OCL 2020, 27, 68 © R. Charles et al., Hosted by EDP Sciences, 2020 https://doi.org/10.1051/ocl/2020055 OCL Oilseeds & fats Crops and Lipids Available online at: www.ocl-journal.org REVIEW Organic rapeseed in Switzerland: 20 years of practice☆ Raphaël Charles1,*, Alice Baux2, Hansueli Dierauer3 and Claudia Daniel3 1 Institut de recherche de l’agriculture biologique (FiBL), Lausanne, Switzerland 2 Agroscope, Nyon, Switzerland 3 Forschungsinstitut für Biologischen Landbau (FiBL), Frick, Switzerland Received 22 April 2020 – Accepted 6 October 2020 Abstract – Rapeseed is a major oilseed crop in Europe, whose development has been a roller coaster ride over the last 20 years. In a context of increasing demand for organic products, this crop must however face numerous constraints concerning its demanding place in the rotation, a choice of varieties limited to line varieties at least in the Switzerland, a crucial implantation which must cope with variable water stress during sowing and winters with less and less frost, very demanding nitrogen nutrition requirements in the context of organic farming, and particularly harmful pests. A consolidation of the research devoted to rapeseed cultivation, but also a redesign of its cropping system and economic considerations should make it possible to better position this crop in relation to agri-environmental contexts, but also in relation to the complementary aptitudes of other oilseed crops. Keywords: rapeseed / oilseed crops / organic production Résumé – Le colza bio en Suisse : 20 ans de pratiques. Le colza est une culture oléagineuse majeure en Europe, dont le développement s’est fait en dents de scie ces 20 dernières années. Dans un contexte de demande croissante en produits bio, cette culture doit toutefois faire face à de nombreuses contraintes qui concernent sa placeexigeantedanslarotation,àunchoixvariétallimitéauxvariétéslignéesdumoinsdanslecontextesuisse,à une implantation cruciale qui doit composer avec des stress hydriques variables lors du semis et des hivers de moins en moins gélifs, à des besoins en nutrition azotée très exigeants dans le contexte de l’agriculture biologique, à des ravageurs particulièrement nuisibles. Une consolidation de la recherche consacrée à la culture du colza, mais également un re-design de son système de culture et des considérations économiques doivent permettre de mieux placer cette culture en fonction des contextes agri-environnementaux, mais également par rapport aux aptitudes complémentaires des autres cultures oléagineuses. Mots clés : colza / cultures oléagineuses / production biologique 1 Introduction local production is subject to economic competition from imported products. Swiss organic rapeseed now covers a high- The demand for organic rapeseed for use as edible oil is value niche market that is not easily accessible to consumers high. However, this crop is demanding. Several pests cause who prefer cheap imported oils or other varieties of oil. This large variations in yield. The crop requires a lot of nitrogen for weak situation on the domestic market means that other crops growth and therefore good soil quality for plant nutrition. The that are likely to diversify and complete the coverage of needs development of organic rapeseed followed the dynamics of for oilseeds need to be put into perspective, even though it is a organic farming in Switzerland. It was first developed for question of analysing them from both an economic and an specific organic markets, in particular since 1998 on the agronomic point of view. initiative of a pioneering organic cooperative (Biofarm). It was Beyond the limits linked to the economic context, rapeseed then supported by the retail sector, which undertook to expand remains a crop with a development potential that needs to be fi the range of organic products by offering organic rapeseed oil better de ned, with an important position in conventional as of 2006. Ten years later, like many other production sectors, agriculture, but facing high technical challenges when it comes to conducting it in organic farming. ☆ Contribution to the Topical Issue “Organic foods in the oil & protein crop supply chain / Le « Bio » dans la filière oléoprotéagineuse” * Correspondance: raphael.charles@fibl.org This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. R. Charles et al.: OCL 2020, 27, 68 While most field crops in organic agriculture mainly face For rapeseed, this means that hybrid varieties are prohibited as disease, weed and nitrogen nutrition problems, oilseed rape, long as lines are available, except for high oleic low linolenic like potato, faces pressure from specific pests: pollen beetle rapeseed, which