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Published May 27, 2014, 09:23 AM

Flax potential exists in SD

BROOKINGS, S.D. — Today, only about 7,000 acres in South Dakota are planted with flax seed. This is a large change from the mid-1980s when South Dakota produced close to 100,000 acres of flax and was one of the largest producers in the U.S., according to Ruth Beck, South Dakota State University Extension agronomy field specialist.

By: SDSU Extension Service , Agweek

BROOKINGS, S.D. — Today, only about 7,000 acres in South Dakota are planted with flax seed. This is a large change from the mid-1980s when South Dakota produced close to 100,000 acres of flax and was one of the largest producers in the U.S., according to Ruth Beck, South Dakota State University Extension agronomy field specialist.

Flax seed has increased in popularity in recent years because of its high dietary fiber and its high omega-3 oil content.

Flax 101

Flax produced in South Dakota is typically used for feed, food or oil.

There are varieties with yellow seed and others with brown seed. “Some markets discriminate on seed color, while others don’t,” Beck says. “Flax works well in a crop rotation with small grains and corn.”

South Dakota flax is also often a popular component of cover crop mixes because it attracts pollinators and has strong arbuscular mycorrhizal associations.

Research has shown that meal made from flax that has had the oil removed by solvent extraction or cold-pressing makes excellent livestock feed.

For optimum yield and disease control, flax should be in a three-year or more rotation. Beck says producers should select a variety that is adapted to their location. SDSU has flax variety performance results from 2012 and previous years available on iGrow.org.

Moisture requirements

Moisture requirements for flax are lower than many other crops including wheat, corn and sunflowers. The root system on flax is primarily located in the top 2 to 3 feet of the soil. Consequently, Beck says flax does better in medium and heavy textured soils that hold more water in the surface layers.

“Flax is highly mycorrhizal, meaning it can extract maximum amounts of water from the zones where its roots grow if it is in a diverse no-till rotation favoring VAM (vesicular arbuscular mycorrhiza),” she says. “This ability to dry the surface soil sometimes presents more of a challenge in establishing a winter wheat stand in the fall, as compared to where peas are grown. The excellent snow-catching ability of flax stubble provides a distinct advantage in recharging soil water prior to spring.”

Planting recommendations

Flax should be seeded at ¾ inch to 1 ¼ inches deep.

“Be sure to plant only high-quality seed with good germination. Certified seed is recommended to assure varietal purity, seed viability and freedom from pathogens and weed seed,” she says.

Seed treated with a fungicide can reduce seed decay and seedling blight and increase stand significantly. Some published fact sheets on flax production recommend seeding rates be between 25 and 45 pounds per acre. In fact, Beck says, experienced flax producers in central South Dakota and the SDSU Oilseeds group usually seed flax at rates around 50 pounds per acre.

Vulnerable to frost

Flax is epigeal upon emergence, meaning it places its growing point above the soil surface (or above crop residue). This makes it vulnerable to spring frosts, Beck explains.

“High residue conditions actually enhance this issue for crops like flax. Residue reduces frost issues with crops that keep their growing point below the residue-soil surface (peas, small grains, corn) until later in their growth cycle. This means flax is normally seeded later than peas and wheat and before corn,” she says.

When seeding with disc drills into no-till, it is important to measure the distance of the seed into the soil.

“Some producers tie up their closing wheels when residue levels are heavy, leaving the flax pressed into the bottom of a trench that is not fully closed. High residue farming systems minimize issues with surface crusting. The small seed size of flax means it is vulnerable to surface crusts,” Beck says.

Flax is sensitive to seed-placed fertilizers. It is more sensitive to zinc deficiency than many crops. Like most oilseeds, it requires sulfur.

Herbicide recommendations

Herbicide options are included in the 2014 South Dakota Pest Management Guide for Alfalfa and Oilseeds. There are several herbicide options (bromoxynil, MCPA, and clopyralid and combinations) that provide opportunities to break resistance cycles that develop in wheat, corn and soybean production.

Life cycle of flax seed

The life cycle of the flax plant consists of a 45- to 60-day vegetative period, a 15- to 25-day flowering period and a maturation period of 30 to 40 days. Flax maturity is usually judged by the color of the bolls. Beck says typically flax is harvested when 75 to 90 percent of the bolls are brown.

During the ripening process, under certain conditions, stems might remain green and a second flush of flowers might even occur. Desiccants can be used to accelerate the drying after the crop is mature (70 to 80 percent of bolls are brown; seed moisture 30 percent or less) and might be beneficial especially in fields that contain a lot of weeds.

Grasshoppers can be an issue with flax, especially during boll development and ripening stages. Sanitation practices on field borders can be very important in preventing problems.

Flax can be straight cut with a platform or stripped using a stripper header. Swathing is an option but is not common anymore. Desiccants can aid this process.

For more information on growing flax, visit www.iGrow.org.

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