Effect of Seeding Date on Establishment of Native Grasses

Project summary:

MnDOT has been working towards successful establishment of drought-tolerant native prairie plants along highways. In the Upper Midwest, there appears to be a critical period in mid-to-late summer when seeding of prairie species is avoided because seedlings do not mature enough to survive the winter. MnDOT recommends plantings native seed mixes April - July 10 or after September 30 (Jacobson, 1996). Understanding when to plant is crucial to successful stand establishment of prairie grasses but no studies were found on planting dates for the Upper Midwest. Our research tests seeding dates throughout the growing season. It will provide evidence on how seeding date affects the establishment of prairie grasses in Minnesota. We anticipate this project will lead to field-tested recommendations for optimum seeding dates for these native prairie species. The study runs December 1995 through June 1998. Field plots at the University of Minnesota, St. Paul Campus, will be seeded with monocultures and mixes of four native grass species: Schizachyrium scoparium. Bouteloua curtipendula, Elymus canadensis. and Bromus kalmii. During both the 1996 and 1997 growing seasons, 10 seedings will be done at 10-30 day intervals. The number of seedlings established will be counted in September 1996, June 1997, September 1997, and June 1998. We will then analyze the data and determine whether seeding date affects first year establishment and winter survival of native grasses. In addition, we will investigate whether there is correlation between establishment and temperature, rainfall, and photoperiod.