Using Sand Topdressing to Improve Native Soil Athletic Field Wear Tolerance and Surface Stability.

Researchers have determined that drain tile installation and subsequent sand topdressing applications can be used to improve the drainage characteristics of a native soil athletic field.  However, if cumulative topdressing rates far exceed root system development, surface stability will be compromised.  The objectives of this research were to evaluate the effects of cumulative sand topdressing and summer traffic on the fall wear tolerance and stability of a 90% Poa pratensis L. – 10% Lolium perenne L. mixture established on a sandy loam soil [A horizon of a Colwood series (fine-loamy, mixed, active, mesic Typic Endoaquoll)].  To explore these objectives an RCBD, with three replications, was seeded on May 29, 2007, in East Lansing, MI.  Main effects included cumulative sand topdressing applications and summer traffic.  Topdressing applications consisted of a well-graded sand (90% sand – 10% silt/clay) applied 0, 2, 4, 6 and 8 times within a 5 week period, July 11 – August 15, 2007, at a rate of 9.8 kg m^-2 (0.6 cm depth).  Summer traffic was applied once weekly throughout the topdressing periods using the Cady Traffic Simulator, and compared to a control that did not receive summer traffic.  Fall traffic was applied to all treatments twice weekly throughout the month of October.  In 2008 topdressing applications and simultaneous summer traffic, followed by fall traffic as described above, were repeated on the same experimental treatments.  In the first year only, summer traffic was detrimental to fall turfgrass cover.  In the second year cumulative topdressing, regardless of rate, increased turfgrass cover in comparison to the control.  Results obtained in both years determined that 2 topdressing applications per year, applied within a 5 week period, provided the greatest overall Clegg turf shear tester strength (Nm), while 6 and 8 applications per year, applied within a 5 week period, were detrimental to shear strength.