Sports Turf Selection & Maintenance
For spectators, watching a football or soccer game in rainy, snowy or muddy conditions can be quite entertaining, especially as the game wears on and the field and players are reduced to a muddy mess. But while the players can easily hit the showers, the playing field is another story, and these are the things that keep field and sports turf managers awake at night, as oftentimes they're tasked with having to get that field back to playing shape for the next event, which might be scheduled for the very next day.
Whether it's a high school or parks and rec field, or a Division One college or professional sports field, there are many considerations when it comes to sports turf selection and maintenance. "Artificial and natural grass turf have significant differences, and how your sports field performs is influenced by a variety of factors," according to Clay Schneckloth, a landscape architect at Snyder & Associates, an Iowa-based firm specializing in engineering, planning and design services.
Schneckloth's firm has worked on a number of athletic facilities in the parks and school sectors, including new designs and renovations. And while natural turf is still standard, Schneckloth is noticing more small market facilities like high schools turning to artificial turf, which is often due to the number of events they'd like to schedule. "With artificial turf, they're not having to 'rest' the field like you might have to with natural turf to allow it to recover from the activity; they can schedule activities back-to-back and not have to worry about the natural turf getting beat up or destroyed. Also, after a rain event, they're able to get back on the artificial turf much sooner than a natural turf field."
Of course, many athletes prefer natural turf, though there are certainly maintenance challenges. "A turfgrass field needs a strong root system to flourish and withstand repeated use," said Schneckloth. "And establishing a strong root system begins with the right conditions."
On projects where natural turf is preferred, Schneckloth and his colleagues focus on several aspects of athletic turf design to help fields achieve those conditions and remain game-ready.
Funding is also a big consideration, and decisions involving irrigation, drainage, maintenance and the type of soil and turf species will be affected by budget.
The level of play is also a factor—is it a local recreation field or a top college campus?—and of course, the amount of use that's anticipated for the field, since some might be used just once a week compared to others that might host multiple games on one day.
Schneckloth pointed out the importance of irrigation systems. Certain species of turf require more water than others, and sand-based soils typically need more water than native soil fields. Natural turf should be watered deeply, which makes moisture monitoring important. Of course, too much water will impact growth negatively too.
Proper drainage is critical, including surface drainage of surrounding areas. Utilizing an underground subdrain system is ideal, and conducting soil borings and analysis can also drive decisions. "Understanding the soil composition will help determine the design of the subdrain system," said Schneckloth. "It's always a good idea to include soil analysis by a geotechnical engineer. Both are a valuable component for a healthy natural turf."
For many natural turf fields built on native soil, drainage can be a big problem. But budgets might not be large enough to install a synthetic field. Another option is installing a sand-based field which involves excavating a foot or more of soil, installing drain tile, a gravel layer and a sand-based root zone. Another option is the sand cap model, which is less expensive because only a small layer of topsoil is removed from the field and replaced with a layer of specifically blended high sand-based root zone material. The turfgrass is then reestablished from seed. Installing a drain system is also necessary.
Finally, Schneckloth explained that it's important to develop a maintenance plan. "Constructing or renovating a sports field is a large capital improvement. Keeping the field in top performance shows responsibility for the investment and (means) safety for the users of the field. The maintenance plan will help guide the timing and budgets needed to properly care for the field."
Multiple Fields, Multiple Sports
The Iowa State (ISU) Cyclones boast a proud sports tradition, and their football team—which competes in the Big 12 Conference—had a standout year this past season. Adam Thoms is the assistant professor of commercial turfgrass there, helping to troubleshoot turfgrass problems for the turf managers at ISU's athletic department, who maintain nine natural grass fields and two synthetic fields.
Thoms and the athletic department shared some insights involving their work, agreeing that weather is a big challenge. "Some years it rains a lot, and it's hard to get the turfgrass roots to go deeper into the rootzone. Drier years it's actually easier because we can just add the water we need and drive the roots deeper, making a stronger playing surface," said Thoms.
Thoms explained that climate makes a big difference in which type of turfgrass grows best and how you would maintain it. "In the southern U.S. it would be bermudagrass, and more northern areas is Kentucky bluegrass. Some areas use bermudagrass overseeded with perennial ryegrass during the fall and winter months. Each turfgrass has its own requirements, but at the end of the day there's a turfgrass that performs well in every part of the United States."
Baseball and softball fields present their own challenges, with outfields and infields requiring different strategies. Dragging the infield after each use is important, varying points where you enter and exit the field and staying away from the edges. To prevent buildup around the bases, they should be removed during dragging. A regimen of mesh dragging and occasional nail dragging is recommended by groundskeepers. And dragging in the off-season can help prevent weeds and correct grade problems.
Edging is important, and rolling the field when it's moist. Daily care of high-use areas like the bullpen, home plate and pitcher's mound is important, using hand tools to pack and level clay. Laser grade the infield skin periodically if possible, and consider using a rain tarp.
Aerating the turf to loosen compaction—especially in high-traffic areas—is helpful, and those areas should be overseeded frequently. And it's better to mow more often and keep mower blades higher; you don't want to cut more than a third of the plant as that can damage cells.
At ISU they have one softball field, and the athletic department said that since their seasons are in the spring and fall, when rain and snow can be factors, weather is always a challenge. Wear is another challenge. "Typically Division One softball programs don't have a separate practice facility for their team, which means we're using our game field as a practice field. So we'll see wear spots in high-traffic areas like position spots. We repair the infield daily and tarp as needed when inclement weather approaches."
