Ryegrass Companion Crops for Alfalfa Establishment: I. Forage Yield and Alfalfa Suppression
- R. M. Sulc,
- K. A. Albrecht and
- M. D. Casler
Alfalfa (Medicago saliva L.) is often established with a small grain companion crop in the northcentral USA. Information on alternative companion crop species is limited. This study was conducted to evaluate forage yield and alfalfa establishment when ryegrasses (Lolium spp.) are used as companion crops. Five ryegrass cultivars representing four species were sown at 215, 430, and 645 seeds m−2 with alfalfa at two locations in Wisconsin in April of 1988,1989, and 1990. Alfalfa was also established alone or with oat (Avena saliva L. ‘Ensiler’). Three harvest schedules, based on oat maturity at the first harvest, were imposed during the seeding year. The ryegrass-alfalfa mixtures usually had lower forage yields in the seeding year than the oat companion treatment. But mixtures with the diploid annual ryegrass (L. muliflorum Lam. ‘Surrey’) yielded up to 1.17 Mg ha−1 more than the oat companion treatment in environments with adequate rainfall. When rainfall was limiting during early establishment, alfalfa predominated in all ryegrass-alfalfa mixtures, and forage yield and alfalfa plant density the next year were excellent in the ryegrass companion treatments. Ryegrass was very competitive with alfalfa in seeding years with adequate rainfall, and forage yield and alfalfa plant density the next year varied considerably with ryegrass cultivar, ryegrass seeding rate, and harvest schedule. The diploid annual ryegrass (Surrey) sown at 215 seeds m−2 was the most suitable ryegrass companion crop for alfalfa establishment because it established rapidly, produced high forage yields in the establishment year, and had the least detrimental effect on forage yield and alfalfa plant density the year after seeding.
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