The Effects of Turf Covers and Plant Growth Regulators On Spring Growth and Quality of Kentucky Bluegrass.

Sports turf managers are often faced with the dilemma of having to provide a functional and aesthetically pleasing athletic field in the early months of spring.  Kentucky bluegrass (Poa pratensis L.) is one of the slowest species to resume active growth in the spring. Previous research has shown that short term (14-28 days) covering events of turfgrasses will promote spring greening and growth, but that the covered areas usually have a marked decline in turf quality later in the spring season. The purpose of this study was to determine if the use of plant growth regulators can control the spring surge in growth caused by short term covering and eliminate the later decline. Four cover sources were used: a white polypropylene product from Xton Inc.; a white nonwoven geotextile from Surline Turf; a woven, translucent polyethylene from Covermaster (Evergreen); and an uncovered control as whole plots.  After covers were removed, PGRs were applied as sub-plot treatments and applications were repeated every two weeks. Data were periodically collected on turfgrass color, quality, clipping yield, and shoot carbohydrate content.  Results in 2008 showed that all cover treatments had significant main effects on all measured parameters at the time of cover removal.  The best initial color/quality response was observed with the Surline white geotextile and the Evergreen polyethylene covers.  By the end of the study, there were no significant differences between the uncovered control plots and the covered plots.  PGRs had no significant effect except on clipping yield reduction.  Further investigation into the effects of cover type, PGR type and application timing were conducted in spring 2009.  Effects on color, quality, clippings, and carbohydrates for the entire experiment will be presented.