Double-cropping with winter camelina in the northern Corn Belt to produce fuel and food

► Winter camelina was double-cropped with soybean, sunflower, and forage millet. ► Oil yield of double-crop oilseed sequences averaged 704 to 1508Lha−1. ► Double-crop soybean and sunflower yielded 82 and 72% of their mono-crop counterparts. ► A winter camelina-food/–forage crop double-crop system may be economically viable. Camelina (Camelina sativa L.) can be used as oilseed feedstock for biofuels. Recently, it was shown that fall-seeded winter camelina can be successfully grown in the upper Midwest USA and may be harvested early enough in the following summer to allow producing a second crop. Double-cropping may offer a profitable means of producing a dedicated biofuel crop without jeopardizing food security. To our knowledge no published information exists on exploring double-cropping with winter camelina. Therefore, a 2-yr field study was conducted between 2007 and 2009 in west central Minnesota to evaluate the agronomic and economic viability of producing short-season cultivars of soybean [Glycine max (L.) Merr.], oilseed sunflower (Helianthus annuus L.), and forage millet (Setaria italica L.) after winter camelina in conventionally tilled and no-tilled soil. In most instances, yields of camelina and the second crop in the double-crop sequence differed between years but not by tillage practice. Averaged over both years, total oil yields for the camelina–soybean and camelina–sunflower sequences were 704 and 1508Lha−1. Compared to conventionally produced mono-crops, on average, double-crop soybean and sunflower yielded 82% and 72% of their mono-cropped counterparts, respectively. As expected, double-crop production costs were greater than for conventional mono-crops. However, in 2009 if camelina prices were similar to canola, net returns for double-crop camelina and soybean were $172–352ha−1 higher than for soybean alone, with highest double-crop net returns for conventional tillage. Furthermore, double-crop soybean seed protein content was little affected by late seeding, while double-crop sunflower oil content averaged over both years was about 13% lower than conventional sunflower sown at an optimum time. A winter camelina-food or -forage crop double-cropping system may be viable for the upper Midwest USA.