Double-cropping oilseed sunflower after winter camelina

Double-cropping as a means of sustainably intensifying oilseed production could promote farmer adoption of new and alternative use oil crops like camelina [Camelina sativa (L.) Crantz]. Previous research indicated that double-cropping sunflower (Helianthus annuus L.) after winter camelina in the upper Midwest USA tended to reduce sunflower seed yield and oil content as compared with monocrop sunflower. However, new semidwarf hybrid sunflower genotypes with early maturity may be better suited for developing double-cropping systems for oil production in the upper Midwest and northern Great Plains. To evaluate seed and oil yields of winter camelina (cv. Joelle) and double-cropped sunflower compared with monocrop sunflower, a field study was conducted across two growing seasons (2017–2019) in west central Minnesota USA. One early maturing semidwarf oil sunflower hybrid, Honeycomb NS, and three common commercial full season oil hybrids were evaluated. Additionally, soil moisture to a 1-m depth was monitored during both growing seasons, which did not appear to limit production of the two crops in a single season at the study site. Although delayed sowing associated with double-cropping generally reduced sunflower seed yield, oil content, and the oleic/linoleic acid ratio compared with monocrop controls, these decreases were less for the early maturing hybrid Honeycomb NS. During one season of the study, total oil yield (winter camelina + sunflower) of double-cropped Honeycomb NS was 1.5 times greater than its monocrop counterpart. In addition to sustainably intensifying oil production, double-cropping sunflower with winter camelina might appeal to producers wanting to reduce the risk of one or the other crop failing in any given year. Nevertheless, double-cropping in the upper Midwest USA can be risky due to year-to-year variations in weather and length of growing season.