AgBioResearch

Since the early days of civilization, humanity has been playing sports. And for as long as there have been sports, there has been a concurrent need to manage and maintain the spaces that host them. From the ancient tracks and arenas of Olympia to the numerous stadiums, golf courses and athletic fields that dot the cities of the modern world, the expertise, skill and passion of the people dedicated to preserving and improving these important cultural centers have long played a significant, if often unsung, role. Michigan State University (MSU) boasts a long history of assisting these professionals beginning in the 1880s, when MSU botanist W.J. Beal conducted turfgrass species evaluation studies at the Michigan Agricultural Experiment Station, now MSU AgBioResearch. Since then, researchers — especially those of the MSU turfgrass program — have been offering innovative solutions to the everchanging needs and challenges faced by the sports industry.

Kevin Frank, MSU AgBioResearch and Extension turf specialist and associate professor in the Department of Plant, Soil and Microbial Sciences, said one of the first significant scientists in the field in more recent times was James Beard, who began his career in academia at MSU and is professor emeritus of turfgrass science at Texas A&M. His seminal work, “Turfgrass Science and Culture,” laid the foundation upon which many turf managers and scientists around the country were educated.

“Dr. Beard quite literally wrote the textbook on turfgrass in 1973, and we still use that book today,” Frank said. “Starting with his early work, MSU has had a reputation for doing research that is very applicable to the industry.”

A few years later, in 1979, MSU and the Michigan Turfgrass Foundation broke ground on the Robert Hancock Turfgrass Research Center in East Lansing, which continues as the home for leading-edge turfgrass science.

A little sand goes a long way

One of the most fundamental truths of plant management of any kind, whether in agriculture, landscaping or turfgrass, is plants’ need for water. As with so many things, however, too much of a good thing can be disastrous. When a field floods, the soil can eventually be strangled by the substance that brings plants to life. Too much water excludes oxygen from the soil, creating an anaerobic environment in which roots cannot survive. This can be particularly devastating for athletic fields and golf courses, whose function depends entirely on maintenance of a healthy, uniform field of turfgrass.

To promote proper drainage, turf managers often use a significant percentage of sand in the soil mixtures on which their fields grow. Sand particles are larger than those of clay or silt — the other two primary soil ingredients — resulting in a looser structure through which water can escape. Muddy soil compacts under pressure, inhibiting the growth of any plants that call it home; sand does not. In addition to its drainage benefits, sand is also slightly more malleable, reducing the impact on players’ bodies and, therefore, decreasing the risk of injury.

Trey Rogers, MSU AgBioResearch turfgrass scientist and professor in the Department of Plant, Soil and Microbial Sciences, said that researchers have known for a long time that sand equates to better athletic performance.

“MSU Spartan Stadium is a great example of that. It can rain 3 inches and players on the field won’t have a speck of mud on them,” Rogers said. “The beauty of sand is that it drains well and it keeps turf growing.”

Building a sand-based field from the ground up, however, comes with a hefty price — starting at $500,000 upwards to $1 million. This presents a serious obstacle to institutions such as middle and high schools, particularly in rural areas. Many fields in Michigan and across the country are saddled with native soils with poor drainage, which can result in extensive damage.

In the early 2000s, some schools began tearing out their fields, covering the topsoil with 6 inches of sand and thenreturfing them to give the fields a fresh, healthy start for less than the cost of anew all-sand facility. Still, the process remained too expensive for many, and many others lacked the expertise to establish a new field.

“These were all problems that reared their heads every rainy Friday night in October, because the fields would get soaked and torn up by games and would remain in a sort of ruined state for the rest of the year and into the next spring,” Rogers explained. “Big high schools could afford to install an artificial field, but the small ones didn’t even have that option.”

A new, more affordable solution was needed. Rogers and graduate student Alec Kowalewski began developing a way to give schools the stability and drainage advantages of sand fields without exorbitant costs. A former football player from a small high school in Michigan, Kowalewski was the perfect candidate to help Rogers tackle the issue. Their solution was as innovative and elegant as it was simple. Called build-up sand capping, this technique involves adding sand little by little across the surface of the field. The blades of grass grow up through the sand, and after multiple treatments, several inches of sand are in place. And it can all be done for about $150,000, a mere fraction of the cost of a new sand-based field.

