Developing Salt-Tolerant Sod Mixtures for Use as Roadside Turf in Minnesota
Joshua Friell, Eric Watkins, Brian Horgan
Report no. MnDOT 2014-46
Failure of roadside grass installations due to high levels of road salt is a common occurrence in Minnesota. Several species that are not currently included in the MnDOT recommendations for these sites have performed well in low-input turfgrass evaluations in Minnesota and warranted evaluation for salt tolerance and suitability for roadside environments. The goal of this project was to develop a recommended mixture or a set of mixtures that provide salt-tolerant sod for roadsides. In the first part of this research, cultivars of cool-season turfgrass were assessed for their ability to establish and survive on roadsides in Minnesota. Concurrently, these grasses were evaluated in a hydroponic system in the greenhouse for salinity tolerance. Together, these studies identified several species and cultivars that were promising for use on Minnesota roadsides. These top-performing grasses were then evaluated in a series of mixtures in three research trials: (1) a roadside evaluation at two locations in Minnesota; (2) a sod strength trial planted at two locations in Minnesota; and (3) an acute drought evaluation utilizing an automated rainout shelter. From these results, we identified species that should be components of a salt-tolerant turfgrass mixture for use on roadsides in Minnesota. Mixtures that included high proportions of fine fescues, especially hard fescue and slender creeping red fescue, performed the best in our trials indicating that these species should be utilized in MnDOT recommendations for turf grown on roadsides.