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Six tips for better flax agronomy

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Increase flax yields with new genetics and the latest agronomy recommendations

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Photo: Flax Council of Canada

For years, flax has been the ugly stepsister to Cinderella crops such as canola. But with the right agronomy and new varieties, flax might be the belle of the ball.


The long-term Canadian average yield for flax is roughly 21 bushels per acre, said Rachel Evans, agronomist for the Flax Council of Canada. Improving flax production is largely about stabilizing yield fluctuations year-to-year, Evans told the audience at the Saskatchewan Oilseed Producers meeting. The meeting was organized by SaskCanola, SaskFlax, and the Saskatchewan government, and held in North Battleford on November 17.


Flax yield is influenced by the plants per square metre, the bolls per plant, and the seeds per boll. Ten seeds per boll is the physiological maximum, but farmers are more likely to see six to eight, said Evans. wFarmers looking to bump yield should focus on increasing the plant stand and the number of bolls per plant. 


“They are affected by our management practices and they’re also affected by the environment,” said Evans.


Related: Flax agronomy in spotlight

1. Review varieties

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Photo: Lisa Guenther

Over the next couple of years, CDC Glas will be phased in as the new check variety, said Evans. “And for me, that shows the confidence the industry has in this variety. It’s been higher yielding, performing well in all of our soil types.” 


CDC Glas isn’t the only new flax variety to be registered in the last few years. Crop Production Services, Agriculture and Agri-Food Canada, and the Crop Development Centre have recently registered new varieties. Some of the new varieties mature a little more quickly than the current check, CDC Bethune. For example, Evans suggested farmers with shorter growing seasons look into CDC Plava, a new variety that matures two days earlier than Bethune. 


How can farmers select the best variety for their areas? For Saskatchewan farmers, the Sask Seed Guide is one of the best tools, said Evans. The seed guide compares each registered variety, and compares the yield percentage to the check. Saskatchewan farmers can download a current seed guide from saskseed.ca/seed-guides. Alberta producers can find variety info at seed.ab.ca, and Manitoba farmers at seedmb.ca.


Crop insurance data is also useful, said Evans. For example, Sask Crop Insurance data is available at saskcropinsurance.com/resources/smp. It shows five-year average yields for each variety, average yields for each year, and the acreage that year. Before Sask Crop Insurance reports on a variety, it needs to have been grown by at least two farmers over at least 400 acres. However, Evans noted that if the acreage is low, the effect of an individual farmer’s management practices could skew the results.

Related: Lower Prairie flax production, decent quality expected

2. Check your seeding rate

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Photo: File

Research done in Saskatchewan and Manitoba has found that the ideal plant population is 300 to 400 plants per square metre, said Evans. That works out to 30 to 40 plants per square foot.


Flax can offset lower populations by developing more bolls per plant, said Evans. But it can’t compensate to the same extent as canola. However, plant populations higher than the recommendations don’t provide consistent benefits, and can promote lodging, she added. 


Evans recommends using a seeding rate calculator to take into account germination, thousand kernel weight, and seedling survival rates. Seeding rate calculators are available online through Alberta Agriculture and FP Genetics. 


Seedling survival will depend on several factors, such as field conditions, equipment, and fungal loads on seed. Evans suggests counting plants to see whether seedling survival came close to the target.


Related: Flax Council cautions on seed integrity

3. Seed at the right time

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The ideal seeding date for flax is sometime between the first and third weeks of May, said Evans. The farther north a farmer is, the later he should seed, she added. For example, farmers in the North Battleford area should probably target May long weekend, she said.


Like most crops, the earlier seeding dates will likely add bushels to the yield. However, Evans said, flax is more flexible with the seeding date than some crops such as oats.


Flax has good frost tolerance as long as the crop has had a chance to harden off, said Evans. Cotyledons can tolerate -3 C. Plants at the two-leaf stage can withstand temperatures as low as -8 C.


Flax is less tolerant of heat during flowering. Evans summarized a University of Saskatchewan greenhouse study that subjected flowering plants to temperatures of up to 40 C. Plants exposed to heat stress for an extended period suffered the most ill effects, including a prolonged flowering time, fewer seeds per boll, lower test weights, more flower abortions, and more shrivelled seeds. 


Farmers can mitigate heat stress by seeding earlier, she said, so the crop isn’t flowering during the hottest part of the summer.


Related: Canadian flax prospects dimmed by China’s silk road

4. Control weeds

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Flax is not competitive with weeds. And flax growers only have Group 1, 4, and 6 herbicides for in-crop weed control.


“We’ve got a really limited product range with our in-crop so let’s try to extend it as much as we can by bringing in those pre-emergent products,” said Evans. 


