WEED INVASION IN ESTABLISHED ALFALFA (MEDICAGO-SATIVA) SEEDED WITH PERENNIAL FORAGE GRASSES

Component yields and forage quality were evaluated in established stan ds of alfalfa seeded alone and in binary mixtures with smooth bromegra ss, orchardgrass, or timothy. Forage yields and quality were determine d at three annual harvests in the third and fourth years after seeding . Weed yields in alfalfa seeded alone were significantly greater than those in the alfalfa-orchardgrass mixture. Average weed content was 24 , 17, 2, and 15% for the alfalfa seeded alone, alfalfa-bromegrass, alf alfa-orchardgrass, and alfalfa-timothy, respectively. Seeding alfalfa with orchardgrass increased first harvest and annual forage yields whi le reducing alfalfa yield. Yields of orchardgrass often exceeded those of bromegrass or timothy. In the first harvest each year, crude prote in was reduced and acid detergent fiber and neutral detergent liber in creased by including orchardgrass. Neutral detergent. fiber was greate r in alfalfa-orchardgrass than in the alfalfa seeded alone at most har vests. There were no consistent differences among the alfalfa seeded a lone and the other mixtures in yield or quality.