T U R F TA L K
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By Mike Goatley, Ph.D., Turfgrass Specialist, Virginia Tech
s a graduate student at Virginia Tech in the mid-to-late 1980s, I was taken aback by the emphasis placed on fall fertility research trials on bermudagrass that I helped conduct for Dick Schmidt. Most of these trials emphasized late growing-season nitrogen applications, and this went against everything I had previously learned about preparing bermudagrass for the approaching winter months. Bermudagrass is a very photoresponsive grass, and earlier
research many years ago indicated just how quickly the morphology and physiology of bermudagrass begins to change as daylength shortens, even in the middle of summer. Have you ever noticed the increased tendency for most bermudagrasses to scalp during the late summer/early fall period? This is due to a change in its growth habit. Shorter days and cooler temperatures are Mother Nature’s way of providing the environmental signals that prompt bermudagrass to begin
preparing for the winter months. A major part of this survival mechanism is the dormancy period when plant growth and development is essentially arrested until warmer temperatures and longer daylengths arrive the next season. If this dormancy period is such an important survival tool, would not the survivability of bermudagrass be negatively affected by reducing the length of the dormancy period (i.e., extending the growing season of the grass)?
[Editor’s Note: This research-study article originally ran in the July/August 2004 issue of the Virginia Turfgrass Journal. The study’s results may be equally helpful, however, to turf managers in Tennessee and surrounding areas.]
This article highlights research that Dr. Goatley has conducted over the past 20 years, research that focuses on extending the growing season of bermudagrass by way of either late-season fertilization or the use of turf blankets. It is being presented from the perspective of sportsfield management, but the principles apply to all segments of the turf industry. Photo #1: Bermudagrass color response to late-season N applications. 18
TENNESSEE TURFGRASS
AUGUST/SEPTEMBER 2004
Email TTA at: tnturfgrassassn@aol.com