Barley, oat, and cereal-pea mixtures as dryland forages in the Northern Great Plains

Oat (Avena spp.) is a popular cereal forage in cool semiarid regions. Barley (Hordeum vulgare L.) has produced equal or greater amounts of superior quality forage in subhumid regions. The importance of cereal crop, cultivar, and plant part on forage production was determined in low-soil-N environments in southwestern North Dakota. Barley and oat cultivars, along with intercrops of pea (Pisum sativum L. subsp. sativum) with barley and oat, were compared for forage yield and quality over 2 yr. Forage dry matter (DM) yield averaged 3.84 Mg ha(-1) for oat compared with 2.91 Mg ha(-1) for barley while crude protein (CP) concentration of oat forage averaged 61 g kg(-1) compared with 90 g kg(-1) for barley (P < 0.05). No difference in forage N yield occurred between barley and oat. Acid detergent fiber and neutral detergent fiber concentrations averaged 39 and 41 g kg(-1) lower, respectively, for barley compared with oat forage while Ca and P concentrations were higher for barley forage. Cultivar selection within each crop species generally did not affect forage yield or quality. The relative contributions of stem, inflorescence, leaf blade, and leaf sheath to forage yield were similar between cereal species and averaged 20, 44, 14, and 22%, respectively. Intercropping with pea increased forage and N yield. These results suggest that forage yield is reduced but quality is enhanced when oat is replaced with barley in low-soil-N, unfertilized environments. Furthermore, the results indicate that forage yield and quality can be enhanced by intercropping barley or oat with pea.