Date of Award
Doctor of Philosophy
Plants, Soils, and Insects
John C. Sorochan
James T. Brosnan, Dean A. Kopsell, Thomas J. Samples, Alan S. Windham
Warm-season turf species are becoming increasingly popular for putting green use in the transition zone. Ultradwarf bermudagrass (Cynodon dactylon (L.) C. transvaalensis Burtt-Davy) is the prevalent warm-season putting green species, but seashore paspalum (Paspalum vaginatum Swartz) and ‘Diamond’ zoysiagrass [Zoysia matrella (L.) Merr.] may also be grown in the transition zone. Warm-season species are susceptible to winter injury and may require different management regimes than cool-season species. Therefore, the objectives of this research were to assess the impacts of various management practices on warm-season putting green species and characterize the physiological basis for differences in freeze tolerance of various warm-season putting green species. Field studies determined sampling procedures form thatch-mat depth and soil organic matter content of warm-season putting greens and assessed the impact of various management practices on different warm-season putting green species/varieties. The relative freeze tolerance of ‘Champion’ and ‘TifEagle’ ultradwarf bermudagrass cultivars, ‘SeaDwarf’ seashore paspalum, and Diamond zoysiagrass were determined, along with the accumulation of proline and polyamines during cold acclimation, in growth chamber studies.
All species/varieties required different sampling numbers for determination of thatch-mat depth and soil organic matter. More sand was incorporated into the turf canopy and surface hardness was increased with brushing and vibratory rolling TifEagle putting greens after sand topdressing application than either treatment alone. Putting green management programs with lower mowing heights and increased mowing frequencies increased ball roll distance on a MiniVerde putting green without negatively affecting turf quality. Weekly vertical mowing + daily grooming on TifEagle reduced thatch depth and turfgrass quality, while increasing topdressing incorporation over either treatment alone.
Diamond was the most freeze tolerant species/variety, followed by TifEagle, Champion, then SeaDwarf. Cold acclimation increased proline concentration for all species/varieties except SeaDwarf, but had inconsistent effects on polyamines. Spermidine and putrescine concentrations differed with species/variety, but were not correlated to freeze tolerance.
Kauffman, John M., "Investigating Cold Hardiness and Management Practices of Warm-season Putting Green Species in the Transition Zone. " PhD diss., University of Tennessee, 2010.