Controlling weeds without herbicides
Weeds are a serious biotic production constraint in most agricultural production systems. Acting at the same trophic level as the crop, weeds capture resources that cannot anymore be used by the crop. Therefore, leaving weeds uncontrolled will sooner or later lead to considerable reductions in crop yield.
Curative weed control is mainly focussed on weed seedlings and is strongly dominated by the use of herbicides. This heavy reliance on chemical control is considered objectionable because of potential negative side-effects on food safety, public health and the environment. Additionally, cropping systems with a narrow focus on herbicidal control are less sustainable, due to an increased risk regarding the development of herbicide resistance.
Cultural control refers to any adjustment of the general management of the crop that contributes to the regulation of weed populations and reduces the negative impact of weeds on crop production. This preventative approach addresses a variety of life cycle stages and relevant processes, like the weed soil seed bank, seed recruitment, weed seed production and seed predation. Various measures like photo-control, bio-fumigation, mulching, stale seedbeds, transplanting, weed suppressive cultivars and no till systems potentially contribute to this kind of ecological weed management.
The questions that remain are manifold, just to mention a few:
- Which life cycle stage of the weeds can best be tackled?
- How effective and reliable are individual cultural control measures?
- Do the measures combined provide synergistic effects?
- Are weed community changes likely to result from a modified management strategy?
- What is the role of crop rotation in ecological weed management?
Types of research
- Literature review with follow up analyses of already published data
- Experimental approaches to evaluate individual measures
- Population dynamical models to evaluate control measures and to study changes in weed community composition