Yield of Three Range Grasses Grown Alone and in Mixtures with Legumes

Four legumes and 3 grasses in combination, and the 3 grasses alone were evaluated for forage yield and persistence for 9 years in north-central Colorado. Sicklepod milkvetch (Astragalus falcatus), alfalfa (Medicago sativa), sainfoin (Onobrychis viciifolia) or crownvetch (Coronilla varia) were planted in alternate rows with crested wheatgrass (Agropyron desertorum), Russian wildrye (Elymus junceus), or pubescent wheatgrass (A. trichophorum). Crownvetch failed to become established. Sainfoin, a short-lived species under Colorado range conditions, was gone within 5 years. Alfalfa persisted 7 years; it was killed by a combination of drought and pocket gophers. Sicklepod milkvetch persisted for the entire period. This site was too dry for pubescent wheatgrass and its stand declined rapidly. Crested wheatgrass with sicklepod milkvetch or alfalfa, and Russian wildrye with alfalfa produced the highest total yields. All grass-legume mixtures involving crested wheatgrass and Russian wildrye produced significantly more forage than the grasses grown alone in 30 cm row spacing. Crude protein content was higher for grass-legume mixtures than for the grass alone.