‘Rolling has never resulted in soil compaction’

Thomas Nikolai, PhD, the ‘doctor of green speed’, is a senior turfgrass academic specialist based at Michigan State University. His research specialisms include golf course putting green mechanical and cultural practices and turfgrass health. Here, he discusses common myths in the industry and the benefits of rolling.

Dr Nikolai, you’ve been a leading figure in turf research for many years. Could you share a bit about your background in the industry? Do you play golf or have experience as a greenkeeper, or has your journey been primarily research-focused?

I started playing golf at the age of nine, then after high school I worked in a factory for a couple of years longing to work outside. I decided to work on a golf course and never really thought I’d be in the business this long. Fact is, I was trying to find myself and I accomplished that on the golf course.

I worked on a golf course from 1980 to 1992. For the first three years I worked with the Lilac brothers, twins who were both in their 70s. I was the only other person on the crew besides them, which meant I had a lot to do. I went from that experience to working at Oakland Hills CC [OHCC] hosting the 1985 US Open on the South Course while we were putting in a new irrigation system on the North Course. With the Lilacs I learned how much you had to cut and pinch for every penny and contrasted that at OHCC where we were donated any piece of equipment we wanted because we were hosting the US Open. After that I was an assistant superintendent and finally superintendent for years before I just sort of fell into research. The fortunate part of working on and managing golf courses with extreme differences in budgets allowed me to understand the endgame for what research was intended to do from an applied standpoint taking into consideration customer satisfaction. Most of my research has been focused on golf courses so it’s almost like I’ve never left.

There’s still a lingering belief among some in the industry that rolling leads to compaction, which you’ve addressed in your research. What do you think greenkeepers are missing out on by not embracing rolling as part of their regular maintenance routine?

I have been performing rolling research since 1994 and rolling has never resulted in soil compaction. Now let’s get logical, most greens are constructed with a sand base and even if not, most are top-dressed with sand on a consistent basis. It’s simply not possible to create compaction on sand. I’m a soil scientist, by training, and in the soil you have something called macropores, which are large pores, and micropores, which are smaller pores. Micropores hold more water and macropores hold more air and thus promote drainage. Research has not resulted in an increase in compaction, however, there have been small decreases in macropores and a subsequent gain in micropores which improves water-holding potential. Now, for the sake of argument, let’s assume rolling creates compaction, yet research proves it decreases several of the most prevalent turfgrass disease, localised dry spot, weed and even insect encroachment, then so be it, because that would mean compaction results in more benefits, including customer satisfaction, than any feared negatives. I have only been researching this for over 30 years though, so what do I know?

From a business perspective, player satisfaction is key to retaining memberships and increasing course usage. How would you describe the importance of rolling in enhancing the playing experience, and how do you see it impacting the game from a golfer’s standpoint?

Rolling golf greens, a minimum of every other day to a maximum of two times per day, enhances the golfer’s experience by providing much better playing conditions. Golfers desire firm smooth surfaces that result in truer putts that roll consistently. Rolling does this not only by allowing the greenkeeper to hit a target green speed for their membership, but it also minimizes disease, moss, and localized dry spots which mean increased possibility of making long putts by minimizing imperfections that can deflected.

You’ve mentioned that rolling increases microbial growth and moisture retention in the soil. From an economic standpoint, what benefits can golf courses expect by fostering a healthier microbial ecosystem?

I know it sounds odd, but mowing is the mechanical practice that makes the turfgrass plant struggle and become increasingly susceptible to stress. Fine fescue wants to grow to be a foot tall and creeping bentgrass three feet, but greenkeepers mow them at heights in the neighbourhood of an eighth of an inch which is why they are trained professionals. It seems counterintuitive, but research makes clear that rolling promotes better health in the plant and increases customer satisfaction. Fact is, during times of drought or heat stress, rolling daily and mowing every other day results in healthier turf while maintaining a golf course target green range. Rolling is a sustainable best management practice because it keeps multiple pests at bay, retains moisture, all while increasing customer satisfaction.

Do you think rolling could be considered a one-stop solution to achieving greener and more cost-effective greenkeeping practices? How does Tru-Turf’s technology contribute to this goal?

When putting surfaces are rolled regularly, disease is decreased and water-holding capacity increased. If you put those two together that makes it sustainable. I started working with Tru-Turf around the year 2000, and out of all the roller companies I have worked with they are doing the most continuous research. Tru-Turf has consistently made strides to improve their product, which they certainly have. Tru-Turf are also great at getting the message out about how their product works. They are in the industry to support research for the benefit of their product and their customers.

Image by Eric Galbraith: Plots with the number 1 (right hand side of image) have been double rolled daily on weekdays since late February (unless snow was on them) and those with the number 2 are not rolled. Notice rolled plots have a darker green colour, significantly less dollar spot, no moss and are firmer yet hold more moisture and result in faster green speed

For golf courses, making a decision to invest in new equipment is always weighed against long-term benefits. How would you explain the financial payoff of rolling — particularly with high-quality equipment like Tru-Turf rollers — in terms of reduced labour, healthier turf and overall maintenance savings through more rolling and less mowing?

If your course is on a regular rolling regime, and green speed measurements are taken knowing a target range to maximise customer satisfaction, you will not have to mow as often. Mowing is the most labour intensive and costly mechanical practice because mowers have heights of cut checked and tweaked daily, require their blades to be sharpened regularly for a perfect cut, must have their bedknife changed at a frequency synonymous with changing a razor blade, and they must be meticulously cleaned after each use. None of that is necessary, except rinsing off the rollers, with a roller. If you’re in an area where there’s a heavy dollar spot problem, you might find you can delay spraying, or even skip a spray, because rolling is so great at decreasing the amount of a disease outbreak. Research has also shown that rolling decreases moss and weeds all while retaining more moisture in the rootzone. Greenkeepers that use a TDR regularly have a known moisture content they know they must syringe or irrigate to. Rolling maximises the amount of water applied. Research indicates rolling maximises irrigation inputs not just on greens but on fairways as well.

Tru-Turf have been in the research business for a long time and research is how you keep making a product better as well as giving knowledge to the industry as a whole. One of the nicest things about a Tru-Turf roller is the fact that it doesn’t have an independent trailer. The roller can move from green to green on its own. Oddly enough, twice this week I’ve met with superintendents who are going to buy a Tru-Turf roller because of the ease of transporting from green to green.

For more information, visit www.truturf.com