||The lack of consistent summer pasture supply is a major limitation to livestock production in the mid-Atlantic region. Perennial warm-season grasses might provide a solution if managed for high quality. Experiments were conducted on separate well established
stands of Caucasian bluestem and ’Cave-in-Rock’ switchgrass at the Kentland Farm near Blacksburg, VA. Stages of grass maturity at harvest simulating pasture and hay systems were tested. Six interseeded legume species and two grass monoculture
checks, one with 56 kg N/ha applied in spring and after each harvest, the other with no N, were imposed as sub-plots. Legume species included alfalfa, red clover, sericea lespedeza, annual lespedeza, Illinois bundleflower, and purple prairieclover. Inter-seeded
legumes provided small yet improved yield and forage quality of perennial warm-season grasses in the legume-establishment year. In the year following establishment, grass mixtures with alfalfa, red clover, and, for switchgrass, sericea lespedeza yielded as much forage as N-fertilized grasses. Alfalfa and red clover altered the distribution of yield of the grasses, and may not be as compatible with perennial warm-season grasses as sericea lespedeza in the long-term. Interseeded legumes improved yield and quality significantly in terms of increased crude protein and lowered fiber concentrations in both, Caucasian bluestem and switchgrass in the second year.