‘Diamond' Zoysiagrass Ballspeed, Thatch and Trufirm Readings Under TE and Varying Levels of Nitrogen.

‘Diamond’ zoysiagrass (Zoysia matrella (L.) Merr) is a fine textured warm season turfgrass that is gaining popularity on golf courses in the transition zone and further south. Its shade and salt tolerance, excellent wear tolerance, and texture make it a turfgrass cultivar that is being evaluated for further use. To assess ‘Diamond’ in a putting green application a two year field study was conducted at the Cliffs Environmental Research Complex in Marietta, SC. The project focused on turfgrass performance under varying levels of ammonium nitrate and trinexapac-ethyl (TE). Treatments of 4.9 kg ha-1, 9.8 kg ha-1, and 14.7 kg ha-1 ammonium nitrate were applied with a Co2 pressurized backpack sprayer delivering 561 L ha-1. TE was applied at 0 L a.i ha-1 and 0.017 L a.i ha-1. Treatments in 2009 commenced July 28th and finished September 10th. 2010 treatments began May 20th and terminated in September. Ball speed and turf quality were measured weekly. Thatch accumulation and firmness were measured monthly throughout the study. Preliminary results indicate significant differences in turf quality among the treatments. The data shows that under TE a reduction in total nitrogen input is possible without sacrificing playability. Thatch accumulation and surface firmness appear to not be related and there were not significant treatment effects on either parameter. Additional results and observations will be compiled after year two of the study.