Agronomic and Economic Comparison of Potential Winter Oilseed Species and Varieties for Tennessee

Winter oilseed crops are annual cool season Brassica crops which fit well within typical corn and soybean rotations. They are currently being adopted in Midwestern conventional agriculture systems. The ability to produce sustainable aviation fuel (SAF) from oil pressed from the seeds is the driving force of recent interest in the crops. The three main crops of interest in this study are canola (Brassica napus), pennycress (Thlaspi arvense L.), and camelina (Camelina sativa). To determine if production of winter oilseeds is feasible in Tennessee, three experiments were conducted. First, a field study variety trial was evaluated for winter oilseed ground coverage, seed yield, oil content, and subsequent soybean yield and quality. After two years of study at two locations in Tennessee, canola and pennycress performed well, while camelina did not survive the winters. Second, a bioassay was conducted to determine possible allelopathic effects of water extractable chemicals from canola and pennycress roots and stubble on the subsequent crop and spring weeds. Seeds of soybean (Glycine max), mare’s tail (Erigeron canadensis), and palmer amaranth (Amaranthus palmeri) were treated with extracts and evaluated for germination percentage, radicle length, and hypocotyl length. Water extractable compounds from canola and pennycress inhibit growth and germination of the herbicide resistant weeds, while not affecting soybean. Lastly, an economic analysis of winter oilseed production was conducted. Based on practices and yields from the field study, budgets were created for canola and pennycress, and breakeven and profitability analyses conducted. At present yields, inputs, and projected prices, canola production in Tennessee for biofuel production is profitable while pennycress is not profitable. With further research, increased breeding efforts, and the creation of a market for biofuels from winter oilseeds in Tennessee, winter oilseeds may become a valuable double crop to Tennessee producers.