Fields of Green
Smart Strategies & New Ideas in Sports Field Maintenance
If you have to maintain the lawn at your residence, you know what a challenge and time commitment it can be to keep that yard looking healthy and pristine. And if you have children who put that lawn through the paces on a regular basis then you know how heavy use only increases that challenge. So imagine how demanding the task must be for those who manage and maintain sports fields, which typically see a lot of use in all types of weather and oftentimes have to be game-ready between events with very little recovery time.
"Maintaining parks and municipal fields is a great challenge with a lot of variables," said James Bergdoll, director of parks maintenance for the City of Chattanooga's Department of Parks & Outdoors in Tennessee. "We have a small athletic field maintenance team that focuses on a certain group of higher-profile and city-operated fields, while the rest are maintained through user groups, volunteers and contractors."
Bergdoll pointed out that when user groups are responsible for maintenance, they often tend to manage field use better. "Unfortunately, they sometimes don't have the resources or expertise to properly perform needed maintenance, so we try to help out where we're needed through contractors like mowing, aerification, topdressing, laser grading, etc."
Parks and municipal fields can be an extra big challenge since so many people use them and they are used for a variety of activities. "Different sports have different high-concentrated-wear areas, so managing that on multi-use fields is certainly a challenge," said Bergdoll. "Being able to rotate and move field layouts helps a great deal. Additional aeration and/or topdressing of wear areas, spot fertilization and resting when possible are other strategies for combating high-use wear."
Iowa State University (ISU) has a robust program for both men's and women's sports, including a football team that is consistently a serious contender in the Big 12 conference. Josh Tvrdik is director of turf and grounds for the ISU Athletics Department and he addressed some strategies for getting a field game-ready when there's heavy use and little resting time. "Our first line of defense for a quick turnaround is having an aggressive fertilizer program. Giving the plant what it needs to heal and recover in a quick amount of time is crucial. We also overseed the entire field before each game so the cleats from the athletes are cultivating the seed into the ground and we have constant germination throughout the season."
Overseeding is the process of applying seed to an existing field in order to improve turf density and help it recover from frequent use, and it's an important tool in the arsenal for promoting healthy grass. Research has shown that the best grass to use for overseeding is perennial ryegrass, even if a different species was used originally. "There's a school of thought with cool-season grasses to overseed high-wear areas such as goal mouths and player position areas," explained Bergdoll. "The player's cleats will 'dimple' the seeds into the soil for good seed-to-soil contact. You are also building a seed bank where grass seed will germinate and fill in wear areas while allowing play to continue during a season."
Climate makes a big difference as far as which type of turfgrass grows best and how to maintain it, as each variety has its own requirements. For instance, Bermuda grass performs well in the southern United States, while Kentucky bluegrass is more common in northern areas. "At Iowa State we really push Kentucky bluegrass," said Tvrdik. "It's a dark, dense grass that stripes up nice and recovers well in our climate. And with new cultivars of bluegrass coming out, we are able to push it harder and expect more out of it than what we could in the past."
Keeping that grass mowed is obviously a critical task, and in many cases, athletic fields should be mowed at least twice per week, starting in early spring. No more than one-third of the leaf blade should be removed during mowing, which explains the need for frequent mowing. Some NFL teams mow three to five times per week, but of course most athletic fields don't have the maintenance budget for that. Therefore it's important to research how high the grass can get without causing damage to it when it's cut. Mower heights must also be considered, as this can affect turf roots, turf density and wear tolerance.
"When determining height of cut (HOC), there are a few items to consider: grass type, climate/season, sport and amount/level of usage," said Bergdoll. "Certain grasses perform better when cut at (certain) heights, and then you have to consider ball roll and playability." A higher cut of grass might slow ball roll while a lower cut will increase the speed. "These considerations should be taken when determining the grass type when planting a field."
When it comes to mowing equipment, there are many options and considerations, and while today's zero-turn mowers cover a lot of ground, Bergdoll explained that they might not be the best option for higher-profile athletic fields. Some manufacturers build mowers specifically for sports fields, which might be designed to stand grass up for a better cut and offer a wider width of cut, more cutting units or blades and rollers for striping. "Whatever piece of equipment is used, ideally you assign a specific unit for fields and/or certain grass types to decrease the chances of contaminating the athletic fields with weeds or other grass species," said Bergdoll, adding that blade sharpening is also important. "Sharp blades produce a clean cut that not only looks better but is better for the health of the plant itself."
Tvrdik explained that there are two basic types of blades for grass cutting: conventional blades and reel blades. "We use the conventional style like what's on your mower at home due to the ease of being able to sharpen them when needed. Reel blades are more commonly used on very short grass like a putting green. Since we cut most of our grass at one and one-quarter inches, we're able to get away without having reel mowers."
As far as fertilization, Tvrdik said they perform annual soil tests on all their fields to put together a fertilizer program that caters to what the grass needs. "We shoot to apply between four to seven pounds of nitrogen a year depending on what the soil test results are. We also spoon feed our turf; every two weeks we're applying small amounts of micro/macro nutrients to the turf to make sure it stays happy and healthy. We apply fungicides throughout the season to prevent any diseases from attacking the turf."
Tvrdik also said they core aerate their fields five to six times a year to prevent organic buildup in the sand-based root zone. "This also allows for great drainage and promotes a strong and healthy root system so our athletes have good footing. After we core aerate, we cover the field in sand to allow air and water movement through the profile."
