Help for heading off summer stress
When it comes to managing turf under stress, it helps if a superintendent can wear more than one hat.
Eager members ignorant of the ways of science often are guilty of pressuring superintendents into producing playing conditions that defy allowable limits defined by current climatic conditions. In response, superintendents must try to convince golfers that there is a reason they should consider mowing less frequently in favor of slightly higher heights of cut during those times when daytime temperatures and humidity soar and overnight lows offer little in the way of relief.
"You really have to be part scientist and part salesman," said Lane Tredway, Ph.D., technical representative for Syngenta and former turfgrass pathologist at North Carolina State University.
"You have to have the ability to communicate to people with varying levels of knowledge and expertise, and sometimes less expertise than they think they have. You have to be able to convince them of what you need to do and why you need to do it, which is for the betterment of their golf course. Sometimes, golfers and members think the superintendent wants to do things a certain way because it makes his life easier. But it is for the long-term health and quality of the golf course."
What many golfers do not understand, Tredway says, is that ensuring quality playing surfaces throughout the season cannot be accomplished by throwing caution to the wind and mowing cool-season turf to heights of cut lower than one-eighth inch during an ongoing summer heat wave.
"It is a year-round endeavor. What a superintendent does in September and October has a direct impact on turf quality the next May, June, July and August," Tredway said. "Managing turf is a lot like a person: You can't run a marathon without training and preparing in advance. That includes everything: fertilization, irrigation, cultivation, preventive fungicide programs, everything, and for 12 months a year."
Still, golfers often get the best of well-intentioned superintendents, coercing them into ridiculously low mowing heights throughout the summer, often with predictable outcomes.
Every time he offers advice about managing turf under heat stress, Rob Golembiewski, Ph.D., admits to feeling somewhat like a broken record.
Each year, he finds himself explaining over and over basic practices such as controlling entry and exit points on greens and the need to avoid aggressive agronomic practices during times of high heat.
"Sometimes, you feel like you're giving the same old basic advice that everyone already has," said Golembiewski of Bayer Environmental Science. "But year after year you see the same mismanagement that brings about these stresses. And guys lose their jobs because of it.
"The superintendent decides he is going to give (members) the tournament that they want. He starts to lose turf and then tries to get someone to help him. He loses greens, the club fires the superintendent and brings in someone else, then he goes through the same thing. It's a vicious cycle of unrealistic expectations."
The cycle is so recurrent that PACE Turfgrass, the San Diego-based consulting firm led by the husband-and-wife team Wendy Gelernter, Ph.D., and Larry Stowell, Ph.D., re-released one of its Youtube videos from 2010 aimed at golfers that explains why turfgrass struggles during summer.
In the video, Gelernter cites university research to explain to golfers how low mowing heights and too much traffic coupled with excessive heat, humidity can be devastating to cool-season turf.
Gelernter explains how heat stress strikes the invisible rootzone first before becoming evident in the leaves of the turf plant. By then, she states, it almost always is too late to salvage the grass.
"The plant's ability to conduct photosynthesis is greatly reduced because of mowing, and it begins to use up the carbohydrate reserves that it built up in spring," Golembiewski said. "If that continues long enough, the plant exhausts its energy reserves to the point where it has nothing left to counteract that stress, and at that point you start to lose turf almost overnight.
"So many golfers get caught up in speed, then the superintendent ends up losing the plant."
Golembiewski suggests incorporating a program of less mowing and more rolling to reduce stress on the plant. The yeoman's work on rolling research on bentgrass has been conducted at Michigan State. A recent peer-reviewed study out of Oregon State, which Golembiewski was involved in there, examines the effects of similar programs on annual bluegrass.
"So much research has been done on rolling and the stressful impact of mowing," he said. "Any time you can incorporate rolling vs. mowing you're definitely going to reduce stress on turfgrass."
Golembiewski also suggests skipping that clean-up pass when the thermometer is mostly red.
"Going around and around is more likely to result in turf loss in those areas," he said. "Forget about that. Few golfers are putting from the fringe, and if they are it's not life-or-death."
To stem the effects of potential heat stress, Tredway suggests superintendents consider using greens-cooling fans, pay closer attention to water management and take advantage of some of the new chemical technologies on the market, including those that tout plant-health benefits, such as Syngenta's Daconil Action, Bayer's StressGard line, BASF's Intrinsic portfolio as well as Civitas.
Fans help cool the turf canopy a few precious degrees and also help circulate air movement, preventing a layer of humid air from hanging over the turf that inhibits the transpiration process that leads to heat stress in turf.
"In my opinion," Tredway said, "fans are the no. 1 innovation over the last 20 years. They make such a huge difference. It is the No. 1 thing a superintendent can do to maintain high-quality bentgrass greens throughout the summer."
Maintaining proper soil moisture can help prevent stress caused by a profile that is too dry or too wet. Tredway recommends diving greens into sixths and taking multiple soil moisture measurements in each segment.
"The idea is when going into hot, humid weather to maintain a proper balance of air and water in the soil profile so the roots can function," he said. "They'll die back rapidly if its too hot wet. If it's too hot and dry, you end up with wilt and drought stress."
And when in doubt, put on that salesman's cap and try to explain to golfers why it is important to give the greens a break from normal agronomic practices and mowing schedules during the hottest times of the summer.
"It is easier to explain why greens have to be slower for a week or two," Golembiewski said, "that it is to have to explain that you have to shut down a green because of dead turf."
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