1. Variable Rate Seeding Technologies

2. Definition
Variable rate seeding is practice of planting varying crop populations based upon yield potential.

3. Why vary the population?
Variation in yield potential due to:
Soil type/water holding capacity.
Soil pH.
Depth of soil profile.
“Due to spatial variability optimal dryland corn population in Oklahoma can easily range from 18,000-22,000 plts/ac in a single field.” Michael Marlow, Dekalb / Asgrow Area Agronomist.
On farm research potential.
Plant strips of varying population and yield check to find optimum population for area.

4. Components Data to base seeding rate upon.
Prescription map generating software.
Variable rate controller.
Variable speed planter drive and control.
GPS receiver.

5. Process
Determine basis for adjusting population and generate prescription maps.
Load maps into rate controller.
Rate controller sends desired planter drive speed to drive controller.
Drive controller varies hydraulic flow at the hydraulic motor on the planter transmission.

6. Data Flow AgLeader Pf Advantage Rate Controller www.agleader.com
Population Prescription
Rawson Hydraulic Variable Speed Planter Drive
Rawson Planter Drive Control

7. Advantages Reduced seed cost.
Yield may actually increase in drought prone regions of field due to less biomass.
May allow more acres to be planted when seed is limited.
Flat rate population is infinitely adjustable.

8. Example Economic Return
Seed Savings
Double-stack hybrid - $190 / 80,000 sds = $ /sd
$ /sd * 4,000 sds/ac = $9.52/ac savings
$9.52/ac *0.5 (low population not needed on all acres) = $4.74/ac

9. Example Economic Return
System cost - $7,150
FarmTrac and Farmsite - $600
AgLeader Pf Advantage - $2,400
Rawson Drive and Controller - $4,150
Breakeven - $7,150 / $4.76/ac = 1,502 ac
NOTE: This budget is intended for adjusting only for low producing areas and does not account for yield boost due to reduction in foliage overgrowth.

10. Disadvantages Initial cost Increased operator requirements
More equipment = Greater chance of problems during planting

11. Conclusion
Variable rate seeding technology will most likely benefit those with large in field spatial variability.
However, for the technology to work one must identify the variability and determine the correct population for each area.
Planter operators must be able to use the equipment.

12. Questions?