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Novel cultural and mechanical weed control for flax

Activity summary

Production of both conventional and organic flax is difficult because, of all major field crops grown in western Canada, flax is the least competitive with weeds. This lack of weed competition makes growing organic flax particularly difficult, as weeds can often reduce its yield to almost zero. One innovative solution that has been used by farmers is intercropping flax with fall rye. In this system, fall rye is seeded and then flax is cross-seeded in the field. Both crops emerge and the flax grows erect and above the rye. As the fall rye has not vernalized, it grows vegetatively and remains prostrate to the ground where it acts as a cover crop. To ensure the rye does not vernalize, seeding takes place in late May to avoid cold weather. Following this, the rye is simply left in the field to overwinter. The next year the rye can be harvested, as it will have vernalized over winter and will now become reproductive.

Another alternative method to control weeds in flax may be through mechanical weed control. Mechanical weed control is common in many crops, but initially it was assumed to not be possible in flax because of the small seed size and relatively weak seedling. Although these seedling characteristics make in-crop harrowing impossible, we have recently determined that flax appears be tolerant to rotary hoeing at most crop stages. Steerable inter-row cultivators are able to cultivate between crop rows and control larger weeds.

The overall objective of this research is to develop novel weed control methods for organic flax production. To test this overall objective the following sub-objectives will be assessed using field experiments:

1. Determine the effect of fall rye cover crop and mechanical weed control on weed control and yield in organic flax.
2. Determine the effect of winter cereal presence and species on flax yield and subsequent (year 2) crop yield.

We anticipate that cover crops and mechanical weed control will reduce the incidence of weeds in flax and result in greater profitability. This information will increase organic flax profitability and reduce production risk, ensuring Canada remains competitive in flax production.

Materials and Results to Date

• • Presented on the POGI Conference Call, 2018
    
• The People Behind the Research: A Conversation with Dr. Steve Shirtliffe
  
  • OACC and OFC. 2015

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