Heavy Sand and Crumb Rubber Topdressing Improves Kentucky Bluegrass Wear Tolerance

Sand topdressing and crumb rubber can be used to improve native soil athletic field playability. However, there is a wide range in the physical properties, price, and availability of these materials. The objective of this field research was to evaluate the effects of various topdressing materials on the autumn wear tolerance and surface stability of a well established Kentucky bluegrass (Poa pratensis L.) stand. Research was conducted on a sandy loam in East Lansing, MI, to evaluate the effects of four different sand-based materials with a range of physical properties, crumb rubber, a treatment that received sand then crumb rubber and a non-topdressed control. In the first summer, 4.8 cm of sand-based topdressing material, 2.4 cm of crumb rubber, and 2.4 cm of sand then 2.4 cm of crumb rubber was accumulated over their respective plots. Turf was subjected to simulated traffic using the Cady traffic simulator from mid-October through mid-November. In 2009, topdressing applications and subsequent traffic were repeated on the same experimental plots. Visual percent living ground cover (0 to 100%) and Clegg turf shear tester (TST) strength were measured. The control, while producing some of the greatest turf shear tester strength, provided the lowest turfgrass cover: 46.7% in 2008 and 35.0% in 2009. Crumb rubber, while being the most expensive topdressing material, provided the greatest turfgrass cover: 85.0% in 2008 and 90.0% in 2009. All sands provided comparable living ground cover and turf shear tester strength with the exception of a poorly-graded sand, which produced the lowest shear tester strength values in 2008.