Approaches for optimising linseed cultivation in Switzerland

Despite state financial support (oilseed payments) for linseed, linseed is still a fairly insignificant oilseed crop in Switzerland. Over the last few years, however, the area under organic cultivation of this crop has been significantly expanded. With the aim of improving yield stability, in small-plot trials, comparisons of autumn vs. spring sowing and of two different harvesting techniques – direct threshing and threshing after swathing – as well as comparisons of three seeding densities were conducted. The sowing of winter-hardy varieties in autumn achieved higher yields than did the spring sowing. The fatty-acid profile was influenced only slightly by the sowing date, and the studied varieties – Everest, Alaska, Banquise and Iceberg – exhibited linolenic-acid contents in oil of between 55 % and 61 %. With swathing, especially where weed infestation was high, it was possible to reduce the water content in the harvested crop. In three out of four experiments, no disadvantage in terms of yield was observed from swathing. The three varieties Altess, Niagara and Récital reacted similarly to the three different seeding densities, with the lowest seeding density (250 seeds/m2) leading simultaneously to a lower yield and a higher water content at harvest. Choosing the optimal seeding density, employing a harvest technique corresponding to field conditions, and – where possible in terms of crop rotation – cultivating winter-hardy linseed varieties can all make a substantial contribution to successful linseed cultivation.