Information on weed spatial distribution could improve weed management decisions. Herbicide use could be reduced if applied only to field zones with an infestation level higher than a specific economic threshold. In this study, we surveyed 31 winter barley fields in different regions of Spain to describe the spatial distribution of sterile oat and to analyze the relationship between sterile oat infestation level and landscape and crop yield attributes. Elevation and slope angle, crop yield and slope aspect were the main factors in order of importance in explaining the distribution of sterile oat. In general, greater infestation levels were observed in flat lowland and concave landscapes, with a low crop yield, and on northern exposures (when slope ≥ 2%). We could define field zones with a higher risk (> 6 times probability) of having sterile oat problems. High-probability zones, defined by topographic attributes alone, occupied 24% of the total area and contained 46% of the high infestation levels, whereas zones defined by topographic and crop yield attributes constituted 14% of the total area and contained 31% of the infestation.

Nomenclature: Sterile oat, Avena sterilis L. AVEST; barley, Hordeum vulgare L.