Regional Optimization of Roadside Turfgrass Seed Mixtures

Project summary:

Roadsides in Minnesota account for nearly 100,000 hectares of established vegetation. This vegetation is responsible for preventing erosion and for keeping nutrients and contaminants from reaching ground and surface waters. Current MnDOT specifications for roadside turfgrasses suggest statewide planting of mixtures that are grouped into five broad categories such as low-maintenance turf and high-maintenance turf. The objective of this research was to identify turfgrasses that possess traits necessary to survive in the harsh roadside environments found throughout Minnesota. The research investigated the impacts of possibly the three most limiting environmental conditions (heat, salt, and ice cover) on multiple cultivars from up to 15 individual turfgrass species. Salt stress screening revealed several species with good levels of adaptation including alkaligrass and tall fescue. In the heat stress trial, the reserach found cultivars and selections of Canada bluegrass, tall fescue, Kentucky bluegrass, strong creeping red fescue and slender creeping red fescue were among the top performers. Finally, in ice cover screening, tall fescue and Chewings fescue did well; however, these results did not correlate well with the researchers' typical field observations. For each of these stresses, the research identified top-performing cultivars that will be evaluated in field studies with the goal of identifying optimized mixtures for stakeholders in Minnesota.