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10 years Growing No-Till ‘Flowers

Saturday, December 1, 2001
filed under: Minimum Till/No-Till

10 years Growing No-Till ‘Flowers

The time has given High Plains producer a yardstick to test reasons behind his rotation practices

There were primarily three reasons why Rick Lewton began experimenting 10 years ago with no-till sunflower in his crop rotation: 1) the belief that he could improve seedling emergence over that of conventionally-raised ‘flowers; 2) hopes of better yields due to enhanced moisture retention; and 3) with the wheat stubble, being able to retain more crop residue following sunflower harvest, thereby aiding erosion control during the subsequent fallow period.

His first year with no-till sunflower wasn’t exactly the best litmus test to evaluate the moisture value of no-till. Lewton’s northeast Colorado growing region averages around 15 inches of annual total precipitation, and in 1991 the area received over 17 inches of rainfall between April and September.

However, Lewton and many growers in the High Plains know all too well that moisture has been hard to come by the last few years. That’s why sunflower continues to be a part of the crop rotation on Lewton’s farm near Otis, Colo., and in the cropping systems of other High Plains growers.

“It’s been a good crop for this area, and processors have recognized that too,” says Lewton, crediting greater planting flexibility allowed under the 1996 Farm Bill for allowing sunflower to find a niche in the High Plains. “Sunflower is well-suited for our climate, relative to other crops, in that they can get by on limited rainfall. We generally don’t have the bird and insect problems to the extent of some areas of the Dakotas, although we do need to scout and spray for the head moth and seed weevil. And as long as we do a good job with adequate rotations, disease potential should continue to be minimal.”

Lewton’s crop rotation generally is winter wheat, corn, sunflower, then proso millet, spring wheat, or fallow, depending on moisture. “We prefer continuous cropping, but because of the moisture, it doesn’t always work out that way.” Lewton generally grows confection sunflower, which has greater profit potential. “The confection industry has grown here, to the advantage of the producer,” he says.

The lack of weed control options was a drawback for Lewton to produce sunflower 10 years ago, and it continues to be a problem now, best managed by crop rotation. He says Spartan has been a welcome weed-fighting addition, however, in helping to control small-seeded broadleaf weeds, including kochia, pigweed, lambsquarters, and nightshade. “You just need to be aware of the soil types you’re using it on. It’s a bit of a discovery process on what rate and timing is best for different fields. And it still needs to be rained in.”

Lewton broadcast applies Spartan several weeks before planting, and applies glyphosate to control early weeds a minimum 10 days before planting.

Ron Meyer, Colorado State University extension agronomist, Burlington, Colo., says sunflower damage is indeed possible with Spartan used at the higher end of recommended label rates (4-5 oz.), particularly on high pH soils. However, he points to plot trials in which Spartan was tested on 15 sunflower hybrids using Spartan at both 2 and 3 oz. rates. The result was good weed control and no herbicide injury. In soils with a pH of 7.5 or higher, use the 2 oz. rate, Meyer recommends, and apply Spartan well ahead of planting, up to two weeks beforehand. That’s worked well in giving good weed control with little risk of injury in both no-till and reduced till systems, he says.

Ten years has given Lewton plenty of time to evaluate the reasons why he started growing no-till sunflower:

Seedling emergence—“Most years we’ve generally had enough moisture close enough to the soil surface to get sunflower going and established in a timely manner. With conventionally-planted sunflower, you need more rain to get them going,” says Lewton.

Yield— Lewton’s sunflower yield has generally been enhanced by no-till. In 2000, which saw record heat and dryness, seed size was small but yield was only off about 400 to 500 lbs/acre from a yield average that would generally be around 1,500 lbs/acre. This year, Lewton’s sunflower yield averaged about 1,550 lbs/acre, ranging from about 1,350 to over 1,700 lbs, despite another year of less than desirable growing conditions.

Field residue—No-till has indeed helped with soil erosion control in fields going into fallow. “That’s generally every four to six years, but it varies. You have to be very flexible in your rotation, is what it comes down to. Changes may be needed depending on the moisture situation.”

Lewton has bumped up his plant population since his early years of sunflower production, from a seed drop of about 13,000 plants per acre, to about 14,000 plants per acre. The higher plant population helps reduce weed pressure, he says, and allows for higher yield potential in years when there is greater than average rainfall.

Even though Lewton might be called an old hand at growing sunflower now, he still experiments with different practices. For example, he has begun using Keaton seed firmers with fertilizer tubes for applying starter fertilizer, instead of conventional fertilizer openers mounted on the front of the planter.

“Better seed to soil contact through use of the Keatons improves stand establishment of the sunflowers,” says Lewton. The Keaton furrow closures firm the seed below the starter fertilizer in the row, he explains. This allows for better seed placement by eliminating the fertilizer disk disturbance, as well as less residue plugging problems that can occur with front-mounted fertilizer openers.

Lewton applies the balance of his nitrogen by dribbling 32% N with a spray rig prior to planting. “You do need to keep N rates low when applying the starter in the row, especially with sunflower so that seedling damage doesn’t occur,” he says. “I have used a 4 or 5 gallon per acre rate of 10-34-0 in the row successfully, which equates to about 4.5 to 5.7 pounds of N per acre. Higher N rates can damage the seedling. I do not use any additional nutrients such as sulfur in the row, because it can be damaging to seedlings.” – Tracy Sayler

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