Wild oat and barley interactions: varietal differences in competitiveness in relation to phosphorus supply

Nine cultivars of barley (Hordeum vulgare L.) were separately planted with wild oat (Avena fatua L.) in sand culture at two external phosphorus concentrations. Barley cultivars differed substantially in their ability to compete with wild oat. Relative competitive abilities of the barley cultivars were strongly influenced by external phosphorus levels. The greatest effect of competition, particularly at low external phosphorus, was upon plant biomass rather than on internal total phosphorus concentration. The selection of cultivars that are able to compete effectively with wild oat may represent an alternative (biological) strategy to the traditional one of herbicide application.