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Planting Sunflower with an Air Seeder

Tuesday, January 1, 2008
filed under: Planting Systems

Editor’s Note: Using air seeders or air drill systems to plant sunflower is far from new. Some growers did so back in the early to mid-1980s, and it’s now quite common in certain growing areas. In the 2006 National Sunflower Association crop survey, for instance, nearly half of surveyed fields in North Dakota were in row spacings of less than 20” — suggesting they were planted with an air seeder or air drill.

Saskatchewan-based Bourgault Industries is one of several manufacturers whose air seeders and drills are used to plant sunflower. In the following remarks, Ron Allan, general manager of Bourgault’s Minot, N.D.-based U.S. division, addresses several questions posed by The Sunflower.

What special challenges are posed by sunflower seeds, due to their irregular shape and the low seeding volume?

The Bourgault air seeder uses one metering auger per tank to meter product. The rate of application is determined by the speed the auger turns. These augers are designed with a large capacity to handle very large seeds and/or high rates. Sunflower seeds pose no issue at all. The metering auger is simply slowed to a speed that delivers the correct rate.

Years ago we used to hear about seed depth placement inconsistencies when using an air seeder for sunflower. How has that been addressed with the newer models?

Many of the new toolbars designed to be used with air tanks have much-improved contourability. Design features ranging from floating hitches to independent depth control openers follow the surface of the field much closer than early converted tillage units.

Some folks suggest sunflower seed-to-soil contact and depth control are not adequate when using the wider sweeps (8” or more). What are your thoughts on that assessment?

The seed-to-soil contact challenges experienced when using wide sweeps were more a result of insufficient packing as opposed to poor seed placement. In this type of system we often used coil packers or rolling baskets to firm the soil that had been tilled during the seeding operation.

What we have seen changed is most sunflower is now sown with a much narrower tip where on-row packing can be achieved. This has increased seed-to-soil contact and improved emergence significantly, especially in dry conditions.

How do you recommend that growers calibrate their Bourgault units for planting sunflower — i.e., the process prior to heading to the field?

All our seeding units are equipped with charts that instruct the operator on where to set the unit for the desired seed rate. Once the initial setting is complete, we then utilize our powered stationary calibration system where the metering system is turned via a hydraulic motor until the sample box is filled. (This is all standard equipment.)

Once the box is filled, the sample is weighed and the weight entered into the air seeder monitor. The monitor then calculates the actual application rate. If the application rate is correct, the seeding operation begins. If the rate is not correct, the operator begins the seeding operation and adjusts the rate from the tractor cab.

Are there additional steps growers should take to achieve the best possible seed placement and a uniform plant stand?

Proper fan speed is very important. Because the seed rate is typically lower with sunflower than many other crops, the operator must ensure he adjusts the fan speed accordingly. Too high a fan speed can affect seed placement.

Seeding on a 20” row spacing is another option we have seen many of our customers use when seeding sunflower with our units. Again, fan speed is an important setting.

Seeding speed is also an important consideration. As soil types and conditions vary, so should ground speeds. With narrow-row spacing, soil can “step” from one row to the other, leaving more soil covering the rows seeded by the drill’s front row. Maintaining an even amount of soil over each row will contribute to even emergence.

Any other comments pertaining to the use of your units to plant sunflower?

With the ability to direct seed into standing stubble, we often find our units seeding sunflower directly into many different types of residue with low-disturbance openers. We’ve also seen many different crops seeded into sunflower stalks with our drills.

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