Submitted to: Crop Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2013
Publication Date: 5/7/2014
Citation: Young, F.L., Whaley, D.K., Pan, W.L., Roe, D., Alldredge, J.R. 2014. Introducing winter canola to the winter wheat-fallow region of the Pacific Northwest. Crop Management. DOI: 10.2134/CM-2013-0023-RS. Interpretive Summary: The winter wheat, highly erosive, weed infested tillage-fallow crop production system has been practiced on 60% of the wheat growing region of the Pacific Northwest (PNW) for over a century. Winter canola has the potential to be integrated into this low-rainfall cropping system, however producers are reluctant to grow winter canola because of lack of agronomic research for this crop and poor stand establishment when one or two producers have tried to grow it. From 2007 until 2011 experiments were conducted in north central WA in 10-inch rainfall zones to determine the optimum time and rate of winter canola planting. Using a modified deep-furrow, winter wheat drill, researchers found the optimum time of planting was from early to late August and air temperatures approximately 85 F for several days after planting. The cool temperatures are required to prevent the soil from getting too hot and killing the seedlings as they emerge through the soil. Optimum yields were not necessarily associated with high winter survival and high spring plant densities. Canola yields of 1500 lbs/acre to 1650 lbs/acre were realized with a 4 lb/acre seeding rate and an increased rate of 8 lb/acre did not increase yield because of intraspecific competition. Winter survival ranged from 56% to 83% with approximately 60% being average. The integration of winter canola into the winter wheat-fallow, low rainfall regions of the PNW would reduce weed and disease infestations of wheat, diversify growers production systems and markets, and improve soil quality.
Technical Abstract: Growers in the low-rainfall, winter wheat-fallow region of the Pacific Northwest are in need of an alternative crop to diversify their markets, manage pests, and increase wheat yields. Winter canola may be a viable crop option for growers in the region. However, agronomic research for winter canola in this region has not been conducted and growers are reluctant to produce winter canola because of poor stand establishment. This study evaluated various winter canola planting dates and rates on stand establishment and yield. Research with a modified deep-furrow drill indicated that winter canola needs to be planted in August with post plant temperatures of 85 F or less for successful stand establishment and acceptable yield of between 1500 lbs/acre and 1650 lbs/acre. September plantings (or very late August), unless covered by snow, either did not survive freezing temperatures or yielded <900 lbs/acre. Winter survival ranged from 56% to 83% with most survival approximately 60%. In general, the 4 lb/acre seeding rate was sufficient for stand establishment and yield. The higher seeding rates had too high of a population and intraspecific competition limited yield. A spring plant population between 2 plants/ft2 and 4 plants/ft2 will yield optimally. Integration of winter canola into the low-rainfall, wheat-fallow region of the Pacific Northwest will increase farm sustainability by improved pest management strategies and diversified production systems and markets.