Root Zone Construction Affects Hybrid Bermudagrass (C. Dactylon x C. Transvaalensis) Responses to Simulated Traffic

Abstract

Few studies have directly compared the types of root zones used for athletic fields. A two-year field study was conducted from 2012-2013 at the University of Tennessee Center for Athletic Field Safety (Knoxville, TN) to compare the performance of four root zones: a silt loam root zone, a sand-based root zone constructed to United States Golf Association (USGA) specifications, a sand-based root zone constructed to ASTM International (ASTM) specifications, and a sand-cap root zone (CAP) consisting of silt loam capped with 15cm of sand that conformed to USGA particle size specifications. Hybrid bermudagrass (C. dactylon x C. transvaalensis, cv. ‘Tifway’) was established over all root zones. In addition to the bermudagrass treatments, two different synthetic turf surfaces varying in fiber type and infill ratio were included for comparison. All treatments were subjected to 30 simulated traffic events each autumn at rates of 0, 3 or 10 simulated traffic events per week in a split-plot design. Differences were only detected in percent green cover only for traffic rate in 2012. In 2013, bermudagrass on silt loam was reduced to 50% cover after ∼10 simulated traffic events, compared to ∼18 simulated traffic events on USGA and ASTM sand-based root zones. Surface hardness varied between treatments and years of the study; however, at no time did any surface exceed surface hardness thresholds associated with head injury (200 Gmax). Despite the loss of hybrid bermudagrass cover from the repeated simulated traffic events, few differences in surface hardness were detected between synthetic turf and hybrid bermudagrass plots in this study, regardless of root zone.