Oilseed crops for semiarid cropping systems in the northern Great Plains

Oilseed crops are grown throughout the semiarid region of the northern Great Plains of North America for use as vegetable and industrial oils, spices, and birdfeed. In a region dominated by winter and spring wheat (Triticum aestivum L. emend. Thell.), the acceptance and production of another crop requires that it both has an agronomic benefit to the cropping system and improve the farmers' economic position. In this review, we compare the adaptation and rotational effects of oilseed crops in the northern Great Plains. Canola (Brassica sp.), mustard (B. juncea and Sinapis alba L.), and flax (Linum usitatissimum L.) are well adapted to cool, short-season conditions found on the Canadian prairies and northern Great Plains border states of the USA. Sunflower (Helianthus annuus L.) and safflower (Carthamus tinctorius L.) are better adapted to the longer growing season and warmer temperatures found in the northern and central Great Plains states. Examples are presented of how agronomic practices have been used to manipulate a crop's fit into a local environment, as demonstrated with the early spring and dormant seeding management of canola, and of the role of no-till seeding systems in allowing the establishment of small-seeded oilseed crops in semiarid regions. Continued evaluation of oilseed crops in rotation with cereals will further expand our understanding of how they can be used to strengthen the biological, economic, and environmental role of the region's cropping systems. Specific research needs for each oilseed crop have been recommended.