is available exclusively as a hybrid variety. (Meligethes aeneus), stem weevils (Ceutorhynchus ssp.), flea Since 2014, in Switzerland, only restored hybrid varieties are beetles (Psylliodes chrysocephalus)(Niggli et al., 2016). The included in the list of conventionally recommended varieties. analysis proposed here focuses on the successes and failures of Therefore, an evaluation of line varieties available in Europe this crop in the context of Swiss organic farming over the last was conducted under organic conditions. Varieties adapted to 20 years. It examines its place in arable crop rotations, the key organic conditions were identified with high grain yield and factors governing the success of its cultivation, research needs good phoma tolerance (Luginbühl et al., 2017). Currently, and development prospects. two varieties are available and multiplied in Switzerland, Vision (2006) and Sammy (2012) (Dierauer and Klaiss, 2020). 2 Method Sammy stands out in particular for its early flowering, which is appreciated when the pollen beetle pressure is high. Several technical documents are made available for use in Part of the rapeseed production in Switzerland has also practice. Their content evolves according to feedback from shifted to varieties richer in oleic acid (and lower in linolenic practice and new knowledge. Their analysis allows to follow acid), which is more stable to heating than linoleic varieties. the evolution of practices in organic agriculture. Their cross- This production is under contract and organic production can referencing with literature from conventional agriculture helps also access it. Two varieties are currently available for to situate the specific issues of organic farming. An analogous conventional and organic production, V316OL and V350OL, fi fi restored hybrid varieties authorised in organic production for cross-reference with current scienti c literature clari es the fi evolution of the issues as well as persistent or new research this speci c production (Laurent et al., 2020). needs. A large part of the technical literature consulted comes 5 Sowing from the website bioactualites.ch (cited in the text as references from practice), as well as from the fact sheets The sowing date mainly determines the state of develop- made available to farmers and advisors involved in organic or ment of the rapeseed at the beginning of winter and has to deal conventional farming (explicitly referenced). with two contradictory objectives depending on the availabili- ty of nitrogen: a limited growth to ensure physiological 3 Position in the organic rotation resistance to frost and physical resistance to snow, but a high biomass (number of leaves, size of the crown) favourable for Rapeseed is a demanding crop for its nutrition and is the vegetation restart in spring. Despite the risks mentioned exposed to several pests during a relatively long growing and thanks to breeding efforts to limit elongation before winter, period. The crop thrives especially on soils with high natural the evolution of practices has shown a strong interest in early fertility. On farms with low or no livestock, its position in the sowing in organic agriculture (as in conservation agriculture). crop rotation should be considered. As a rule, rapeseed should Indeed, plant nutrition is highly dependent on the mineraliza- be placed at the beginning of the rotation in order to benefit tion dynamics of soil organic matter and organic fertilizers. from the regenerating effects of the grassland (compulsory in It generally does not benefit from substantial nitrogen residues Switzerland at 20% of crop rotation). This favourable from the previous crop like in conventional agriculture. positioning in relation to the evolution and cycle of organic Generally, an early sowing on a soil prepared accordingly matter in the rotation is all the more important for farms accelerates favourably the speed of emergence of rapeseed, without livestock (Fließbach et al., 2007). In terms of reduces its exposure time to seedling pests (slugs, flea beetles phytosanitary risk, rapeseed is seen more as a crop lightening Psylliodes chrysocephala) when rapeseed is the most the rotation compared to a significant presence of cereals. Crop vulnerable. Indeed, after stage B4 (4 leaves), the risk is rotation and landscape context are also interesting factors to reduced even if rapeseed is exposed. For flea beetles and stem take into account insofar as rapeseed flowering plays a major weevil, it is essential to have a strong biomass and, above all, a role in terms of biodiversity in arable crop regions, but also in continuous growth from sowing to the end of winter. Indeed,