March 2013

Keeping roadsides green with salt-tolerant turfgrass

Eric Watkins and his team have tested hundreds of mixes at an indoor facility.

Road salt is an important weapon for fighting ice and snow, but it also can be deadly to roadside turfgrass. After a number of failed sod installations in recent years, the Minnesota Department of Transportation turned to researchers in the Department of Horticultural Science to identify turfgrass mixes that could tolerate the salt and harsh conditions on Minnesota roadsides.

“What we see happening on these roadsides that don’t have salt-tolerant grasses is [that] public agencies are continually spending money to redo their initial project,” says Associate Professor Eric Watkins, the lead researcher. “That’s where there could not only be some environmental benefits, but also quite a bit of money to be saved by some of these municipalities and local governments.“

Under a four-year grant from the Minnesota Local Road Research Board (LRRB), the research team, including graduate research assistant Joshua Friell, has been testing hundreds of grasses and mixtures of grasses at an indoor facility and on roadside plots provided by MnDOT. The researchers have already discovered better grasses than those currently in use. The best grasses, Watkins says, are those that can survive heavy salt exposure, cold winter conditions, and hot and humid summer weather.

The ultimate goal is to develop seed mixtures that produce salt-tolerant sod. Watkins and the Minnesota Crop Improvement Association (MCIA) worked with MnDOT and the Minnesota Sod Producers Association to develop seed mixes as well as an associated sod certification program to ensure that quality sod of verified composition is delivered to buyers. Sod produced from the original seed mix they developed has been used on roadside projects the past two years, says Ben Lang, MCIA president/CEO.

Sod grown from a new seed mix that was refined using Watkins’s research findings should be available in late 2013. The new seed mix will be reviewed at the end of the year to determine whether modifications are needed. “Again, Dr. Watkins’ research will be key to making any decisions to modify the mix,” Lang says. He anticipates that sod products developed through this program will continually evolve and improve as better-suited turf seed varieties become available.

MnDOT has specified salt-tolerant sod for road and bridge projects and expects to use the new seed mix to stabilize difficult soils during the 2013 construction season, says Dwayne Stenlund of the department’s Office of Environmental Services.

Watkins’s success has attracted additional funding. In a new project approved by the LRRB in December, the researchers will create best management practices for installing and establishing salt-tolerant grasses on roadsides. In addition, Watkins, along with his team and scientists from Rutgers University and the University of Wisconsin-Madison, have launched a five-year project investigating how to develop turfgrasses that will require less water and mowing and that can remain green without fertilizers and pesticides. The project is funded by a $2.1 million grant from the U.S. Department of Agriculture.