The competitive interactions between winter barley andAvena sterilisare site‐specific

Summary Competition between winter barley andAvena sterilisis expected to depend on the specific conditions present in a given site. Considering that site conditions may be variable within a field, we hypothesised that the lower densities ofA. sterilisfrequently observed under more favourable soil conditions can be attributed to the improved growth and competitiveness of the barley crop under those conditions. Artificial populations ofA. steriliswere established at three sites with different soil properties, both in the absence and the presence of a barley crop. Plant density, total biomass, dry weight per plant, seed production and seed per plant production were measured at different times in two growing seasons.Avena sterilisproved to be a generalist species when growing in monoculture, with similar seed production, regardless of the site conditions. However, when growing with the crop, differences in growth and seed production were observed at the different sites under some climatic conditions. The effect of the crop onA. sterilisbiomass and seed production was more pronounced at the sites with finer textures and higher organic matter and nitrogen contents, suggesting that barley site‐specific competitive ability may contribute to limiting weed populations in favourable soils.