|PAN, WILLIAM - Washington State University|
|MAAZ, TAI - Washington State University|
Submitted to: Crop and Pasture Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/5/2016
Publication Date: 5/6/2016
Publication URL: http://handle.nal.usda.gov/10113/62553
Citation: Pan, W.L., Young, F.L., Maaz, T., Huggins, D.R. 2016. Canola integration into semi-arid wheat cropping systems of the inland Pacific Northwestern USA. Crop and Pasture Science. 67:253–265.
Interpretive Summary: Rainfall divides the inland Pacific Northwest (PNW) wheat producing region from wheat-fallow to annual cropping systems. Since the 1970’s research and interest has suggested that oilseeds can be integrated into this region. However small-seeded oilseeds have not been adapted in the PNW compared to other semi-arid regions of the world because of unique agronomic, economic, and marketing constraints. Research has been undertaken and knowledge gained that has increased oilseed production in the region including: 1) seeding rate, date, and methodology studies to determine optimum time of planting canola; 2) nitrogen cycling, root system morphology, and fertility timing and rates to improve yield and winter survival; 3) short, medium, and long-term economic analyses to evaluate rotational benefits of inserting an oilseed into the wheat production system; and 4) socioeconomic impact of local market and distribution centers. Oilseed integration into the current wheat production system in the PNW can improve chemical, biological, and physical soil properties; mitigate weed resistance; improve yield and quality of subsequent crops; increase farm sustainability; and diversify production systems and markets for farmers.
Technical Abstract: The inland Pacific Northwestern USA (iPNW) wheat-producing region has a diversity of environments and soils, yet it lacks crop diversity and is one of the few semi-arid wheat-growing regions without significant integration of oilseeds. Four major agroecological zones, primarily characterised by water availability, feature distinctly different fallowed and annually cropped systems, each presenting different challenges and opportunities to integrate winter and spring canola. Although major interests in regional energy crops and rotational diversification spurred feasibility research on iPNW canola food, feed and fuel production in the 1970s, commercial canola adaptation has lagged behind other semi-arid wheat regions for various socioeconomic, ecophysiological and agronomic reasons. New federal crop insurance policies will reduce economic risks in new crop adaptation, and oilseed processing facilities are creating new local markets. Although canola management largely relies on wheat farm equipment, agronomic approaches require strategic adjustments to account for physiological differences between canola and cereals including seed size, seedling morphology and responses to temperature extremes. Climate change predictions for the region threaten to exacerbate current hot and dry summers and research aims to develop and adapt flexible winter and spring canola-based systems to regional water and temperature stressors in each zone. Adaptation will require novel planting, fertilisation and weed control strategies to successfully establish improved winter canola cultivars in hot dry summers that survive cold winters, and spring canola cultivars directseeded in cool wet springs. The adaptation of winter and spring canola will somewhat mirror the rotational placement of winter and spring cereals within each zone. Economic analysis of oilseed break crop benefits such as weed and disease control will help to demonstrate the medium-term economic benefits of crop diversification to support the growth of a regional canola industry in the iPNW.