Tvrdik also stressed the importance of drainage for keeping fields playable during inclement weather. "All our game fields are built on a USGA sand profile, which means we have 12 inches of sand on top of two to four inches of an intermediate layer, which sits on top of 12 to 14 inches of pea gravel with drainage pipes running throughout the field. Our football fields are all crowned to have water shed off them to keep the center of the field as dry as possible. Most native soil fields will retain water for hours after a heavy rain where having a sand-based system will allow for quick drainage."
Bergdoll agreed that poorly drained fields have a negative impact on use and increased maintenance input. "Ideally having some type of internal drainage system is preferred, but at the very least having the field graded properly to ensure surface runoff is very important."
On the flipside, Bergdoll said some of their fields have irrigation systems, and stressed that water and moisture management are key pieces of maintaining natural grass surfaces. "However, breeders continue to develop new varieties of turfgrasses that require less water, and we try to incorporate those when appropriate to help reduce that input and be more sustainable."
Tvrdik reported that all their fields have subsurface irrigation. "We monitor moisture levels at two- to three-inch depths to make sure we aren't overwatering or underwatering. The moisture-level reading is crucial in telling us how much water to apply or how long to hold off. All our scheduled irrigation times are based off of moisture-level readings."
In addition to the nine natural turf fields at ISU, there are also two synthetic fields that are maintained by the Athletics Department. "Our maintenance practices for synthetic would include dragging, grooming and disinfecting the turf. We try to manicure both synthetic fields at least twice a month," said Tvrdik, who added that they impact-test their indoor football field and soccer game field once a year to ensure they're safe to play on. "Once we see the reading, we can then make a decision on whether to add more crumb rubber to soften it up or remove rubber to firm up the surface. One benefit to synthetic is that when a team needs to practice in inclement weather, they have a place to do so without ruining their game or practice field."
There seems to be a perception among some that synthetic fields are maintenance-free, and while there are currently no synthetic fields in Chattanooga's parks, Bergdoll said this is simply not the case. "Based on experience, I can tell you that most park administrators, city officials and user-group leaders don't understand that artificial fields require maintenance. Typical high-wear areas such as goal mouths and batter's boxes require a lot of maintenance just like a natural surface. If artificial fields are not routinely maintained, they become unsafe for use, which is hard to understand if you don't have a professional on staff monitoring conditions."
It should also be pointed out that like natural turf fields, synthetic fields also require superior drainage systems.
Darren Gill, senior vice president of marketing and innovation for an international synthetic turf manufacturer with 25,000 installations globally, said it's important to understand that high-performance synthetic turf sports fields are not maintenance-free, and went on to describe working with field managers who've "helped us create and refine our maintenance recommendations and guidelines over the past few decades. In addition, we have a tremendous field care division that can assist clients in situations where they don't have the resources to perform their own maintenance. We also leverage technology… to assist field managers in understanding what type of maintenance should be done on their fields and at what frequency.
"Our multi-faceted approach includes standard guidance for brushing, aerating, raking and sweeping along with new options for those who want to sanitize their fields," Gill continued. "We've worked to simplify the field maintenance procedure for our clients and make their lives as easy as possible. Our design thinking approach keeps maintainers in mind throughout the product development process."
When it comes to baseball and softball fields, there are added maintenance challenges, including infields vs. outfields, pitcher's mounds, batter's boxes and bull pens. "Depending on the amount of use, the skinned areas often require daily maintenance to keep low areas from developing, edge or lip buildup, weed control etc.," said Bergdoll. "One thing to note is that there has been some really great advancements in materials in the past five to 10 years. I recommend anyone to do some research to see what's available in their area as far as materials. There has been a strong push on better-performing soil mixes in low-maintenance situations such as parks and recreation fields."
Tvrdik's team maintains one softball field, and he explained that keeping the infield moisture content just right tends to be the most challenging aspect. "We flood the infield a couple times a day and let it dry out before a practice so that it doesn't play too hard or too soft. After practice and games, we patch the mounds and homeplate with clay and tamp the holes to keep everything filled in and flat. When it rains, we pull out the infield tarp to prevent washouts and muddy playing conditions."
New technologies continue to aid the turfgrass industry, and Tvrdik said these can prove to be huge timesavers. "We now use a GPS chemical sprayer to control where we are applying chemicals to prevent any overlapping and waste. This saves us money, helps the environment and teaches us to be better turf managers. We use a tool called a TDR to monitor the moisture level of all our playing surfaces. This stops us from guessing on how much water to apply with our irrigation systems and from wasting water."
Bergdoll said they're fortunate to have companies in their industry that understand their challenges and work to develop new products and technologies to help with efficiency. "Because as demand goes up, our capacity and resources do not, in most cases. Some of the new technology that (I've) been watching closely has been robotics and artificial intelligence. With a labor shortage, we may have to rely more on this technology to help us do our jobs."
In fact, it's becoming increasingly common for municipalities and facilities to utilize outside firms for help, particularly with specialized maintenance tasks, according to Bergdoll. "It certainly is for us because we have such a small team and limited capacity. With the cost of equipment and labor shortages, using outside firms often makes more sense from a budgetary standpoint, but not always from a scheduling aspect. There are pros and cons to everything so you have to weigh your options to make sure it makes sense for your operation." RM