March 18, 2013 Deciding Which Flax Variety to Seed

Deciding Which Flax Variety to Seed

Oilseed flax has a significant percentage of long tough stem fibers that decay slowly over time. This makes it difficult to incorporate flax straw into the soil after harvest since the fibers wrap themselves around and/or plug disks, wheels and shovels. In the past, coping with flax straw included dropping it in windrows after the combine and burning or harrowing and/or raking it into piles and then burning it. Today, this practise is discouraged for a number of reasons:

1.     It may have a damaging effect on air quality and human health;
2.     It can increase the risk of soil erosion and soil degradation;
3.     It will destroy any possible economic value of the straw;
4.     It presents safety concerns related to open fires

To help raise awareness of alternatives to burning flax straw, the Saskatchewan Flax Development Commission (SFDC) is working with Agriculture & Agri-Food Canada on an Agri-Environmental Group Plan (AEGP) for straw management. In deciding how to manage their straw, producers need to consider two streams of alternatives:

•     Stream 1: Minimizing problems with straw residue in the field.
•     Stream 2: Utilizing the straw as a source of fiber.

Variety Selection by Fiber Content

Many factors influence the quantity and quality of flax straw produced on a given field in any given year. One of these factors is which variety is seeded. Some flax varieties are known to have a lower or higher fiber content relative to others. The relative amount of fiber in the flax straw may impact whether a producer chooses to chop and spread their flax straw, or whether they decide to bale it and sell it.

The following list shows the fiber content of the most commonly-seeded flax varieties.

Main characteristics of Flax Varieties, 2006

Data from Regional and Coop yield trials grown over a number of years. Fiber contents from plots grown in 2003, 2004 and 2005.
**Relative Maturity: The relative maturity of the check, CDC Bethune, is L (on average 101 days from seeding to swathing ripeness).
Additional information:
Index is using Bethune = 100
All varieties are resistant to rust and moderately resistant to Fusarium wilt.

The above data was generated from testing the fiber content of hundreds of straw samples collected from twelve test sites in regional variety trials over a three year period.

Implications for minimizing residue problems or utilizing the straw as a source of fiber

•     Growers who wish to minimize problems with straw residue may want to consider seeding a lower-fiber content variety to make it easier to chop and spread their straw after harvest.
•     Producers wanting to maximize net returns from the sale of their flax straw for fiber extraction may want to seed oilseed flax varieties with higher fiber contents.