Pre-Harvest Assessments of Elymus repens (L.) Gould Interference in Five Arable Crops

Abstract

Relationships between yield of five arable crops and increasing Elymus repens infestations assessed near before harvest are presented from field trials conducted on the same location through four years. In peas, spring barley and spring oilseed rape, yield responses to E. repens interference were closely related to E. repens shoot biomass pre-harvest. Also the number of E. repens spikes pre-harvest was related to crop yield, although the correlations were not as high. In winter wheat and winter rye, the correlations, with both shoot biomass and spike number, were smaller than in the spring-sown crops, but still significant. In all crops, the relationships interacted with years but the interactions were not statistically significant in many cases. Mechanical control in the stubble and pre- or post-harvest application of glyphosate are common control measures against E. repens, and pre-harvest assessments of E. repens infestations show promise for judging the seriousness of a current E. repens problem before making control decisions.

Key Words:

• competition
• oilseed rape
• peas
• shoot biomass
• spike number
• spring barley
• winter rye
• winter wheat
• yield loss