Low inputs, little maintenance and the ability to withstand wear and tear – that’s what turfgrass managers want today.
There is plenty to consider when it comes to natural grass turf for sports stadiums. As you tune into your favorite college football or NFL team this weekend, take a look at the stadium. Does it have shade or no shade? Is it in a warm climate or a cool climate? Is there a retractable roof?
Whether it’s Kentucky blue grass or a turf-type tall fescue, all these factors and more must be taken into consideration when it comes to nurturing natural grass turf in sports stadiums.
Turfgrass managers are demanding new cultivars because they need surfaces that are durable and can recover well. They need surfaces that are low maintenance, requiring fewer inputs and less water. They need varieties that can handle stress — be it athletes, weather or pests and diseases.
Bred to Handle Stress
Evaluating how the turf wears is key to finding a suitable mix for your surface. “We want a cultivar with adequate wear, but also good seed yield,” says Leah Brilman, director of research and technical services for Seed Research of Oregon — a business unit of DLF Pickseed.
The durability of Bermudagrass has made it a favorite of NFL teams, which is put to the test weekly during the season. In a recent poll by Sports Illustrated, seven of the top 10 fields in the NFL were in southern climates, and all but two had some variety of Bermudagrass.
Brilman says turfgrass managers are not only looking at the lower maintenance Kentucky bluegrass, but also ryegrass and turf-type fescues for sports fields. “Especially when you get down to younger kids’ sports fields, we are seeing much more use of turf-type tall fescues,” she says, adding that Kentucky bluegrass holds up well, has excellent sod strength and produces an adequate amount of seed.
Brilman explains that her team, in partnership with the Alliance for Low-Input Sustainable Turf (A-LIST) has done a lot of work with tall fescues and selections under stress.
Many of today’s stadiums are less than ideal for sun exposure. To manage these factors, stadiums in the southern United States have tried hearty, warm weather strains like Paspalum and Zoysia.
Edzard van Santen, an Auburn University professor in the College of Agriculture, says they’re breeding bentgrass for the southern transition zone. And to the east, turfgrass scientists at the University of Georgia are working on Zoysias for sports fields and Paspalum for watering issues.
Turfgrass managers have to battle many stressors, such as cold and heat. Working to make turf withstand cold, drought and heat tolerance is key, whether that is spring dead spot in Bermudagrass or brown patch in turf-style fall fescues.
When it comes to the weather, Brilman says things have gotten more and more unpredictable.
Van Santen adds that it’s not so much climactic instability that turfgrass managers need to be wary of, but what New York Times columnist Thomas Friedman calls, “global climactic weirdness.”
The effects of the, “weirdness depend on location and factors such as precipitation,” he explains. “Throw in oscillation patterns such as El Nino Southern Oscillation and you have a real mess.”
During the past 20 years, van Santen says a few patterns have emerged. “When I started at Auburn, you hardly ever saw Argentine bahiagrass (a forage species) in northern Alabama, whereas today it is frequently observed,” he says. “Thus, warm season grasses are used much farther north than 20 years ago. We have warm season sports turf as far north as West Lafayette, Ind.”
Changing weather patterns have also expanded the growing season in many regions, which changes pest pressures. As an example, van Santen says fall armyworms appear earlier nowadays and sometimes a month earlier than in the past. “This affects other turf management options such as the application of pre-emergence herbicides,” he says, noting that disease and pest resistance are paramount.
According to van Santen and his colleagues, Dave Han, Extension turf specialist and associate professor, and Elisabeth Guertal, turfgrass and nutrient management professor, it’s difficult — and getting harder — to manage the growing tide of emerging pests and diseases.
Resistance and new pesticides are contributing factors, and while industry is creating new compounds and formulations to combat these problems, the process is long and arduous.
Brilman agrees, “We are always looking at disease resistance.”
But as pest pressures increase, so does the need to use fewer inputs, such as insecticides and herbicides.
“We want turf that can survive with less water, herbicides and fungicides — in general, a turf that can survive with fewer inputs,” Brilman says.
Bill Kreuser, assistant professor and Extension turfgrass specialist at the University of Nebraska-Lincoln, says some school grounds across the country have banned pesticides — a trend that is likely to continue.
Kreuser shares that in the 1990s and early 2000s, new grass releases required high maintenance conditions. With good maintenance, grasses performed really well. However, he says most were not maintained at the level they needed to be.
When turfgrass isn’t maintained, Kreuser says it gets compacted and can be pretty hard, especially if it is not irrigated and fertilized properly. This is especially important when athletes hit the field, and deal with injuries, such as concussions, he explains.
Now the big thing is grasses that are able to use less water, nutrients, pesticides, etc. — all while producing a dark green color.
Regardless of region, Brilman says low maintenance turf is key, and that low-maintenance theory also applies to irrigating sports fields.
“As the water supply becomes scarcer, the ability of turf to recover from stress under a water-limiting regimen will become more important,” she says. “We’ve been doing a lot of work in that area. For instance in California, we are looking at our turf and maintaining cool season turf with less water, and assessing which ones do best under those conditions. We are also looking for ones that you can let go (dormant) and bring back up … and ones you can water at 60 percent of the evapotranspiration rate.”
While the need to use less water is always important, Kreuser says the bigger issue is the timing of application — whether that’s watering the field or applying a product,
“We shouldn’t just be putting things down based on calendar intervals,” he says. “We should be using data to make better choices about timing.”
Kreuser says some new areas researchers are looking into include supplemental grow lights that are rolled onto the field. The broader theme is plant health, he adds. “We are really trying to maximize all of the things that we can control to make plants as healthy as possible with minimal stress,” he says.
It’s a tall order, but turfgrass researchers across the country are working hard to match the right turf to the right stadium and the right products to the right situations. The campaign to improve turfgrass cultivars is endless and knows no geographical boundaries.
DLF Pickseed, through its brands — DLF, Pickseed USA, Pickseed Canada and Seed Research of Oregon — has trials not only in Oregon, but has a farm in Kentucky, Denmark, France and the Czech Republic to name a few. If they don’t have a site where they are growing their own turf, they work with the National Turfgrass Evaluation Program or a local university or sod grower to put on trials in that particular region.
Brilman says they also look at alternatives, such as tetraploid perennial ryegrasses, a turf-type intermediate rye that germinates later in the season.
“We never develop for one characteristic, always a broad range, and at end of day it still needs to produce seed,” Brilman says.