Evaluation of Crumb Rubber Dynamics for Improving Athletic Field Quality

Crumb rubber (CR) is an amendment used to reduce surface hardness and increase wear-tolerance on athletic fields. Turf managers can topdress CR particles into highly trafficked portions of athletic fields; however, optimum particle size and topdressing depth combinations for use on bermudagrass (Cynodon spp) athletic fields have not been determined. Optimum CR particle size and depth to maximize performance of hybrid bermudagrass (C. dactylon (L.) Pers. x C. transvaalensis Burtt-Davy, 'Tifway') athletic field turf established on a Sequatchie silt loam soil was investigated at the University of Tennessee Center for Athletic Field Safety (Knoxville, TN) in 2011 and 2012. The experimental design was a randomized complete block with four replications. Treatments included five CR particle sizes (30, 20, 10:14, 14:30, and 8:20 mesh size, respectively) and three topdressing depths (0.6, 1.3 and 1.9 cm, respectively). The coefficient of uniformity for each particle size tested was 1.83 (30 mesh), 2.28 (20 mesh), 1.82 (10:14 mesh), 1.38 (14:30 mesh), and 1.79 (8:2 mesh), respectively. All plots were subjected to 25 simulated traffic events with the Cady traffic simulator. In 2011, significantly greater green turfgrass cover was retained in 1.3 and 1.9 cm depths than the control. Surface hardness was significantly lower on 1.3 and 1.9 cm depth plots, whereas, particle size had no significant effect on surface hardness. However, no differences were observed in 2012. Our findings indicate that CR topdressing depth is more important than CR particle size in optimizing performance of hybrid bermudagrass athletic fields under simulated traffic.