Cover crops represent an increasingly widespread agricultural technique in Switzerland as they provide different ecosystem services. One important role of cover crops is weed control, which can be explained by resource competition (for water, nutrients and light) and allelopathic effects (biochemical interactions between plants). To better understand the phenomenon of weed suppression by cover crops, we set up a field experiment that has allowed us to measure the effect of three cover crops on weed growth, particularly amaranth. In addition, we tried to understand the role of different weed growth suppression factors by using a new experimental approach. It allowed us to study separately the factor of light competition by the plant cover and the allelopathic root interactions between the cover crops and the amaranth plants. In this first year of the trial, light competition could be strongly reduced, but root interactions in the field could not be prevented completely due to methodological reasons. The intermediate results have demonstrated clearly the important role of light competition for weed control in the field. The role of allelopathy in weed suppression by cover crops remains to be identified.
Herbicide-resistant weeds are a growing problem throughout the world. Monitoring herbicide resistance in Switzerland allows us to understand the mechanisms behind it and to better manage the use of herbicides.
Agroscope compared crop protection strategies in apple production. Reducing the use of plant-protection products lowered the local ecotoxological risks, but resulted in trade-offs between environmental and economic performance.
Bacillus thuringiensis (Bt) bacterium proteins protect Bt maize from being fed on by specific insects. A new, systematic analysis of international field data confirms that non-target organisms in Bt maize are largely spared.