“The beauty is that there’s no difference, from a performance perspective, between a sand-capped field and one that’s pure sand,” Rogers said. “This is finally a true alternative that’s viable for places with a smaller budget, and we still get calls about doing it today.”

From Pontiac to Beijing

When the Pontiac Silverdome was chosen as the first indoor stadium to host a WorldCup soccer match, its field managers were faced with a problem. The World Cup  organizers wanted teams to compete on a field of live, not artificial, turfgrass. The issue: the building’s reinforced canvas fabric roof allowed only 8 percent of natural sunlight to pass through it and reach the surface below. The problem: without better access to natural light, the field simply would not survive for the duration of the tournament.

“The organizers knew they were going to need help, so they asked us to develop a turf system that could be used indoors,” said James Crum, MSU AgBioResearch soil scientist and professor in the Department of Plant, Soil and Microbial Sciences. “It was something nobody had ever really tried before at that scale, although there has been much more since.”

In the summer of 1992, Rogers and Crum began development of a portable athletic field, one that could spend the majority of its time outdoors, basking in natural sunlight and soaking up rain, be moved inside the stadium for play and then returned outdoors. They didn’t want the tenure under the dome to take its toll. On paper, it seemed rather simple, but challenges soon emerged.

Rogers and his team built a research dome similar in structure and material to the Silverdome near the Hancock Turfgrass Research Center on MSU’s East Lansing campus. There, they tested various combinations of turfgrass species, fertility practices and irrigation techniques to produce a turf perfectly tailored to the conditions of the World Cup. Few of these factors proved as significant to the novelfield’s viability as the soil in which it was planted, however.

“This was the most extensive study on indoor turfgrass that had been conducted at that point,” Crum explained. “James Beard had done the only related work in New Orleans, but for that project he had simply brought sod indoors and studied it. Our project required a more in-depth focus.”

It became apparent early on that the soil requirements of an athletic field were much different than those of other turfgrass areas. The soil of putting greens, for example, has a nearly 100 percent sand
composition to allow for rapid drainage in the event of rain, but an athletic field for a sport such as soccer requires greater durability.

Working with Rogers, Crum spent the summer and fall of 1992 developing a soil mixture that struck the necessary balance between drainage and strength. The smaller particles of clay and silt packed together tightly, increasing the overall strength of the soil, while the large proportion of sand still allowed water to drain quickly. Comprising 80 percent sand, 10 percent native soil and 10 percent peat, the new mixture offered excellent drainage while boasting improved durability.

“We realized that a sports field would require a bit more silt and clay to hold water a little better and improve its strength and stability,” Crum said. “It’s very important you get the right variety of particle sizes in the soil. Finding the right mixture of sand, clay and silt is right at the heart of everything we do in turfgrass research.”

While Crum developed the soil, a concurrent effort was under way to develop a system of modular containers to house what would become the new World Cup field. Built at a factory in Pontiac very near the Silverdome, the hexagonal modules were assembled in the stadium’s parking lot in the spring of 1993. The field was configured by filling the modules with the tailored soil mixture and covering it with several varieties of Kentucky bluegrass that had been shipped on refrigerated trucks from southern California especially for the occasion. Then came the first true test of the new system.\\

“They wanted to have a trial run before the World Cup because this had never been tried before and they wanted to make sure it worked,” Crum said.

On June 19, 1993, the Silverdome hosted the final game of the U.S. Cup, in which Germany and England competed for the championship. As more than 62,000 fans filled the stands to watch the next installment of a storied soccer rivalry, the world’s first portable athletic field system experienced its opening match. This was the first time in the history of professional sports that a field of live turf had been used indoors, but it certainly would not be the last.

Almost exactly one year after its first success, the new field system was brought indoors a second time to fulfill its original purpose: hosting World Cup soccer. Teams from the United States, Switzerland, Romania, Sweden, Russia and Brazil competed in four matches, along with numerous practices, before crowds of more than 70,000 and hundreds of thousands more watching on television.

A company called GreenTech formed to commercialize the technology. With continuing guidance from Rogers and Crum, GreenTech built fields for stadiums around the country, including Giants Stadium in New Jersey and the tennis courts of Wimbledon.

