Saskatchewan farmers grow the vast majority of flax in Canada. In the last decade the area planted to flax in the province has ranged roughly between 500,000 to 1,000,000 acres (200,000 to 400,000 ha) with a potential straw yield of 1100 to 3300 lbs (0.5 to 1.5 tonnes) per acre depending on the soil zone and growing season weather. This gives a potential total production of straw of 100,000 to 600,000 tonnes per year with an average year with average weather conditions about 300,000 tonnes. At the present time much of this straw is not only not used but is a challenge to expanding flax acres since it is very fibrous and generally a hassle to either chop and spread or burn. In other parts of the world flax generates an additional good income or even a very high income per acre for farmers. In those countries the straw is broken down into fibers and shive (i.e., the non-fiber part of the stems). These in turn are made into clothing (linen and linen blends), insulation, erosion and weed control mats, plastic composites, specialty paper, landscape mulch, pet bedding and bio-fuel. What wrong with our Saskatchewan flax straw and why isn’t it used more?
Flax in Saskatchewan is grown for its seed (i.e., linseed) which is generally exported and crushed for oil (linseed oil) and meal (linseed meal). The oil is used in the manufacture of a variety of industrial products and especially in oil-based paints and stains and in authentic linoleum (floor covering). The meal is used for animal feed, especially for dairy cows. Ten to fifteen percent of flax seed is ground and eaten directly by humans and animals for its heath giving effects.
In Saskatchewan, when flax is harvested for seed, almost all the straw is fed into the combine (harvesting machine) along with the seed “bolls” (capsules). The mechanisms inside the combine crush and tear the straw and seed bolls to release and latter clean the seed. The seed is retained in a hopper in the combine; the crushed, torn and broken straw is expelled out of the back of the combine and falls into a row behind the combine or are chopped and blown in a wide arc behind the combine. This results in straw and/or rough fiber that is often short and/or of irregular length and often with some exposed fiber. It also reduces the salvageable yield of straw by about half due to many bits if straw that fly away when the straw is dropped behind the combine in a row.
This type of straw is very hard to extract useful fiber from. In the past, several companies collected this straw, put it through a hammer-mill, roughly separated the fiber from the non-fiber, shipped the fibrous material to pulping facilities in the USA where it was treated with harsh chemicals that dissolved all the non-fibrous material and then used the resulting very short fiber to make cigarette papers, cellophane and celluloid however, these markets have shrunk and there are no more such flax pulping facilities in North America. Broken, damaged straw can also be used for biofuel (i.e., burning directly or making fuel pellets), outside animal bedding and soil stabilization (oil drilling sites, ditch linings, pipelines) but all of these end uses only pay farmers a small amount for their straw, usually the cost of baling plus a few dollars.
In an “oilseed” (linseed) flax variety, about 20% of the weight of the straw is made up of useful cellulosic fibers. These fibers are found just below the outer surface (cuticle) of the stem. Thousands of years ago, people found that if flax straw had rotted at little, the fibers could be extracted easily and cleanly from the straw. This partial rotting or decay of flax stems is called “retting” and is extremely important in the process of extracting high value fiber from flax straw.
In the last decade, experiments and field experience by Biolin Research Inc. have shown that in Saskatchewan, in most conditions, straw left standing over winter is exposed to a great variation in temperature, moisture levels, wind speeds and ultra-violet radiation. All these variations create conditions that “weather” the straw over winter and allow high quality fiber to be extracted from the straw in the spring with quality similar to that produced with a retting process.
At the present time most flax straw in the province is neither retted nor weathered and hence even if the straw is in long, intact, consistent lengths, it is mechanically not easy to extract high quality fiber from such straw and more especially if the straw has been broken in a combine and dropped in a thick row. The end-uses for unretted and/or un-weathered straw are similar to those described above (e.g., biofuel, specialty paper, rough ground cover) all of which pay farmers relatively little. Hence, having longer, intact consistent straw lengths and allowing it to ret or weather would have a very significant effect on increasing the potential use and value of flax straw in Saskatchewan. The next blog will provide explanations of how this can be done in a very cost effective way.
