Spatial and temporal patterns of Lolium rigidum-Avena sterilis mixed populations in a cereal field

Through a detailed case study of a two-species (Lolium rigidum and Avena sterilis) weed community at contrasting scales, this paper examined factors that affect weed distribution across space and time in a commercial wheat field in north-east Spain. A. sterilis showed relatively stable spatial distribution and spatial structure of its population over time at large scale, with well-defined patches, although weed density rose quickly. L. rigidum showed poorly defined patches that were not stable across time. Interaction between species could explain to some degree the spatial distribution at large scale: a negative relationship was detected between the spatial structures of both weed populations. At fine scale, both species showed a clear interaction effect from primary dispersal (more important in A. sterilis) and secondary dispersal from combine harvesting (more important in L. rigidum).