ALFALFA ESTABLISHMENT WITH DIVERSE ANNUAL RYEGRASS CULTIVARS

There is limited information on forage yield and nutritional value of binary mixtures of annual ryegrass (Lolium multiflorum Lam.) with fora ge legumes in the north-central USA. A diverse set of annual ryegrass cultivars in binary mixtures with alfalfa (Medicago sativa L.) was eva luated for seeding-year forage yield and nutritional value and for for age yield and alfalfa presence the year after seeding. Annual ryegrass cultivars differing in ploidy and maturity were sown at 215 seeds m(- 2) with alfalfa at two locations in Wisconsin in spring 1990 and 1991. As a control, alfalfa was also sown alone. Seeding-year forage yields of ryegrass-alfalfa mixtures ranged from 5.00 to 10.65 Mg ha(-1) in 1 990 and from 7.06 to 8.96 Mg ha(-1) in 1991. Mixtures of alfalfa with early-maturing ryegrass cultivars were higher in yield and fiber fract ions (neutral- and acid-detergent fiber) and lower in crude protein co ncentration than mixtures with late-maturing ryegrass cultivars, with greater differences observed in 1990 than 1991. The ryegrass-alfalfa m ixtures usually were higher yielding but lower in forage nutritional v alue than alfalfa sown alone, with greater differences observed in 199 0 than 1991. Alfalfa stands were reduced by ryegrass in oen site-year, where conditions favored vigorous ryegrass development over alfalfa s eedling development. In the other three environment, alfalfa was succe ssfully established with all ryegrass cultivars, but alfalfa yields th e year after seeding were highest in plots established with early-matu ring diploid cultivars. The most suitable annual ryegrass companions f or alfalfa establishment in the north-central region are early-maturin g diploid cultivars.