Challenges and Benefits of Interseeding Legumes into Grass Dominated Stands

Interseeding legumes into grass-dominated stands can benefit pasture and hay producers by increasing the yield and quality of forage they produce and reducing their need for inputs of nitrogen fertilizer. The challenge is to get the legumes established given the competition from existing vegetation. This study confirmed that suppressing the grasses with glyphosate prior to seeding results in the most consistent legume establishment. Close mowing to simulate heavy grazing generally did not result in improved establishment. Of the 5 legumes evaluated, alfalfa established the best in the glyphosate treatment in Colorado, increasing yield by over a ton per acre. In Idaho, establishment was more variable with red clover establishing well regardless of suppression treatment. No legumes established at the Oregon site due to heavy rodent activity. This study highlighted the importance of suppressing the existing grasses and choosing a vigorous legume species for interseeding to reduce the risk of seeding failure.