First steps toward developing Lewis flax (Linum lewisii Pursh.) as an agronomic crop

Authors: PULL, ZACHARY - North Dakota State University; GRAMIG, GRETA - North Dakota State University; Hulke, Brent; GOSSWEILER, ANDRE - North Dakota State University; JOHNSON, BURTON - North Dakota State University

Submitted to: Renewable Agriculture and Food Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/7/2023
Publication Date: 8/14/2023
Citation: Pull, Z., Gramig, G., Hulke, B.S., Gossweiler, A., Johnson, B. 2023. First steps toward developing Lewis flax (Linum lewisii Pursh.) as an agronomic crop. Renewable Agriculture and Food Systems. 38:1-8. https://doi.org/10.1017/S1742170523000340.
DOI: https://doi.org/10.1017/S1742170523000340

Interpretive Summary: Lewis flax is a close relative of cultivated flax that is native to the western USA and is adapted to marginal lands. The purpose of this work was to determine if and how this plant, with these adaptations, could be used as an oilseed crop that is rich in omega-3 fatty acids. An adaptive management approach was used to develop basic agronomic recommendations for establishment and weed control. Planting was optimal as an autumn seeded, late autumn dormant seeded, or early spring seeded crop, with avoidance of heavy rain and severe weather events being the most important consideration. No yield differences were observed between planted populations or row arrangements, so a low seed rate combined with seeding on 30 inch row spacing resulted in the most management-friendly outcomes. This row spacing allowed for inter-row cultivation with tractor mounted equipment. Weed control methods, such as flame-weeding, were attempted, but resulted in too much off-target damage to the Lewis flax to be practical. We also attempted companion cropping Lewis flax with winter wheat, which successfully reduced weed pressure during establishment, but more work is needed to optimize companion crop recommendations.

Technical Abstract: Perennial Lewis flax (Linum lewisii Pursh) has the potential to be a new crop that could simultaneously meet commodity production, ecosystem service provisioning, and farm resiliency goals. Despite many potential benefits, Lewis flax remains minimally explored as an agronomic crop. Determining agronomic best practices for producing economically relevant stands of Lewis flax is critical to its adoption as an oilseed crop. Several aspects of Lewis flax production were assessed through the lens of adaptive management between 2020 and 2022. Initial field trials aimed at assessing spring-seeded Lewis flax row spacing and intercropping with legumes and grasses failed due to poor establishment. Heavy rains and excessive weed pressure further complicated attempts to reestablish these initial trials. We established additional Lewis flax plots via fall and dormant seeding in response to the failure of our first experiment. This second experiment focused on row spacing, population density, and seeding timing. Flax yield did not differ among our treatments, averaging 59 kg ha-1. The low yields realized by our field trials may be due to several factors including need for harvest technology optimization, high weed pressure, and lack of Lewis flax genetic development. Our study is a first step toward developing recommendations for optimal production strategies for Lewis flax in an agronomic context. Continued exploration of methods to improve management and yield of Lewis flax will be critical to its successful development as an agronomic crop.