Ideally, farmers should control in-crop weeds early, when they’re smaller. Growers should also remember that flax is sensitive to some broad-leaf products. “So going in earlier is going to be better than going in later in terms of phytotoxicity.” 


Evans also recommended using at least 10 gal./acre of water to ensure good coverage and help prevent toxicity in the crop. 


Evans also encouraged the “many little hammers” approach to controlling weeds. Cultural practices create a more competitive crop that also yields better. Those practices include growing tall varieties, using a higher seeding rate, seeding early, and using herbicides. 


Related: The future of managing flax fibre

5. Manage disease

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Photo: Flax Council of Canada

Research out of the Indian Head Agricultural Research Foundation has shown higher flax plant populations with seed treatment, said Evans. “But we haven’t necessarily seen an increase in yield.” 


However, Evans said there are situations where the seed treatments make sense. There are three seed treatments available for flax: Vitaflo (Arysta), Insure Pulse (BASF), and INTEGO Solo (Valent). Evans said that Vitaflo and Insure Pulse are both registered for rhizoctonia and fusarium species. INTEGO Solo is registered for pythium.


Farmers who save their seed can also reduce seedling blight by reducing seed cracking at harvest. Evans suggested checking concave settings and fan speeds. 


Seedling blight isn’t the only disease issue in flax. Fusarium wilt girdles the root, preventing the plant from drawing up water, said Evans. The top of the plant will curl over, looking like a shepherd’s hook. Varieties are moderately resistant, she said, and beyond that, rotation is the best management tool. 


Pasmo is the most prevalent disease in flax. Like most diseases, it benefits from hot, humid conditions. Symptoms can appear at the seedling stage. Early on, the disease appears as brown spots on leaves. Those spots coalesce, and the leaves may drop.


Later, lesions can appear on the stems. Those lesions weaken the stems, and spread up the plant. Eventually the branches holding the bolls can weaken and break. Yield losses can range from five to 30 per cent.


Evans recommended scouting early and often, and using clean, disease-free seed when possible. Pasmo only infects flax, so crop rotation also helps. However, if flax is grown in the area, wind can spread the disease. 


There are also two foliar fungicides — Priaxor and Headline — available to treat the disease. “We do know that they work.”


University of Saskatchewan grad student Trisha Islam studied fungicide efficacy in flax. She found fungicides decreased disease severity and increased yield when the disease was present. 


“But, at one of her locations, where they couldn’t get the disease to show up, there was no benefit of applying fungicides,” said Evans. 


Pasmo also causes premature ripening, said Evans. Priaxor treatment delayed ripening five days compared to the untreated check. 


Islam also applied fungicide at early-flowering, mid-flowering, and both stages. Evans said there was no yield difference between applications at early- or mid-flowering. 


“So you can be scouting up until you’re about to put this product on for those spots on the leaves. And if you see them, you have a bit of a window there to get the product on,” said Evans. She noted that sometimes the mid-flowering application saw a higher seed weight. 


To time the fungicide application, Evans said farmers can watch for the first flowers. Seven to 10 days after they appear, the crop will be in the mid-flowering stage. 


Evans said research published in 2014 and 2015 shows that fungicide can also reduce lodging. The research found that more nitrogen added up to more disease, if the disease inoculum was present. But with a fungicide application, flax responded well to higher nitrogen rates, and lodged less. 


Related: VIDEO: Scouting flax crops for pasmo

6. Watch for fertility sensitivity

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Flax is a moderate nitrogen user. The current nitrogen recommendation is 90 to 110 lbs. per acre, including what’s in the soil. That’s targeting a 30 to 35 bushel yield. Evans said banding is best, as flax is sensitive to seed-placed nitrogen. 


Phosphorus is also best below or to the side of the seed row, said Evans. She recommended no more than 15 lbs. of P2O5 in the seed row. The Flax Council of Canada notes that some provinces recommend no phosphate in the seed row. The Council also notes that recent research has shown that placing nitrogen and phosphorus together to the side or mid-row doesn’t reduce the phosphorus’ benefits.


Fertilizer recommendations may change in the near future. The Indian Head Agricultural Research Foundation is leading the biggest study ever done on N-P-S-K on flax in Canada, said Evans. The research is being done at eight locations over three years. 


Farmers should avoid seeding flax into brassica stubble. Flax relies on soil fungi to scavenge phosphorus from the soil, Evans explained. That soil fungi doesn’t colonize canola roots, so there will be less of it in the soil after a canola crop. Seeding into wheat, corn, or pulse stubble works better. 


“One of the lowest-hanging fruits with flax is crop rotation, in my opinion.” 


The Flax Council of Canada has a detailed production manual available online at flaxcouncil.ca/growing-flax.

Related: Flax Council of Canada to shut office

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