Nitrogen fertilisation of linseed influences seed yield and oil quality

Despite the oilseed production payment, linseed has remained a relatively unimportant oil plant in Switzerland. Nitrogen (N) fertilisation is a core component of linseed cultivation, since linseed is considered to be a fairly undemanding crop, yet one that is susceptible to lodging when over-fertilised with N. With the aim of studying the reaction of recently released varieties to different nitrogen levels, small-plot trials were conducted with the three summer linseed varieties Baladin, Princess and Récital. Above all, the results illustrate the importance of site factors for the variability of seed yield. Despite this, and based on the current organic-producer price as well as the Biorga fertiliser price, an economically efficient fertilisation optimum of 36 kg N/ha can be deduced. Since a negative correlation was also observed between N-fertilisation intensity and α-linolenic acid content, moderate N-fertilisation is likewise recommended for the production of high-quality linseed oil. However, significant differences between the fatty-acid profiles of the three linseed varieties studied show that the choice of variety is also an important element in the production of a high-quality oil.