Turf managers are looking for ways to be more eco-friendly these days, and Thoms explained that this includes making an effort to use slow-release fertilizers. "This limits runoff from the fertilizer or leeching. We also don't use as much fertilizer as people think; we are only in the four pounds per 1,000 square-feet per year range." Technology also continues to play a bigger role in maintenance and sustainability. "We utilize a GPS sprayer, which allows us to limit any overspray or misapplication," said Thoms. "The sprayer has individual nozzle control so it would shut off if we drift outside of our boundaries or overlap too much. This has reduced our pesticide use. Irrigation is another one; our systems can be controlled from our phones so if there's a rain shower in the middle of the night we can shut the irrigation off without having to leave our house."
Thoms agrees that more small market venues are turning to artificial turf, with weather being one big reason. "You don't have to worry about what happens to the field if it rains or snows and you have a full day of events."
But he points out that some people believe the turf is maintenance-free, so they install it and forget it.
"The problem with this thinking is that not maintaining these fields results in a shorter life, and then you have to come up with the money to replace it. It's not like you can add $25 worth of grass seed to an area where the fibers are worn out because the field is worn out."
According to Thoms, they work on their artificial turf fields often, as they do require regular maintenance. "We are constantly checking the crumb rubber infield depth to make sure it is not migrating off the field. The fields get brushed regularly… the more the field is used, the more often you need to stand the fibers back up; if you don't stand the fibers up they will wear out prematurely. We also have to de-compact the crumb rubber, which keeps the surface hardness down."
Unlike the old days of synthetic sports turf, there are now many systems available with new innovations always on the drawing board. And there are different turf systems that are well-suited to different sports, whether that be football, soccer, baseball, lacrosse, field hockey, rugby and multi-sport fields.
Fiber, infill and backing are all considerations when choosing a turf system.
Fibers—often made from polyethylene—act as the individual grass blades. Different types include monofilament, which is designed to stand straight up, delivering natural ball-roll and ball-bounce characteristics. With slit-film systems, the fibers are fibrillated to create a net or honeycomb designed to lie over and encapsulate the infill. These are designed to be tough and absorb heavy use. Hybrid systems combine monofilament and slit-film.
Infill acts as the soil or dirt in an artificial turf system, providing a cushioning layer that absorbs impact. It plays a vital part in performance and safety. Three-layer, two-layer and low-infill systems are available. Crumb rubber—made from recycled tires—has long been the most common type of infill used. Other post-industrial recycled products are also utilized. But different options for infills are more readily available now, including sand, thermoplastics, cork, coconut peat and olive cores.
Just as with natural turf, drainage is important with artificial turf. Backing systems and the coatings applied to them can aid with drainage by being perforated or porous. Shock pad systems also help with impact protection and drainage. They're typically used under surfaces designed with less infill weight, and can help turf systems meet specific impact testing requirements. Systems utilizing organic infills are required to have a shock pad. Some are designed to be resistant to extreme weather fluctuations.
Know Your Options
Darren Gill is the senior vice president of marketing for an international manufacturer of artificial turf systems with numerous sales and operations offices across the United States. He explained that since no two fields are alike, there is no one-size-fits-all solution. "We've worked extremely hard to ensure that our comprehensive product line includes an array of products with various fiber and infill types along with underlayment options. Our consultative sales approach works to build an in-depth understanding of our customers' needs and works to propose solutions that make sense for their sports, geography and overall design goals."
Gill said their design approach keeps "maintainers" in mind, and he explained how they've worked to simplify field maintenance procedures. He related that many clients conduct standard maintenance themselves but utilize the company's service to perform advanced care.
And they've now added a program designed to elevate cleanliness standards and meet new challenges presented by the Coronavirus pandemic. "This multi-faceted approach includes our standard guidance for brushing, aerating, raking and sweeping, along with new options for those who want to sanitize their turf fields."
And while Gill's company has clients that include Mercedes-Benz Stadium, host of the Superbowl in 2019, along with many other NFL, NCAA and MLS clients, he points out that the key driver of their business and the industry has always been the high school and parks and recreation market. "These segments benefit immensely from the advantages of synthetic turf compared to natural grass, including the increase in playable hours, reduced maintenance, lack of irrigation and in the end, the lowest cost of total ownership."
Paul Adams is vice president of sales and marketing for a New Jersey-based company that launched a new artificial turf product in the United States in July of last year that was named one of the Top Sports Innovations of 2020 by Coach and Athletic Director magazine.
"The thermoplastic elastomer infill used in our system is made of recycled ocean plastic. Every field built helps remove over 1 million bottles of ocean plastic waste. The…protective pad we use in our system is composed of 100% foam," said Adams, explaining that these remnants come from many industries, thus keeping them out of the traditional waste stream. Additionally, the "woven nature of it—no polyethylene backing—allows for 100% recyclability at the end of life."
He added, "The fibers of our woven turf stand vertical, offering less rotational resistance as well as the ability to cut, pivot and turn with reduced danger." He said that their drainage system—and the lack of a backing—allows for quicker drainage, and the systems are built with a protective pad base. "Our proprietary infill is, on average, 28 degrees cooler than black rubber crumb."
Used artificial turf is expected to produce 1 to 4 million tons of waste over the next 10 years, according to Adams, who cited a Solid Waste Industry analysis. "We aim to not only elevate turf performance and player safety aspects, but awareness as well within the industry in terms of our planet's health by constantly challenging the status quo and setting new standards." RM