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.
Stucky T., Hochstrasser M., Meyer S., Segessemann T., Ruthes A. C., Ahrens C. H., Dahlin P., Pelludat C.
The root knot nematode (RKN) Meloidogyne incognita causes damage in field and greenhouse crops. Agroscope researchers have developed a new screening test to identify bacteria that antagonise this agricultural pest.
With CULTAN fertilisation, nitrogen is injected into the soil as an ammonium solution. Multi-year trials conducted by Agroscope show that this method reduces nitrogen leaching by an average 38% without negatively affecting yields.
Tuta absoluta is one of the most destructive pests of solanaceous crops. Agroscope has developed a statistical model to study the population dynamics of the pest and its parasitoids and allows interventions to be optimally planned.