New Putting Green Irrigation System Saves Water

Golf has a water problem.

Each year, golf courses around the U.S. spend billions of dollars to keep fairways and putting greens lush and thriving. Depending on where a golf course is located, many courses around the world spend around $1 million each year on irrigation. Meanwhile, more and more golf courses face irrigation restrictions and water rationing.

Putting greens are especially difficult to keep perfectly watered. The grass is grown on a soil mixture that’s predominantly sand, allowing it to drain excess water during rain events. But because sand doesn’t hold water, the grass must be irrigated daily.

That’s a problem that MSU’s Hancock Turfgrass Research Center is working to solve. Thom Nikolai, MSU senior academic specialist, and his team are one year into a cutting edge putting green irrigation project.

Nikolai, known worldwide as the “Doctor of Green Speed, and Michael Rabe, an MSU graduate student and assistant farm manager, are testing a subground irrigation system called a Capillary Hydroponic System. After one year of collecting data, the hydroponic system used 60 percent less water compared to Variable Depth Rootzones.

Their research is funded by the U.S. Golf Association, the Canadian Turf Research Foundation and the Michigan Turfgrass Foundation.

“These institutions are not funding the study due to the rising cost of irrigation,” Nikolai said. “It’s because they are serious about promoting sustainable practices, which includes minimizing water inputs.”

A man working on hydroponics for a golf course

Michael Rabe, MSU graduate student and assistant farm manager at the Hancock Turfgrass Research Center, checks the pump that moves water back and forth in the putting green subground irrigation system.

State of the art facility

For decades, the Hancock Turfgrass Research Center has built a reputation as a premier facility. It’s attracted worldwide recognition for its cultural and mechanical practices to increase customer satisfaction while decreasing inputs. Program alumni have gone on to manage world-famous golf courses and sports facilities, including the Detroit Tigers’ Comerica Park. Last year, the facility signed a contract with FIFA to build the turf for the 2026 World Cup.

MSU’s reputation caught the eye of Martin Sternberg, inventor and founder of Swedish company Capillary Flow. Sternberg was already well-known in the golf world, and in 2018, Golf Inc. Magazine called him one of the most influential people in golf course construction.

When Sternberg and Nikolai ran into each other at a conference, Sternberg told him about his idea for a subground irrigation system for golf courses. Since he wasn’t a researcher, he knew he needed help. He’d heard Nikolai speak at a conference 20 years earlier, an experience he told Nikolai changed the course of his golf course management career. Sternberg flew to Lansing to check out MSU’s turf facility. Right away, he was adamant. Hancock Turfgrass Research Center was the best place to test out his hydroponic system and get it ready for public use.

“He could have built this test site in New Mexico or Arizona, but all he had to do was take one look at MSU and say, we’re doing this here,” Nikolai said. “This project is just a natural progression of what’s been going on here for decades.”

Capillary Flow spent about $400,000 to build a square of six test greens on the Hancock facility’s 65 acres – three with hydroponic irrigation, three with Variable Depth Rootzones (VDR). VDR greens are the invention of Nikolais’ mentor, MSU Emeritus Dr. P.E. Rieke. Research earlier this century at the turfgrass center showed VDR had more uniform moisture retention compared to standard USGA rootzones.

For the hydroponic systems, the sand under the green is contained in a waterproof cavity, as if it’s resting in a bathtub. That tub is split in half and connected to a pump that floods one half of the tub with water. Then, the water flows back and forth between the halves so that the water doesn’t become stagnant and breed diseases. A pump can also push water out of the tub in case it’s oversaturated with rain.

Golf’s water problem

The first goal was building a subground watering system that worked – something Nikolai said golf courses have tried to do since the dawn of the 20^th century. Most golf courses still rely on sprinklers to keep their fairways and greens irrigated and ready for play.

According to a Golf Course Superintendents Association of America 2013 survey, U.S. golf courses used an estimated 1.859 million acre-feet of water—about 605 billion gallons per year. While this number is high, it’s down from the reported 2.312 million acre-feet reported in a 2005 report. And courses in drought-prone areas, like Arizona and California, require more irrigation than more temperate regions. Some courses are forced to buy water to keep their greens irrigated.

“The golf industry recognizes that water is key to the survival of the game,” Nikolai said. “It’s all hands on deck to find ways to save water.”

Michael Rabe, MSU graduate student and assistant farm manager at the Hancock Turfgrass Research Center, shows the site where two irrigation systems for putting greens are being compared – subground and above ground.

Golf courses have looked to conservation methods such as irrigation scheduling, soil amendments, using recycled water and keeping turf drier than they might have in the past. Some have tried drip irrigation—a method that works well for landscaping plants, but not quite as well for grass, Nikolai said.

While others have tried to build underground irrigation systems, the result was always stagnant water that can lead to disease and pests. Sternberg’s system of flowing the water back and forth was a game changer. The theory is that when the water is sucked out of one side, oxygen is pulled into the water. Then, as water is pushed up from the bottom of the tank, it pushes carbon dioxide out.

No difference in playability

Rabe uses specific data points to compare the three hydroponic greens to the three traditional greens. Standing amid the grass, there’s no difference among them. Each is perfectly green and firm, with the soil rising and falling slightly just as a real course would. But Rabe doesn’t only rely on his eyes.

First, he checks the flow meters from each irrigation system, measuring how much water was used in each. Then, he checks the green’s playability using a tool called a Stimpmeter, an angled track that releases a golf ball at a certain velocity so that you can measure how far the ball rolls. Rabe also tests the firmness of the green using a TruFirm tester, which drops a weight from a specific height and generates a firmness reading.

After one year, the results are already promising. Rabe’s data showed no difference in playability between the hydroponic greens and the traditional. Meanwhile, the hydroponic greens using 60 percent less water than the traditional sprinkler system. He expects the hydroponic system to save even more water in the coming years. The goal in the first year was simply to figure out how to make the system work. Now, armed with more data, he said the water savings could be as much as 90 percent.

Nikolai suspects research will continue on the site for at least the next 20 years. He’s looking forward to finding ways to store rainwater and reduce the need for pesticides by using beneficial bacteria to keep the plants healthy.

The longevity of research will also allow MSU turfgrass researchers like Rabe to best inform end users who install and use the system on golf courses and other athletic field sites. While the system will save golf courses money on irrigation, Nikolai is more concerned with conserving the planet’s precious water resources.

Story by Bethany Mauger