Growth and yield of pure and mixed crops of oats and barley.
Mixtures of equal numbers of plants of different barley varieties or of a barley variety and an oat variety were grown in 5 field trials and 1 glasshouse trial. Grain yields of mixtures in the field were usually similar to the means of the yields of the components grown alone, while in the glasshouse they were usually similar to those of the greater yielding component grown alone. In the field, the use of mixture components differing in time-to-maturity had little effect on the yield of mixtures. Mixed crops of oats and barley were less responsive to N than barley, but were more responsive to irrigation than pure stands of either cereal. Barley was always dominant in field mixtures and yielded 18% more grain than when grown alone; the barley grew faster than when grown alone, the oats more slowly. The competitive advantage of barley in mixtures was due to its larger seed. In the field, pure stands of oats and barley had similar total DM yields but barley yielded more grain. In the glasshouse, the competitive roles of the 2 species were reversed after ear emergence, when oats became dominant and eventually produced more DM and grain than barley.-R.B.