Mitigation of seed germination impediments in hairy vetch

Hairy vetch (Vicia villosa Roth) is a promising winter cover crop for northern climates, but germination can be limited by low soil moisture conditions. Farmers may be reluctant to use hairy vetch, concerned that hard seed will emerge as weeds in succeeding crops. This work examines germination, dormancy, and viability of hairy vetch seeds from nine commercial seed sources, and evaluates the effects of mechanical scarification and ambient temperature hydropriming on the degree of hard-seededness, germination, seed viability and seedling vigor in a range of simulated soil moisture conditions. Hydropriming increased germination by 5% across seed sources and water potentials, but reduced seedling growth by 16%. Mechanical scarification eliminated all hard-seededness, but increased physiologically dormant seed by ~5% and nonviable seed by ~2% and reduced seedling growth by 39%. This work indicates that pretreatments may increase germination and reduce hard-seededness, but reduce seed viability and seedling vigor in some seed sources.