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Sports Turf: the Low-down, the Issues, the Future

By Pamela Sherratt and Dr. John Street, Dept. of Hort. and Crop Science, Ohio State University




Synthetic turf fields are being installed at high schools, collegiate and pro stadiums across the U.S. A study conducted at the Connecticut Agricultural Experimental Station evaluated the crumb rubber used as an infill material in synthetic turf surfaces and often in children’s play areas. Preliminary results have indicated that potentially harmful gases are volatilized and that water leached from the rubber contains elements such as lead.
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The term “sports turf” refers to the management of turf for sports other than golf. Sports turf managers maintain playing surfaces such as football fields, soccer fields, lacrosse, field hockey and so forth.

The majority of sports surfaces in the U.S. (and the world, for that matter) are geared toward young athletes, either in schools or at the parks and recreational level. The next group of athletes that use sports turf surfaces would be at the club, collegiate, and professional levels. As a representative example, in Columbus alone, the public school system includes 17 high schools, each with football, soccer, baseball and practices fields. There are also several recreational turf fields and collegiate/professional stadiums.

Basically, the U.S. loves to play and watch sports, which equates to thousands of playing surfaces!






Collegiate and pro stadiums tend to have “sand-based” playing surfaces where the growing medium contains 85-90 percent sand, with the rest organic material. Sand-based fields present challenges different to native soil fields. The drainage capability of sand is high, but the big issue is stability. Sand fields can be reinforced by adding 10-20 percent silt and clay to the growing medium. This finer soil binds the sand particles together, however, that reduces drainage capabilities. A rigorous program of coring, topdressing, judicious water management and possible use of rain covers is needed.


Native Soils

The large majority of sports fields are built on native soils, which are typically referred to as “fine” soils that contain moderate amounts of silt and clay.

Native soils produce great playing surfaces when they are dry, but can become muddy and lose structure when wet. Turf managers looking after native soil fields concentrate all of their efforts on improving the drainage capabilities of the soil by constructing fields with a raised center or “crown” and by carrying out aeration/compaction relief techniques and applying materials like sand or calcined clay to improve the soil texture. Native soil fields can typically host 70-100 events a year, less if there are rain games, more if weather conditions are favorable during the game and if there is a budget in place to maintain the field properly (topdress, fertilize, over-seed, irrigate, core, etc.)






One option of reinforcing a sand field is the cap it with a big roll of soil sod cut 1.5-2 inches thick and typically 48-in. wide by 30 ft. long. Each roll weighs around 3,000 lbs. This provides an instant playing surface, but this surface drains worse than a native soil field. Anytime a finer-textured layer of soil overlays a coarser textured material, the upper fine-textured layer will not drain until it is saturated or maybe even ponded. Field managers that introduce soil onto sand spend years trying to dilute the upper layer by coring and topdressing.


“Sand-Based” Playing Surfaces

The “higher level” collegiate and pro stadiums tend to have “sand-based” playing surfaces, which means the growing medium typically contains 85-90 percent sand, with the rest organic material. Sand-based fields present challenges different to native soil fields. The drainage capability of sand is high, with water infiltration rates of up to 20 inches per hour but the big issue in sand-based field management is stability. Reinforcing sand fields can be done in a variety of ways:

Reinforcing Sand-Based Surfaces Options

One option is to add 10-20 percent silt and clay to the growing medium. The finer textured soil acts as a packing material, binding the sand particles together. The problem with introducing finer textured material is the chance that the drainage capabilities will be reduced, possibly as low as 4-6 inches per hour. In essence, drainage and stability become mutually exclusive. A rigorous program of coring, topdressing, judicious water management and possible use of rain covers is needed for these types of fields because the soil is far more prone to compaction and poor drainage than a sand field.

A second option is to cap off the sand field with a thick-cut, big roll soil sod.

Sod is cut 1.5-2 inches thick and typically 48 inches wide by 30-ft. long. Each roll of sod weighs around 3,000 lbs. The advantage is that they provide an instant playing surface, which is why this procedure is sometimes done mid-season as a “game saver.” The disadvantage is that, when wet, the surface drains worse than a native soil field. The laws of soil physics have shown us that anytime a finer textured layer of soil overlays a coarser textured material underneath, the upper fine-textured layer will not drain until it is saturated, or maybe even ponded. Field managers that introduce soil onto sand spend years trying to dilute the upper layer by coring and topdressing.

