Companion Crops for Legume Establishment: Forage Yield, Quality, and Establishment Success

Abstract

Alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), and birdsfoot trefoil (Lotus corniculatus L.) are the predominant forage legumes grown in the north central USA. Frequently these legumes are established with a companion crop to increase establishment year forage yield, reduce erosion, and suppress weeds. Information comparing forage yield, quality, and legume establishment using traditional companion crops of oat (Avena sativa L.) and oat+field pea (Pisum spp.) S. s. annual ryegrass (Lolium spp.) and festulolium (Festulolium braunii K.A.) companion crops is limited. This study was conducted to evaluate establishment year forage yield, quality and legume establishment success using five establishment methods. Four companion crops (oat, oat + field pea, annual ryegrass, festulolium) were sown with either alfalfa, red clover, or birdsfoot trefoil at two Wisconsin locations in 1993 and 1994. Each legume species was also established alone. Plots were harvested initially based on companion crop maturity and additional summer harvests were made when legumes reached midlate bud stage ofgrowth. Establishment year forage yields were higher when a companion crop was used than when the legume was solo seeded. At Ashland, WI, oat + field pea companion crop-legume mixtures were highest yielding in both years, averaging 0.60 ton dry matter (DM)/acre more than solo seeded legumes in the establishment year. At Marshfield in 1993 annual ryegrass and festulolium companion crop-legume mixtures yielded 0.65 ton DM/acre more than oat or oat + field pea companion crop-legume mixtures and 1.05 ton DM/acre more than solo seeded legumes. All companion crop-legume mixtures were equal, but higher yielding than solo seeded legumes in 1994 at Marshfield. Birdsfoot trefoil plots were consistently lowest yielding at both locations, except Marshfield in 1994 when alfalfa growth was suppressed due to excess moisture. Forage quality was directly related to the legume content of the harvested forage. Among the companion crops, annual ryegrass and festulolium were most frequently the highest in CP and lowest in acid detergent fiber (ADF) and neutral detergent fiber (NDF). Using annual ryegrass or festulolium as a companion crop for legume establishment may enhance the overal quality of forage harvested in the seeding year as compared with oat companion crops, and will increase yield over solo seeded legumes. In years that favor aggressive ryegrass growth, legumes may establish more slowly and may not produce as much forage in the year after establishment.