Researchers Look for Best Grass Varieties for Minnesota Roadsides

University of Minnesota researches are studying which grass varieties hold up best on the state?EUR??,,????'?????< Photo: MnDaily.com

If you listen to Garrison Keillor’s “Lake Wobegon” report on his weekend Prairie Home Companion radio show on NPR, you know Minnesota weather in his fictional Minnesota hometown is always part of the conversation.

Of course it snows a fair bit in Minnesota. Municipalities use salt on the roads to facilitate snow and ice removal. Road salts, of course, are not only tough on roads, but also on any vegetation on the roadsides.

“We always had a problem with salt-tolerant sod on our roadsides,” reports Brett Troyer, erosion and stormwater management engineer for the Minnesota Department of Transportation (MnDOT). MnDOT approached the University of Minnesota’s Department of Horticultural Science in 2009 with the problem.

Eric Watkins, assistant professor of horticultural science at the University of Minnesota, received a four-year $175,000 grant from the Local Road Research Board in Roseville, Minn. to research salt-tolerant turf grass mixes. The study began in 2010.

As roadside construction is a major inconvenience for home and business owners, “We want to make sure we get it right the first time,” says Roseville city engineer Deb Bloom.

The university research should help MnDOT do their jobs more efficiently and save money by decreasing the number of replanting projects.

Josh Friell, a graduate research assistant in charge of the day-to-day research for the project reports the researchers have already discovered more efficient turf mixes than MnDOT uses.

Hundreds of mixes are tested indoor and on roadside plots. Researchers do much of their research in greenhouses on the St. Paul campus, and along Larpenteur Avenue.

The goal is to find mixes that survive the winter cold and salt exposure, and the heat and humidity of the summer. Researchers judge the success of the grass by how thick it remains and whether it stays green.

Indoors, researchers have designed a sample pallet holding hundreds of mixes of turfgrass. They plant the grass in pots of sand, supported by a nutrient solution containing everything the turf needs to survive, Friell explains. The nutrient solution is altered by increasing the sodium content, and then each pot of grass is studied for its reaction.

Outdoors, four plot locations are planted with the same turf grass mixes. These are measured in the spring and fall for reactions to weather conditions throughout the year. Friell said it’s ideal the indoor and outdoor results match, leaving them with the most salt-tolerant mix.

Friell explained that each species of grass contains several varieties, which change the characteristics of each grass mix. For example, the alkaligrass, as you would expect, performed well for salt tolerance, but performed terribly for most other conditions.

So far, Friell said, variations of fine fescue have been the most tolerant mixes overall.

The first year’s work has shown which seeds worked best, Troyer said. The second year of research will focus on which mixes create the most efficient balance.