The final option is to introduce a synthetic stabilizer, usually made of polypropylene. They come in many forms: as fibers mixed with the sand (Fibresand, Loksand), as small grids mixed with the sand (Netlon), as fibers sown into the sand (DD Grassmaster), or as carpet (Motz TS2). The advantage of a sand stabilizer is they can be used with natural grass to create a “hybrid” system. Thus, the athlete gets to play on natural grass but the surface is stabilized by a synthetic product. Stabilizer products are very popular in Europe, particularly in England where the soccer players want natural grass but many games are played in inclement weather.






Another option to reinforce a sand field is via a synthetic stabilizer, usually made of polypropylene. synthetic stabilizers come as fibers mixed with the sand (Fibresand, Loksand), as small grids mixed with the sand (Netlon), as fibers sown into the sand (DD Grassmaster), or as carpet (Motz TS2), which is the case here at the Great American Ballpark. The advantage of this sand stabilizer is that it can be used with natural grass to create a “hybrid” system. The athletes gets to play on natural grass but the surface is stabilized by a synthetic product. This option is popular in Europe, particularly in England, where the soccer players want natural grass but many games are played in inclement weather.


As we said previously, sand is the material of choice in the construction and surface management of sports turf and golf turf management. It offers numerous advantages, such as organic matter dilution, improved water infiltration rates, and better surface levels. Years of research has shown us that it has to be the “right” sand in terms of size, uniformity and shape and there are several sand suppliers in each state that can meet these criteria. One of the areas we are trying to understand more about at Ohio State is sand topdressing applications before and during the playing season.

Because sand is an abrasive material, it can injure the grass and cause loss of verdure (leaf tissue) if the sports turf manager is not careful about applications.

Our goal is to answer these questions:

  • How soon before a game should topdressing be applied?
  • At what depth should the topdressing be applied?
  • Should the field ever be brushed or rolled following a sand application?

Preliminary results would suggest that topdressings should take place outside of the playing season, to give the grass time to recover from any abrasive injury. This is especially important if the topdressing is applied thicker than 1/8 inch. Another way of introducing sand onto the field is to install “sand slits”. These sand channels significantly improve surface drainage.






Sand is the material of choice in the construction and surface management of sports turf. It offers organic matter dilution, improved water infiltration rates and better surface levels, but it has to be the proper size. As sand is an abrasive it can injure grass and cause loss of leaf tissue if the sports turf manager is not careful about applications. Preliminary test results suggest topdressings should take place outside of the playing season to give the grass time to recover from any abrasive injury, especially if applied thicker than 1/8 inch. “Sand sliting” (pictured) significantly improves surface drainage.


Mobile Lighting Systems

Two European companies have designed mobile lighting systems for stadiums with shade problems. SGL and MLR produce portable light rigs that extend the growing period of grass, particularly helpful for stadiums with high roofs and in locations where winter light quality is poor and day lengths are short. The light racks are used in stadiums like Parken in Denmark and Arsenal and Aston Villa in the UK. Ohio State will be conducting research with the MLR Lite system in 2008 and we’ll be showcasing our results on our website.

“Most athletes want to play on natural grass and the sports turf industry needs to step up and support the research needed to come up with field construction types and management systems for sand-based fields.” —The authors

Perennial Ryegrass and Fungal Diseases

Turfgrass breeders have been making huge strides on the disease tolerance of perennial ryegrass, which is a relief for the sports turf industry where so much ryegrass seed is used during the playing season. Perennial ryegrass is used all over the U.S. – either as the main grass on a cool-season field or to overseed dormant Bermudagrass. It has several advantages, the main one being that it is quick to establish. It can be played on six weeks after seeding.

Unfortunately, it has one big disadvantage in that is is susceptible to many devastating fungal diseases. The breeding work that has taken place is a huge stride forward for turf managers using perennial ryegrass. In particular, there are now cultivars that show increased tolerance to the “big boys” of diseases: gray leaf spot, pythium, brown patch and dollar spot.






