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Air Seeders & Sunflower

Monday, March 28, 2011
filed under: Planting Systems

Many sunflower growers utilize an air seeder/air drill to plant this crop in a solid-seeded fashion. Through the years, one “knock” on using air seeders for a low-seed-volume crop like sunflower has been inadequate consistency in seed placement, resulting in more clumps or gaps of plants, compared to a row-crop planter.

However, the narrower-row spacing of many air seeders/drills likewise does provide the opportunity for a higher degree of seedbed utilization, allowing for good success with a more-randomized seed distribution system.

Most air seeder manufacturers have made their units more “sunflower friendly” than they used to be. Horizontal separation may not be as defined as that with a properly operating row-crop unit; but overall, depth control, trash clearance, operating widths and tank sizes make air seeders an attractive option for numerous producers. Below, two manufacturer representatives answer two questions pertaining to optimizing seed placement with their air seeders.

What basic calibration steps/procedures do you recommend growers take prior to heading into the field to plant sunflower?

Perry Weisberg / Bourgault Industries — Most sunflower seed recommendations are given in plant counts or populations per acre. Sunflower seeds vary in size, so a seeding rate based on weight must take into account seed size. It’s important to calculate a pounds-per-acre rate of seed based on the number of seeds per pound and the desired population per acre. This will generally calculate out to a seeding rate of roughly 3 to 4 lbs/ac.

Once this rate is established, the PDM metering system can be very easily set and calibrated to ensure the precise amount of seed is being applied. All Bourgault air seeders utilize a hydraulic calibration system, allowing the operator to accurately verify seed rates before going out to the field. This results in a very accurate delivery rate with no surprises with seed shortages or overages.

Randy Ellis / Morris Industries — Prior to calibration, it is important for the farmer to know his “targeted pounds/acre seeding rate,” taking into account (1) targeted plants per acre, (2) seed count per pound and (3) anticipated germination rate. We have outlined the calibration procedure in our operator’s manual, and it walks the operator through the necessary steps. Also, our air tanks have charts on them to assist in starting the calibration procedure.

Due to the pressures of the seeding season, it can be very easy to cut corners or not effectively calibrate your seeding system. A little extra time prior to seeding can ensure you have a very satisfactory plant stand.

Beyond calibration, what additional steps should sunflower growers take to help achieve optimum seed placement and a more-uniform plant stand with your units?

Weisberg — Research is proving that fertilizer placement — particularly nitrogen placement in relation to the seed — is vitally important in the yield potential of the crop. If an air seeder is used to place all of the sunflower crop’s nitrogen requirements in a single pass with the seed, it is very important to provide adequate separation between the nitrogen band and the seed row.

Generally speaking, nitrogen rates of greater than 40 lbs/ac need to be positioned at least 3-4” away from the seed row to ensure emergence and vigor are not adversely affected by the high concentrations of nitrogen fertilizer. The mid-row bander is available on all Bourgault seeding platforms.

Phosphate placement is also important and is generally best positioned with the seed, as early season access to this nutrient is critical. With up to four separate compartments on Bourgault air tanks, multiple products can be metered and delivered either within the seed row or through the unit’s mid-row bander.

Optimal packing of the soil over the seed row is another factor that can play a significant role in obtaining uniform, healthy emergence and vigor — especially with sunflower.

Ellis — Once you have the depth set and the unit calibrated, seeding speed is an important consideration. At Morris, we believe in effectively managing your speed so that you do not compromise your seedbed. We only get one chance at seeding time, so slow down and make sure you do it right.
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