In the September 2014 “Up to Speed” column, I interviewed three golf course superintendents who regularly rolled their fairways. All of them had taken up the practice, in part, because research had concluded that frequent lightweight rolling on putting greens decreased the severity of the turfgrass disease dollar spot. At that time, research on fairway rolling was limited, but fortunately, several studies on the topic have been performed since that column ran. Here, I will consider results from those studies to help shed light on the practice, and to assist turf managers in making better-informed management decisions regarding fairway rolling.
In 2011, a three-year fairway-rolling study was initiated by Thomas Green, M.S., at Michigan State University (MSU). Over the course of the study, fairway rolling rarely resulted in significantly lower levels of dollar spot disease. What is pertinent, however, is that Green used a lightweight roller manufactured for use on a putting green to perform his fairway-rolling study. This is important because of the obvious differences between putting greens and fairways — most notably, fairways are mowed at a higher height of cut and have more organic matter buildup. Green concluded that using a heavier roller with greater pressure (pounds/square inch) might achieve the same benefits on a fairway as a lightweight roller does on a putting surface. This hypothesis seems sound when we recognize that Paul Giordano, Ph.D., correlated decreases in dollar spot on the putting surface with changes in microbial populations in 2010.
Given that backdrop, let’s consider research by Jay Popko, M.S., and Geunhwa Jung, Ph.D., of the University of Massachusetts Amherst. They performed 18 fairway-rolling studies over three years, using the Smithco Ultra 10 fairway roller and the Tru-Turf FR-108 unit. Significant dollar spot reduction, ranging from 20% to 60%, occurred in 15 of the 18 trials. Furthermore, Popko observed that trials initiated earlier in the growing season led to greater dollar spot reduction. Other benefits recorded from their research included quicker spring green-up, reduced clipping yields and reduced puffiness on creeping bentgrass fairways. It is noteworthy that the 100-gallon tank on the Smithco roller was empty during the experiments. Would greater reductions in dollar spot have resulted if the tank had been filled?
In 2017, a fairway-rolling study was performed at MSU with a Smithco Ultra 15 fairway roller. The roller’s 150-gallon tank was filled with water (adding 1,112 pounds) to maximize the pressure on the fairway stand. Treatments for fairways in the study included no rolling, rolling twice per week, and rolling three times per week; all of these treatments were mowed three times per week. A fourth treatment was mowed only twice each week and rolled three times per week.
The most interesting results from the first year of the study include:
- Rolling decreased the amount of clippings even on the fairways that were mowed less frequently.
- All rolled plots resulted in firmer fairway surfaces, which indicates that frequent fairway rolling may result in longer ball roll.
- As in the UMass study, the fairways had reduced puffiness and, in my opinion, looked healthier.
Unfortunately, the MSU site experienced no disease pressure in the summer of 2017.
The fairway-rolling studies reviewed here substantiate the observations of the superintendents I interviewed back in 2014: Dollar spot is decreased, and lower clipping yields mean less need to mow. As fairway-rolling studies move forward, it is important to test the effect of roller weight (pounds/square inch) on dollar spot suppression. I can assure you that MSU will be performing such a study in 2018. Until then, we’ll just have to wait to determine the significance of fairway roller weight on disease reduction.
Thomas A. Nikolai, Ph.D., the “Doctor of Green Speed,” is the turfgrass academic specialist at Michigan State University in East Lansing, Mich., and a frequent GCSAA educator.