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Sunflowers Sizzle

They will go deep for nitrogen that otherwise may be lost.

Sunflowers are good option in the own right this year.

Prices are higher than normal.

But they can also help you cut your fertilizer bill and increase income if wet weather early in the season prevents you from planting corn, wheat, canola, field peas.

Go deep for N

Sunflowers can help you save money on fertilizer because they are great nitrogen scavengers, says Larry Kleingartner, executive director of the National Sunflower Association.

On-farm observations and university research validate the sunflower plant's ability to nab soil N too deep to be used by other crops.

A study at the USDA-ARS Central Great Plains Research Station in Akron, Colo., in the late 1990s analyzed recovery of N fertilizer placed deep in the soil profile with different placement methods. The Akron researchers found that sunflower recovered half the fertilizer N placed two feet deep. They measured 23% recovery from fertilizer N placed four feet deep, and 12% recovery at five and a half feet deep.

Drought can result in high amounts of residual N left behind in a non-leaching environment, says David Franzen, North Dakota State University Extension soil fertility specialist. For example, a soil test of a drought-stressed field near Williston, N.D., showed more than 200 pounds of nitrogen per acre between two and four feet deep in the soil profile.

A lot of soil N can be left behind in irrigated environments as well. For example, on fields in the High Plains that have been planted to irrigated corn over multiple years, it can be common to find 200 to 400 pounds of nitrate below the corn root zone, typically three or more feet deep in the soil.

As one of the deepest rooting crops, sunflower will extract residual N, provided there's not a compaction zone to inhibit root growth, and if subsoil moisture is adequate to encourage root growth.

The only way to know for sure what nutrients your fields need (or don't need) is through soil sampling analysis. Consider a deeper probe (beyond 2 ft) to get a better idea about N further down in the soil that might be there for sunflower's taking, Kleingartner advises.

Plan B crop

"Weather will obviously have a big impact on planting intentions," Kleingartner says. "A heavy rain or late spring snow can derail plans to seed early season crops like wheat, field peas or canola, as well as crops with a narrow planting window, like corn.

In those cases, sunflower is an excellent 'Plan B' crop, with a wide planting window and that ability to use residual soil nitrogen."

For more information call Kleingartner (701) 328-5103 (office) or (701) 426-6348 (cell).

TAGS: USDA Extension
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