Editor's note: This post is the “Verdure” column by Beth Guertal, Ph.D., as seen in the September 2014 issue of GCM.
Several years ago, in hot and humid Auburn, Alabama, we had the pleasure of having the National Turfgrass Evaluation Program’s (NTEP) bentgrass putting green trial. Let’s just say that I think we were selected as the “really bad place to be” trial location. In that trial, there were a few velvet bentgrass cultivars, luxurious and sensual cool-season turfs that never failed to become dyspeptic and chlorotic each summer. While they may not have proven to be “the thing” for the Deep South, velvet bentgrasses are a turf of interest in Europe and other regions with a more moderate climate.
In 2009, members of Dr. John Stiers’ highly productive research program at the University of Wisconsin-Madison published a paper that evaluated velvet and creeping bentgrasses, examining the effect of nitrogen rates and mowing heights on these grasses. The objective was to examine the grasses’ utility in low-input putting greens, since velvet bentgrass is widely considered able to handle more austere conditions than creeping bentgrass.
This elegant study was simple in its approach: four bentgrass cultivars on a sand-based root zone (SR 7200 and Vesper velvet bentgrass, and Penncross and L-93 creeping bentgrass), all of which were mowed at various heights (0.25, 0.156 and 0.10 inch) [6.4, 4.0 and 2.5 millimeters]) and received two different nitrogen rates (⅓ or ½ pound nitrogen/1,000 square feet/application [48 or 146 kilograms/hectare/
year]). The nitrogen was applied as split applications from May through October (three apps for the low nitrogen rate; six apps for the high nitrogen rate; nitrogen supplied via a 21-1-10 N-P-K granular). Artificial traffic was used to simulate 21,000 rounds of golf, and the green was mowed with a reel mower six days a week. Data collection included green-up, quality, shoot density and ball roll.