Overseeding Legumes in Cool-Season Pastures
Overseeding legumes into cool-season pastures is a method of improving forage quality and productivity during July and August when grass growth slows down. Brome, orchardgrass, tall fescue and Kentucky bluegrass are grasses from this region that are compatible with legumes in pastures. Legumes are valuable in pastures because they increase the protein content of the forage. Legumes also fix nitrogen from the air, which adds nitrogen to the soil. Grass-legume pastures that contain 30 percent legumes may not benefit from additional nitrogen fertilizer. It is cheaper to establish a grass-legume pasture than top dress your grass with nitrogen. With tall fescue, the addition of legumes in pastures will help dilute down the effect the endophyte has on livestock.
Legumes that have been successfully overseeded into cool-season grasses in the area include red clover, annual lespedeza, and ladino clover. These three appear to be the easiest to establish and maintain stands with periodic reseeding every 2-3 years. The first step in overseeding legumes is to test the soil and determine what nutrients are needed for establishment. Phosphorus is critical at the time of establishment and better stands are obtained if phosphorus is applied just before or at the time of seeding. Nitrogen should not be used at seeding as it increases the growth of the grasses and increases competition for the new legume seedling.
Prior to overseeding legumes, the pasture should be overgrazed during fall and winter. Fertilizer and lime can be applied during this time as well. Legumes should be broadcast in winter so freezing and thawing will cover the seed. Late February is usually the best time to seed in this area. Of the three legumes mentioned, ladino clover is the easiest and cheapest to establish, red clover is the most productive, and annual lespedeza is the most versatile. For more information on overseeding legumes into cool-season grasses and to determine what legume is best for your pasture situation, contact your local Extension Office.