grass species to provide green cover during winter months. Though beneficial, overseeding does have negative side effects, such as the transition from the overseeded species back to bermudagrass in the spring, which can be inconsistent and unpredictable. Though cultural methods may be used to facilitate the transition process many practitioners choose herbicides as a chemical transition tool, but both these methods add cost and labor to the process. The following study evaluated potential species that may provide a spring transition that is not dependent on herbicides or disruptive cultural methods while maintaining beneficial characteristics such as fast germination and establishment, uniform cover, and good winter growth and color. The study was initiated on 26 September 2010 at the East Tennessee Research and Education Center in Knoxville, TN and carried out during the 2010 to 2011 and 2011 to 2012 growing seasons. The effects of these species were investigated on three different turfgrass systems including a ‘Mini Verde’ putting green at a mowing height of 3.5 mm, ‘Riviera’ fairway at 15.8 mm, and a ‘Tifway’ sports turf at 22.2 mm with 10 simulated football games. On all three systems, a herbicide (Monument) was applied as a second factor at 37g/ha applied 6 May to facilitate transition for comparison. Putting green treatments consisted of ‘Enhary’ and ‘SRX 2NEM’ (P. nemoralis L.), ‘Supranova’ (P. supina Shrad.), ‘Sabre 4’ and ‘Quasar’ (P. trivialis L.), ‘Champion GQ’ perennial ryegrass (Lolium perenne L.) blend, and a non-overseeded control. On the fairway and sports turf studies, treatments consisted of ‘Gulf’ Annual ryegrass (L. multiflorum Lam.), ‘Transcend’ intermediate ryegrass (L. multiflorum x L. perenne), ‘Champion GQ’ perennial ryegrass blend, ‘Sabre 4’ and ‘Quasar’ P. trivialis, ‘Enhary’ and ‘SRX 2NEM’ P. nemoralis, and a non-overseeded control. On all three studies, percent green turf cover was collected using digital image analysis beginning 2 weeks after seeding (October) and ending once full transition occurred on all treatments (July). Significance in turf cover occurred on several dates with different species performing best at different times through the season. Species composition of each plot was determined beginning in late spring by using a 1 m2 grid with intersects on 10 cm centers. This data showed significant differences in transition timings. P. nemoralis transitioned out the fastest while P. supina was the slowest.