Enhancing Stand Establishment of Switchgrass Grown as a Bioenergy Feedstock.

Economically viable production of switchgrass (Panicum virgatum L.) as a bioenergy feedstock requires successful stand establishment. Establishment can be severely hampered by grassy weed pressure and poor germination from unsuitable environmental conditions or inherent seed dormancy. A field experiment is being conducted with the 'Cave-in-Rock' cultivar at two sites at the East Lansing Field Research Facilities (42o75' N, 84o47' W) in Michigan. The objective of this study is to determine the most suitable planting date and seeding methodology to ensure successful establishment and high yields in subsequent production years. Seeding methodologies being examined are no-till drilled, conventionally drilled and conventionally tilled and planted with a dual roller (Brillion^TM) seeder. The planting dates are fall, early, mid and late spring. Stand frequency in the first year of establishment appeared to be highly dependent on seeding date and corresponding weed pressure. Late spring resulted in the highest stands and the early seeding date had the lowest mean stand frequency at 40.3%. The fall and mid-spring planted stands however were not statistically different. Early observances suggest that seeding methodology is not a significant determinant in stand frequency, however there was a significant interaction between seeding methodology and planting date. The dual roller seeder provided the highest stand frequency rating in the late spring, the conventional drill treatment was similar in the mid and late spring planting dates and the no-till treatment had a similar stand frequency across all planting dates. Second year yields and an additional site with a more rigorous chemical weed-control program will be used to further explore these results.