The growth of companion cropping in oilseed rape: feedback on the opinions of Swiss producers

The practice of sowing companion crops (or «service plants») in among oilseed rape began to get off the ground in Switzerland several years ago. Certain farmers see companion cropping as an innovative technique allowing them to cut back on the use of plant-protection products, and in particular enabling them to forgo the use of herbicides, an approach which is federally subsidised. For others, this technique is in need of fine-tuning, and poses too great a risk to yields. A survey distributed among Swiss oilseed rape producers in spring 2018 collected their practices and opinions regarding companion cropping in oilseed rape. The survey reveals significant disparities between French-speaking Switzerland, where this technique is already well known, and German-speaking Switzerland, where it is just getting off the ground. The majority of producers acknowledge the possibility of giving up herbicide use thanks to companion cropping in oilseed rape, but many still fear a drop in yield. The choice of species sown with the oilseed rape depending on the services expected is an important element revealing different strategies among the producers.