Selecting the Proper Topdressing Material for High Traffic Areas.

Research has shown that sand topdressing and crumb rubber can be used to improve native soil athletic field playability characteristics.  However, there is a wide range in the physical properties, price and availability of these materials.  The objective of this research was to evaluate the effects of various topdressing materials on the fall wear tolerance and surface stability of a well established Kentucky bluegrass (Poa pratensis L.) stand.  Research, utilizing a randomized compete block design, was initiated on a Colwood loam (fine-loamy, mixed, active, mesic Typic Endoaquoll) in East Lansing, MI, on 17 April 2008.  Topdressing material included four different sand-based materials, with a range of physical properties, crumb rubber, a treatment that received sand then crumb rubber and a control, which did not receive topdressing.  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.  Fall traffic was then applied from 15 October to 14 November 2008 using the Cady traffic simulator.  In 2009 topdressing applications and subsequent traffic were repeated on the same experimental treatments.  Response variables included percent living ground cover (0.0-100%) and Clegg turf shear tester strength.  Results collected following the fall traffic period in 2008 and 2009 determined that 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.  Regarding the different sand-based material utilized in this research all material provided comparable living ground cover and turf shear tester strength with the exception of a poorly-graded sand, which produced the lowest turf shear tester strength in 2008.