Golf Course Management

APR 2014

Golf Course Management magazine is dedicated to advancing the golf course superintendent profession and helping GCSAA members achieve career success.

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50 GOLF COURSE MANAGEMENT 04.14 of years I had observed cutworms, along with their unmistakable chewing damage, on my plots that coincided with increased bird feed - ing. Therefore, I hypothesized that the birds were going after the cutworms. The three years this happened I counted bird-beak holes in the turfgrass before mowing/rolling. Plots rolled three times per week had signifcantly fewer bird-beak holes (and therefore fewer cut - worms). Interestingly enough, the decrease in bird-beak holes was between 55 percent and 60 percent in each of the years, which seems pretty consistent. I now feel comfortable stating that I think rolling decreases cutworm activity, but in all truth I did not count cutworms, so I can - not say it with 100 percent confdence. I'll leave that up to you until a turfgrass entomologist performs a conclusive study. 4. Improved topdressing incorporation In 2006 Michigan State University per - formed a lightweight roller/sand incorpora- tion study on creeping bentgrass putting green plots. Treatments included control plots that were never topdressed with sand, topdressed plots with the sand brushed in when dry, and plots that were brushed and then received a sin - gle pass with the True-Surface vibratory roller. The day after topdressing, the plots were mowed with a walk-behind mower, the debris was collected into buckets and put into paper bags that were placed into an oven at 104 F to boil off water. Then the debris was poured into a bucket of water, in which the sand sank while the clippings foated. Clippings were collected with a net and the sand was poured onto a very fne screen, returned to the oven and weighed. The result was approximately 40 percent less topdressing sand was collected in the buckets when plots were rolled after brushing (Figure 2). These plots also had a faster green speed several days after topdressing and decreased or - ganic matter content at the end of the season. John Sorochan, Ph.D., performed a similar study on bermudagrass greens at the University of Tennessee and reported an 80 percent de - crease in the amount of sand after a single pass with the True-Surface vibratory roller. To my knowledge, no university research study has tested whether non-vibratory rollers increase sand incorporation after topdressing. 3. Decreased dollar spot In 1995 I noticed that research greens rolled three times per week had less dollar spot than greens that were not rolled. None of the data was statistically signifcant, and I was certain I would never make a similar observation. The following year, the rolled plots on my research greens had signifcantly less disease each time a dollar spot outbreak occurred. To say I was sur - prised would be an understatement. Since then I have made similar observations year after year in my lightweight rolling studies. Additionally, in 2011 Paul Giordano, a Michigan State grad - uate student, reported that increasing the fre- quency of rolling signifcantly decreased the in- cidence of dollar spot. The obvious question is, "Why does rolling decrease dollar spot?" The answer is lengthy and a bit elusive, and heck, this is just a top-10 list. The important fact is that regular use of lightweight rolling does de - crease dollar spot. 2. It's the economy (rolling/mowing frequency programs) I published the results of my dollar spot observations in a scientifc journal in 2001, and understandably many of my peers seemed skeptical. In 2002, I gave a presentation on the subject at the GCSAA Education Conference in Orlando, and several roller companies were so delighted that they have continued to fund my lightweight rolling research to date. Sup - port from those companies (and the Michi- gan Turfgrass Foundation) has allowed us to study the effects of various rolling/mowing fre - quency programs over the years, including the three listed below. • Alternating daily mowing and rolling. In 2004 Michigan State initiated the frst mowing/rolling frequency study by com - paring mowing every day with alternating mowing and rolling on a daily basis. On Sand collected after topdressing Collected (grams) 400 350 300 250 200 150 100 50 0 Check Broom Broom + vibratory roller Research greens that are rolled frequently show signifcant- ly less dollar spot disease. Figure 2. In 2006, creeping bentgrass putting green plots received one of three treatments: never topdressed with sand (check); topdressed with sand with the sand brushed in dry (broom); or topdressed with sand with the sand brushed in, followed by rolling with a vibratory roller (broom + vibratory roller). The graph shows the amount of sand collected in a mower bucket the day after treatment. 044-055_April14_roll.indd 50 3/18/14 2:50 PM

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