Assessment of a decision support system for chemical control of annual ryegrass (Lolium rigidum) in winter cereals

Field studies were conducted at five locations in North and East Spain to evaluate the agronomic, economic and environmental implications of a decision support system (LOLIUM-PC) for herbicide control of Lolium rigidum in winter cereals. The chemical control treatments evaluated were as follows (i) LOLIUM-PC-based recommendations, (ii) full herbicide dose (standard farmer practice) and (iii) half herbicide dose. Results indicate that there were no statistically significant differences, within sites, between treatments with respect to weed density, crop yield and economic return. On average, LOLIUM-PC resulted in less herbicide application compared with the full herbicide dose treatment. This also was true in three of five localities for the half-dose treatment. The results of this research indicate that LOLIUM-PC provides a flexible tool for recommending less herbicide than other herbicide decision systems, adequate weed control and similar crop yields to those obtained with the standard farmer practice (full dose) in Spain. © 2011 The Authors. Weed Research © 2011 European Weed Research Society.