An obvious advantage of a portable field is that it can be established elsewhere and moved into its stadium later. During renovations following the 2001 football season, preparations were made to outfit MSU’s own Spartan Stadium with just such a field. It was prebuilt across campus with the modules transported into the stadium in time for the start of the 2002 football season.

“Spartan Stadium had an artificial field for many years prior,” Crum said. “The renovations gave us an opportunity to make some changes, and the university administration took advantage of that to have a high-quality live field installed."

The team took the opportunity to reevaluate the soil mixture they had developed to maximize its beneficial attributes. Rogers and Crum, along with then-MSU graduate student Jason Henderson, examined the soil’s agronomic properties, such as drainage, and also looked at it from an engineering perspective that took into account the weight it would bear and the stress of athletic competition it would experience. From these intensive observations, the team produced an optimal mixture with slightly more sand and less silt and clay.

The field remains in Spartan Stadium to this day, removed only once for resodding because of damage following a performance by the band U2 in 2011.

The World Cup and subsequent early successes of the portable athletic field were but a foretaste of the innovation’s future. As preparations were beginning for the 2004 Olympic Games in Athens, Greece, organizers found themselves facing a new problem. As part of the opening ceremonies, the Olympic stadium would be flooded with water. Such an inundation would surely kill any turfgrass, making it next to impossible for the games to begin the following day.

“They wanted to fill the basin of the stadium with water, drain it and then on the next day be able to play on a mature, well-established, superior-quality athletic field,” Crum said. “And that’s exactly what our program was able to give them.”

Like its World Cup predecessor, the field was established in modules several months before the start of the games under Rogers and Crum’s supervision using the same optimized soil mixture developed for Spartan Stadium. Less than 36 hours after the opening ceremonies, the new field was moved into the stadium and the games of the 28th Olympiad could begin.

The work of Rogers and Crum did not go unnoticed. When the summer Olympics moved to Beijing for the 2008 games, their expertise was again requested. The challenge this time was that the opening ceremonies would feature so many performers that the field would be left trampled and ruined. As in Athens, the portable athletic field proved to be the answer. The field was held outside the stadium until after the ceremonies, then moved in for the games.

The advent of portable athletic field technology proved to be the answer to a number of significant challenges. The modules themselves, however, would mean little without the right soil inside. The skill and expertise of MSU turfgrass researchers allowed a novel concept to become a true innovation.

“The thing you have to remember about the portable fields is that they are a solution to a problem,” Rogers explained. “It allowed events like the Olympics to have these elaborate ceremonies and afterward have a field of a quality nobody could be embarrassed about.”

As portable athletic fields have proliferated around the country and the world, the mark of MSU turfgrass research has been unmistakable.

“It’s quite exciting to know that something you were dedicated to and worked on has continued to be used, to grow and evolve,” Crum said. “The whole experience has been just incredibly rewarding.”

The 17-year leach

Like water, nitrogen is one of the musthaves of plants. It promotes rapid, robust growth, and nitrogen fertilizer is one of the staples of management on farms, home lawns, athletic fields and golf courses alike. Plants can only take up this resource at a finite rate, however, and once more turf managers are discovering the dangers of having too much of a good thing.

“Nitrogen is king, in terms of the resources a plant needs,” said Frank, who has continued a 17-year-long experiment on the patterns and effects of nitrogen leaching in soil that began two years before his arrival at MSU in 2000. “Mother Nature supplies the light, the water and the oxygen, but we often have to add nitrogen. Especially in home lawns, that’s what people see the greatest response to.”

When nitrogen is added to soil, it becomes available for plants to take up and use. Excess nitrogen, however, has the potential to leach from the soil into the groundwater and other segments of the ecosystem, where its presence is less beneficial. Frank’s long-term study on this subject has yielded important insights into how turfgrass utilizes nitrogen and, by extension, how it can best be applied to maximize its benefits and limit its negative impacts.

The Hancock Turfgrass Research Center has played host to the nitrogen leaching experiment since its inception. There, a series of lysimeters — large, open-topped metal cylinders with a spigot near the base — have been filled with 4 feet of soil covered with a layer of turfgrass. The soil is treated with varying levels of nitrogen, and, as water runs through the lysimeter, sensors in the spigot measure the nutrients flowing out, representing what would be leached into the environment in a real-world scenario. The results are surprising and illustrate the importance of long-term research.

