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Grain Yields Benefit From Sunflower in This Rotation

Wednesday, January 1, 1997
filed under: Rotation

So you say your small grain yields suffer following sunflower . . . that the ’flowers suck out the moisture or use up the nutrients — or both — to the detriment of the succeeding cereal crop?

David Kyle brings a different perspective to the discussion table. Standing in a harvested spring wheat field that averaged 47 bushels per acre in 1996, the north central North Dakota grower points to a second wheat field across the road. That one — just yards away and seeded on the same day — ran about 40 bushels. The only difference was their preceding crops: spring wheat on the 40-bushel field; sunflower on the neighboring 47-bushel field.

Such an outcome is no exception to the rule for Kyle, who farms with brother Bill near Bottineau, N.D. Over the past decade, the Kyles estimate their spring wheat, durum and barley yields following sunflower have averaged five to seven bushels higher than those coming on the heels of another grain crop.

What’s behind this story? David Kyle attributes the results to two main factors: (1) increased moisture retention due to a no-till regimen between sunflower harvest and the next year’s grain crop; and (2) less disease — particularly scab — in the cereals when following sunflower rather than a crop susceptible to the scab fungus.

The Kyles’ grain-on-’flowers program starts during the sunflower harvest. They prefer leaving the stalks up to two feet in height for snow trap; but if there are lodged spots or hanging heads, they won’t hesitate dropping their row-crop header to retrieve them. Their combine is equipped with a “Redekop” chaff spreader which gives them a uniform 30-foot distribution pattern — another important facet of their no-till approach.

Other than soil testing, that’s it until spring. “We’ll then spread our urea according to the soil test and plant the field to a cereal crop — either durum, spring wheat or barley,” Kyle says. They use a 45-foot 8500 Case IH air drill equipped with Eagle Beak openers set on seven-inch spacings. The Eagle Beak shoe provides sufficient incorporation for the urea so it won’t degrade if rain is not promptly received, he notes. Despite its higher price tag compared to anhydrous, Kyle believes the minimal soil disturbance — i.e., less loss of moisture — makes the urea a worthwhile investment.

Carryover of Treflan from the sunflower season spreads out the cost of weed control over two crops and, in some years, allows the Kyles to forego the standard preplant Roundup application on their grain ground. “We’ll usually spray before the two-leaf stage for volunteer sunflower,” David adds.

Drilling no-till grain among the standing sunflower stalks is not a problem. Traveling parallel to the sunflower rows, “we tear out very few sunflower roots when seeding grain,” Kyle notes. “Whenever those roots are pulled out, you’re opening up ground and losing moisture.

“Sometimes people look at you ‘cross-eyed’ in the spring when you plant into those standing stalks,” he quips. “But I tell them to come back in about six weeks and look at it.” Nor do the undisturbed sunflower stalks cause problems for Kyle during the grain harvest. Many are still standing as he swaths his grain, but they’re brittle and easily cut.

While the Kyles laud the importance of inserting sunflower between grain crops to aid with disease control in the cereals, they simultaneously try to keep a healthy interval between sunflower crops for the same reason. They prefer planting ’flowers no more than one year out of five on a field to minimize risk of Sclerotinia.

On no-till grain ground going into minimum-till sunflower, it’s typically mid-May by the time the Kyles apply their preplant treatment of Roundup. Anhydrous and 10 pounds of Treflan granules go on 10 days to two weeks later. That pass is followed the next week by a second incorporation pass and seeding of the sunflower with their 950 Cyclo. The past two years, most of their ’flowers have been seeded during the first week of June.

The Kyles put down an 18-46-0 blend at planting, typically fertilizing for a 1,500-pound yield goal. Despite their northerly climate and inclination toward late seeding, they usually meet or exceed that goal, with their best crop (1994) averaging just over a ton per acre. — Don Lilleboe
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