Evaluation of a Hybrid (Natural and Synthetic Turf Mixture) System for Athletic Field Use.

Hybrid athletic field systems containing both natural and synthetic turf have been used on athletic fields for several decades. A new hybrid system, commercially named XtraGrass, has recently been developed to incorporate both synthetic and natural turf into an athletic field use. However, little is known how to establish and manage the latest generation hybrid systems, and how they hold up to traffic. Field research was conducted at the University of Tennessee Center for Athletic Field Safety in 2014 and 2015 as a randomized complete block design. XtraGrass was tested in four separate trials including: tall fescue (Festuca arundinacea), bermudagrass (Cynodon spp.), Kentucky bluegrass (Poa pratensis), and Perennial ryegrass (Lolium perenne). Plots containing the hybrid system were compared to plots without the hybrid system. The tall fescue, perennial ryegrass, and Kentucky bluegrass were maintained at 3.2 cm height of cut, while the bermudagrass was maintained at 2.2 cm and clippings were removed with every mowing. Each playing surface was subjected to 5 simulated traffic events a week with the Cady Traffic Simulator for 6 weeks for a total of 30. Data were collected to test traffic tolerance with digital image analysis for percent green cover (after every 5 simulated traffic events), surface hardness (at 0, 15, and 30 simulated traffic events), and athlete-to-surface interactions with the Tennessee Athletic Field Tester (at 0 and 30 simulated traffic events). Percent green cover data were analyzed using non-linear regression techniques to determine the rate at which green cover was lost in response to traffic. Plots containing the hybrid system all offered a higher percent green cover throughout the study compared to plots without the hybrid system (For example: after 30 simulated traffic events the XtraGrass + Kentucky bluegrass reported 60% green cover while the Kentucky bluegrass only plots reported 40% green cover). After 30 simulated traffic events, surface hardness values were all less than a Gmax of 100 with the Clegg Impact Hammer. Athlete-to-surface interactions for peak horizontal and vertical forces were not significantly different prior to simulated traffic and after 30 simulated traffic events for the hybrid systems containing Kentucky bluegrass and bermudagrass, while significant differences in both peak horizontal and vertical forces were noted for Kentucky bluegrass and bermudagrass without the hybrid system. This indicated the lower limb interactions will be more consistent on a hybrid system than athletic fields without. These results can help athletic field managers improve traffic tolerance and athlete performance on athletic fields.