During the initial years of the project, when the turfgrass was newly planted, little to no nitrogen was observed to leach out of the lysimeters — the turfgrass was utilizing virtually all of it as it grew and established itself. As time wore on, however, and the turfgrass matured, Frank’s team was surprised to discover that significantly more of the nutrient was leaching through the soil.

“Everything changes as it ages, which was kind of a revelation,” Frank explained. “After a decade or so, we saw that nitrogen starts to leach into the water system, which can then contaminate water sources and pose a health risk to people, particularly those living in rural areas.”

Frank is now working to develop ways for turf managers and homeowners to limit their nitrogen use without negatively affecting their grass. His team has already reduced their nitrogen use from 5 pounds to 4 pounds per season without seeing a significant change in turfgrass health.

“From a practical standpoint, you build a home in the suburbs, say, and for the first 10 years while the soil is developing and building up organic matter, you fertilize a lot,” Frank said. “Twenty years later, however, your soil has changed and now you don’t have to fertilize as much to get the same result. That’s what we’re exploring now.”

Battling soil-borne disease

One of the most persistent concerns in turfgrass management is the ever-present threat of disease. Whether fungal or bacterial, diseases can ruin the pristine look of a playing field or golf course, degrading not only its appearance but also its capability for hosting games. MSU AgBioResearch plant pathologist Joe Vargas recently confronted a new disease that has been taking a toll on golf courses along the East Coast.

First appearing four years ago, the disease, now known as bacterial etiolation, came to Vargas’s attention when a North Carolina golf course superintendent sent his lab a sample of turfgrass that had been infected by it. The disease targeted creeping bentgrass, one of the most common types of turfgrass used in putting greens. The North Carolina course was far from the only one affected, however — numerous other golf courses from New England to Texas began replacing their creeping bentgrass greens with other species, such as Bermuda grass, largely because they had no effective means to fight this mysterious pathogen.

Etiolation is a condition in which grasses begin to turn yellow and grow sickly, spindly blades that reach above the normal turf level. Turf managers were concerned that this new wave of etiolation sweeping their courses was being caused by a plant growth regulator, a chemical used to check plant growth and keep golf course putting greens uniformly short and easy to maintain.

“It didn’t make sense to me that something that suppresses growth would cause it to spiral out of control,” said Vargas, a professor in the Department of Plant, Soil and Microbial Sciences. “So we looked at it more closely to try to isolate the pathogen.”

Vargas and graduate student Paul Giordano discovered that the disease was caused not by a chemical or fungus but by a bacterium, Acidovorax avenae. Other bacteria in the same genus had been known to attack agricultural crops such as wheat, rice and watermelons, but this was clearly something different.

Using a scanning electron microscope, Vargas and Giordano discovered that the bacterium resided in the soil and moved into the plants’ xylem cells, the cells responsible for conducting water from the roots to the foliage, cutting them off from needed water and resulting in their sickly, stringy appearance as they attempted to outgrow the bacterium. Furthermore, they found that, as temperatures and soil acidity rose, the activity of the bacterium worsened.

“It’s most devastating in regions with warm temperatures,” Vargas explained. “It was also pronounced in areas of New England, where we found they were fertilizing with ammonium sulfate, which is an acidifying fertilizer.”

There are no registered turfgrass antibiotics, and none of those used in agriculture were shown to be effective in stopping Acidovorax avenae. Vargas has, however, found that simply reducing the use of acidifying fertilizers, either alone or in combination with certain plant growth regulators, can significantly decrease the incidence of the disease.

“We now know how we can at least restrict the environment in which the pathogen thrives,” Vargas said. “Golf courses that previously had no recourse other than replacing their greens entirely now have some alternatives at their disposal.”

Making sure the grass is always greener

The research conducted by the MSU turfgrass team serves the MSU land-grant tradition by providing the industry with important practical insight and resources. By establishing relationships with turf managers, the team has been able to help them solve problems as they arise.

“Turfgrass has always been a part of my life,” Rogers said. “It’s a place where a perfectionist can toil and never get bored. You build something, then it gets worn and torn, and you keep working at it. We understand that, and our students understand that.”

From a homeowner’s lawn to the Olympic Games, the scope and scale of the issues that the turfgrass team tackles are as varied as the people they help. They operate on every level to ensure that turfgrass, and the soil it calls home, is functioning at the highest level.