Development and application of a heuristic for flexible decisions about herbicide use in crop rotation field experiments

Abstract

Weeds in agriculture are controlled indirectly by strategic management tools (crop rotation, fertilization, tillage). Herbicide use is a direct tactical management tool for weed control. However, strategic and tactical measures interact together regarding weed management and thereby influence weed infestations and herbicide use. This study investigated the impact of strategic and tactical decisions in combination. It describes the development of a heuristic, which can be applied for different weed situations. By considering weed densities and species specific loss factors flexible herbicide decisions are derived for specific weed infestations and a given herbicide intensity. The implementation of decisions based on the heuristic is shown as an example for winter wheat crops in a rotation experiment at the study sites Rostock and Göttingen (Germany). The intensity of herbicide use serves for contrasts with three degrees (high, medium and low) representing three levels of target efficacy (100%, 85% and 60%). The introduced heuristic enables reproducible decisions for various weed infestations. First results show reduced herbicide use from high to the low level of herbicide intensity in terms of reduced numbers of active ingredients use.

Keywords

• herbicide use
• strategic and tactical decisions
• weed infestation
• winter wheat