Perennial ryegrass is used all over the U.S., either as the main grass on a cool-season field or to overseed dormant Bermudagrass. It can be played on six weeks after seeding, but is susceptible to many devastating fungal diseases, like this grey leaf spot on a soccer field. There are now cultivars with increased tolerance to gray leaf spot, pythium, brown patch and dollar spot.


Synthetic Surfaces

While natural grass continues to be the playing surface of choice for most athletes, including the NFL and MLS, synthetic surfaces play a role in the sports turf industry. Synthetic turf fields, sometimes referred to as “infill” or “turf” fields have been installed at high schools, collegiate and pro stadiums across the U.S. for many reasons. Most notably, synthetic fields offer teams a place to play in locations where inclement weather is a problem. In some instances, excessive field use has also resulted in poor playing conditions and administrators see synthetic turf as a means to play on the fields 24-7. There are several types of synthetic surfaces on the market and several companies that do the installation. The national Sports Turf Managers Association (stma.org) has produced a short booklet aimed at people considering a synthetics surface and it gives information on selection, construction and maintenance of a surface. Dr. Andy McNitt from Penn State also has a lot of useful information on his website.

A study conducted at the Connecticut Agricultural Experimental Station evaluated the crumb rubber (recycled tires) used as an infill material in synthetic turf surfaces and often used in children’s play areas. Preliminary results have indicated that potentially harmful gases are volatilized and that water leached from the rubber contains elements such as lead. Obviously there will be a lot more information coming out about this – both from environmental groups and the synthetic turf industry. As the report has received press there has been a knock-on effect, particularly on the East Coast where local politicians have talked about these issues as part of their election platform. More independent research is needed in this area before conclusions can be drawn.

Next on the agenda for synthetics? I believe Sportexe is bringing out a fiber-optic surface “Turf TV” in the future!






Most sports fields are built on native soils, often referred to as “fine” soils, that contain moderate amounts of silt and clay. Native soils produce great playing surfaces when they are dry, but can become muddy and lose structure when wet. Turf managers of native soil fields concentrate their efforts on improving drainage by constructing fields with a raised center, carrying out aeration/compaction relief techniques, and applying sand or calcined clay to improve soil texture.


Staph Infections?

The possibility of our young athletes getting a staph infection is a worrying thought. The question is, can athletes pick up a staph infection from a synthetic or natural grass playing surface? Research undertaken on these surfaces is indicating “no.” During a recent study by Dr. Andy McNitt at Penn State University, Staphylococcus aureus was not found either on synthetic fibers or in the natural grass system, It was however found on towels and other devices used by athletes. Dr. McNitt also suggested that a higher incidence of staph might occur on synthetic turf, not because it harbors the disease, but that athletes tend to get more abrasive wounds and are therefore more prone to infection from other sources. Ref: cropsoil.psu.edu/mcnitt/infill.cfm.

The Future of Sports Turf Management

Most athletes want to play on natural grass and the sports turf industry needs to step up and support the research needed to come up with field construction types and management systems for sand-based fields. It was the advent of artificial turf in the 1960s that led to the surge in sports turf research out of England’s Sports Turf Research Institute (STRI.co.uk). What the STRI has done for professional soccer for the last 40 years needs to be repeated in the U.S. for collegiate and professional football.

We still have a lot to learn about the new synthetic surfaces and their management. There are still questions that need answering on these types of surfaces and how they affect athlete health and playability. Unfortunately, it is such a huge and complicated task to compare natural and artificial turf that I don’t think we’ll ever truly be able to answer the one big question: “Which causes more injury?” I went to a talk a couple of years ago by a medical doctor from Australia that had looked at ACL injuries in conjunction with field surface type (synthetic versus natural, differing grass types). More of this type of research is needed but there aren’t too many medical people out there doing turf research, and there are even less turf people out there that know much about medicine!

About the authors: Pamela J. Sherratt, MS, from England, is a sports turf specialist and has been in the sports turf industry for 17 years. She has a B.S. from University of Central Lancashire in England, an M.S. from Ohio State University, and is working on her PhD at Ohio State University.

Dr. John R. Street, PhD, received his undergraduate B.S. from California State University and his M.S. and PhD degrees from Ohio State University. His research focus is sports turf fertility and culture and surface stability.

For turf information, visit buckeyeturf.osu.edu.


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March 25, 2019, 12:12 pm PDT

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