ABSTRACT
Selecting effective weed management options requires biological, ecological, and economic information. This study compared model-based to standard-herbicide weed control in a corn (Zea mays L.)/soybean [Glycine max (L.) Merr.] rotation that had a long-term history of different tillage and weed management practices. The model integrates weed population dynamics, herbicide efficacies, and economic information to evaluate preplant incorporated (PPI) or preemergence (PRE) weed control options based on weed seed bank size and postemergence (POST) strategies based on weed seedling densities. There were fewer weeds in standard-herbicide compared with model-based treatments. No-tillage had the greatest numbers of weeds 3 out of 4 years. Soybean yield was reduced the first year of the study in several treatments receiving model-based weed control and the third year in all model-based treatments. Com yields were greatest in reduced tillage. Results 208of using model recommendations to control weeds were mixed, with PRE recommendations being insensitive to a common cocklebur (Xanthium strumarium L.) infestation. Our conclusions agree with those of others that the nature of the weed pressure may be a prevailing influence on the outcome of using weed control recommendations of bioeconomic models. [Article copies available for a fee from The Haworth Document Delivery Service: 1-800-342-9678. E-mail address: getinfo@haworthpressinc.com]
