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Carr, P.M., G.B. Martin, J.S. Caton, and W.W. Poland. 1998. Forage and nitrogen yield of barley-pea and oat-pea intercrops. Agron. J. 90:79-84. Barley (Hordeum vulgare L.) and oat (Avena sativa L.) have been intercropped with field pea [Pisum sativum subsp. sativum var. arvense (L.) Poir.] to increase forage yield and quality. Our objective was to evaluate the effects of two barley and two oat cultivars and seeding rates of cereal-pea intercrop on forage production, crude protein (CP) concentration, and N yield. A field experiment was conducted in 1993 and 1994 under dryland management in both fallowed and continuously cropped, no-tillage environments. 'Bowman' and 'Horsford' barley, and 'Dumont' and 'Magnum' oat, were each sown at 93, 185, and 278 kernels m-2 with 'Trapper' pea at 40, 80, and 120 seeds m-2, in all possible rate combinations. The cereal cultivars also were sown alone at 185 kernels m-2. Cultivars developed for forage production (Horsford, Magnum) produced as much or more forage than cultivars developed for grain production (Bowman, Dumont) across sole-crop and intercrop plots (P < .05). Forage yield was unaffected by intercropping when the cereal crop was sown at the sole-crop or greater rate. Less forage was produced by intercrops when the cereal component was sown at half the sole-crop rate. Forage yield was not affected by the pea seeding rate, but CP concentration increased with increasing seeding rate of pea in three of four environment-years. Forage N yield was unaffected by intercropping. These data indicate that the cereal component in barley-pea and oat-pea mixtures should be sown at a sole-crop or greater seeding rate for maximum forage production. Forage CP concentration can be increased as the relative proportion of pea seed to cereal kernels sown in a mixture is increased, but forage N yield may not be affected since the cereal component contributes more to yield than the pea component.