Crop & Pest Report


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Flax Production (4/26/12)

Based on the USDA projected acres to be planted in 2012, there will be 260,000 acres in North Dakota, an increase from the number of acres planted in 2011.

Flax table

Flax varieties need to be selected based on their yield potential, resistance to lodging, and their tolerance to diseases like Pasmo, rust, and wilt. Pasmo is a Septoria disease that infects stems which often girdle plants during a wet August. This girdling promotes lodging, which may result in reduced yields and poor seed quality. There are both brown and yellow seeded varieties of flax. The yellow seed coat variety ‘Carter,’ released by NDSU, has a good yield potential, good oil content, medium maturity, and has resistance to rust. It is also tolerant to flax wilt. Resistance to lodging in a variety is important especially if direct harvesting is considered as compared to swathing.

Seeding rate for flax is in the 35 to 50 lb per acre range with lower rates in drier regions. About 80 established plants per square foot is a good to excellent stand. Higher seeding rates will insure uniform ripening which is important for straight combining the crop. Flax figure

Seedbed preparation for flax is similar to canola. The minimum soil temperature for germination is 45-50 °F, which is slightly higher than for canola or field pea. The seeding depth is 1 inch. Farmers should avoid seeding deeper than 1 ½ - 2 inches as this may lead to poor stand issues, especially when there is soil crusting. No-till flax has performed very well.

Yields dropped dramatically as flax was planted later in the season. Eight years of data at Minot demonstrated the loss of yield with a later planting date. The highest yields were obtained with early May planting. Planting the first week in June resulted in yields of only 68% compared with early planted flax. Flax, like any other cool season crop, responds well to early planting as the flowering will take place during cooler temperatures and the duration of flowering may increase.

Frost seldom kills flax seedlings. Just emerged seedlings can tolerate a temperature of 27 °F and after the plant has 2-3 true leaves temperatures in the lower 20’s °F can be tolerated if these temperatures are not maintained for a long period of time.

Flax responds to nitrogen fertilizer. As with any crop, adequate nitrogen will result in optimum yields, however high N levels may stimulate vegetative growth and increase the potential for disease and lodging. The general recommendation is a base rate of 80 lb actual N per acre. The base rate needs to be reduced by a N credit for a previous annual legume as well as by the lb N indicated in the soil test (0-24 inches).

Flax is relatively unresponsive to phosphorus fertilizer. Flax plant roots have a relationship with mychorrhizae and this helps the plant to utilize soil available P.  Potassium should be applied according to the soil test and yield goal (see link below).

Flax generally is in a vegetative period for 40 to 50 days following planting. The flowering period can be up to 25 days depending on the weather conditions during flowering. Once the bolls have formed and fertilization has taken place, seeds will mature within about 35 days.

Flax tolerates fall frost very well and is resistant to shatter unless there happens to be a heavy Pasmo infection in the field. Pasmo can girdle the petals holding the boll and the boll may drop if harvest is delayed due to a long period of rain. Generally producers have a couple of options when harvesting flax. Swathing has been practiced for many years and is still used when weed growth is excessive and swathing is necessary to dry out the weeds for combining the flax seed. If the field is clean, many producers have gone to swathing and harvesting right behind the swather.  As flax is swathed, it is susceptible to blowing. Each year there seems to be a problem with flax blowing causing it to roll up and shell out and often fields are rendered unharvestable if blowing is excessive. When swathing, use a roller to press the flax straw into the stubble. Flax is very tolerant of rains and flax dries up generally quickly following the rain. Flax can also be direct harvested. Pre-harvest treatment of flax with a pre-harvest herbicide is possible. It is important to treat when the seeds are turning color, from green to brown, and are loose from the boll. That means they are physiologically mature and any yield losses caused by application of a burn down herbicide will be minimal. Do not apply glyphosate to flax grown for seed because it may result in reduced germination of the seed and low vigor.


Web resources:

Flax Production in ND

Growing flax (Canadian pub.)

North Dakota Fertilizer Recommendation Tables and Equations


Hans Kandel

Extension Agronomist Broadleaf Crops

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