Intercropping Dual-Purpose Winter Canola with Wheat and Peas.

Monoculture and limited crop rotations throughout the United States are contributing to an increase in crop pests, disease, and weeds. Including dual-purpose biennial winter canola in rotations could allow greater profitability and sustainability in the Pacific Northwest by providing an economically viable alternative crop. In the first year, vegetative growth of winter canola provides high protein, low fiber livestock forage, with an oilseed crop in the second year. The oilseed can be pressed and used as a healthy cooking oil or a biofuel feedstock, with a high quality seed meal byproduct, which is suitable for livestock feed. By intercropping canola with a higher fiber spring forage (i.e. spring wheat) in the first year it may be possible to increase forage yield and increase fiber without negatively impacting seed yield. Alternatively, intercropping canola with a legume may help offset the cost of additional nitrogen resulting from forage harvest. This study compared dual-purpose biennial winter canola alone with canola-wheat and canola-pea intercrops at two locations, Moscow and Genesee, Idaho. Two imidazolinone resistant lines of canola planted at 4.5, 6.7 and 9.0 kg ha^-1 were mixed with imidazolinone resistant wheat at 22.4 and 44.8 kg ha^-1 or peas at 44.8 and 85.6 kg ha^-1. Plots were assessed for percentage dry matter, neutral detergent fiber, acid detergent fiber, crude protein, relative feed value, crude fat and ash. Forage yield was maximized with canola seeded at 9 kg ha^-1 and wheat at 22.4 kg ha^-1, producing 9.0 Mt ha^-1 dry matter, with a relative feed value of 278 and a crude protein of 18.7%.