New retting studies to help farmers spin straw into fibre gold

Composites Innovation Centre striving to meet fibre and composite industry demand

When a European company called Ecotechnilin came to Manitoba to test hemp and flax fibres, but couldn’t use them because of their quality, Sean McKay, president and CEO of the Composites Innovation Centre (CIC), knew it was a missed opportunity.

“We can’t get higher-end buyers to take these materials for their applications because they don’t have confidence that our fibres hit their quality requirements,” said McKay.

Fibre quality was a barrier to increasing value of hemp and flax crop products and improving commercialization. The CIC, the Prairie Agricultural Machinery Institute (PAMI), the National Research Council of Canada, producers, agronomists, processors and consultants identified a process called field retting that would address these issues. With help from the Growing Forward 2 Growing Innovation program, research on field retting began in Spring 2016.

Letting nature do the work

Field retting is when microorganisms in the soil break down materials that have been left on the field, making the fibres easier to remove from the stem.

“What you’re trying to do with field retting is encourage the microbes to eat away the pectin that holds the fibres together,” said McKay. “This results in improved ease of processing material through an industrial decortication line and a fibre that has more consistent and better properties.”

This method has been part of European agricultural practices for centuries, but because of the differences in Canada’s climate, harvest season and agronomic processes, each province or region has to develop its own set of best practices.

“We’re just starting down this path in North America,” said Lorne Grieger, the agriculture project manager for PAMI. “Instead of taking the straw directly off the field after the combine goes over it, [field retting] lets the environment do some of the work.”

Overcoming climate concerns and conclusions

Findings from initial trials showed that field retting is possible in Manitoba and Saskatchewan, despite some challenges created by the cold climate, and that early planting and harvesting are crucial.

Eric Liu is the Manager of Foresight and Analysis for Manitoba Agriculture. Liu said Manitoba’s cold climate doesn’t pose a problem for the process since there are seed varieties available that have a shorter growing season, which is necessary for field retting.

Another finding is that pre-processing straw using a macerator or hay machine before field retting is not required and not recommended as it can degrade the overall quality of the fibres and results in bales that are difficult to untangle.

Tim Barkhouse, a hemp farmer from Roseisle, Manitoba who participated in the first set of trials in 2016, agreed and said “the more you work with hemp straw, the worse it is to deal with.”

Turning burning bales into fibreglass and non-woven mats

So, what is being done with flax and hemp straw in the meantime? According to McKay, there is a company in Alberta called the BioComposites Group that is turning natural fibres into a mat form to replace fibreglass in composite applications and other companies are incorporating fibres in green building materials, such as hemp reinforced cinder blocks.

Other mainstream commercial applications include paper manufacturing, horse bedding and/or pelletizing leftover flax or hemp materials for bioenergy - but none of these options offer maximum value to the farmer. Barkhouse said he was bailing and burning his hemp straw before he signed on to have it tested.

With a higher quality product, Manitoba would be able to welcome companies like Ecotechnilin to set up processing plants, and producers could sell their straw for biocomposites or textiles that offer greater returns.

“It takes a lot of effort to understand the dollar values attached to new techniques or processes. What do they mean for a producer like Tim Barkhouse who’s looking to maximize the revenue from his land?” said Grieger.

Figuring out the future of field retting in Manitoba

As for the future of field retting in Manitoba, many more seasons of field trials and rounds of fibre quality testing are necessary before conclusions can be reached. Further field trials and testing was conducted in 2017 and as new knowledge is generated this will be passed on to the producers.

Liu said Manitoba is on the leading edge of research and innovation for the commercialization of natural fibres.

“In Manitoba, we have one commercial fibre processing operation with two more coming soon. The CIC also leads the National Biomass Quality Network, which is working on developing a grading system for natural materials. We want to be able to grade fibres just like we grade grains,” said Liu.

With more technology in the works and a growing interest in commercial opportunities, flax and hemp farmers should keep an eye out for the results and shifts in demand.

“Growers are trying to maximize the value they can get out of their land. If we can figure this out there would be uptake,” said Grieger. “One year of data is only an indication of potential.”