Tips for a Successful Sunflower Harvest
Combine forward speed usually should average between 3 and 5 miles per hour. Forward speed should be decreased as moisture content of the seed decreases to reduce shatter loss as heads feed into the combine. Faster forward speeds are possible with seed moisture between 12 and 15%.
Slow cylinder/rotor speed to 250 to 400 rpm. Combines with smaller cylinders will require a faster speed and combines with a larger cylinder diameter will require a slower speed.
When crop moisture is at 10% or less, conventional machines should be set open to give a cylinder to concave spacing of about 1 at the front of the cylinder and about 0.75 at the rear. A smaller concave clearance should be used only if some seed is left in the heads after passing through the cylinder.
If seed moisture exceeds 15 to 20%, a higher cylinder speed and a closer concave setting may be necessary, even though foreign material in the seed may increase. Seed breakage and dehulling may be a problem with close concave settings. Make initial adjustments as recommended in the operator's manual. Final adjustments should be made based on crop conditions.
Set the fan so only enough air flow is created to keep trash floating across the sieve. Set the upper sieve at 1/2 to 5/8 inch wide. Set the lower sieve at 3 /8 inch wide.
Combine at 14-15% moisture and dry down to under 10% moisture, the recommended level for overwinter storage.
Twelve-inch pans best for 30-inch row spacings; 9-inch better for other row sizes and solid seeding.
Rule of thumb for acceptable harvest loss: 10 seeds per square foot represents a loss of 100 pounds per acre. Dont forget heads that have seed left in them. Adjust seed counts taken directly behind the combine discharge for the concentrating effect from the width of cut down to the separator width. Do this by dividing the number of seeds found by 4. In other words, in the discharge area, 40 seeds per square foot represent a loss of 100 pounds per acre.
Remember fire potential, especially when conditions are dry. Keep combine and grain dryer free of chaff and dust. Keep a small pressure sprayer filled with water on hand in the combine in case of fire. If the threat of extreme dry conditions and combine fires persists, try nighttime harvesting, when humidity levels are higher.
Source: NDSU Extension Service
When to consider a sunflower desiccant
If bird pressure is severe, disease levels are high, or lodging problems are occurring, the use of a harvest-aid desiccant for sunflower may be considered when the crop is mature and an early harvest would be an advantage.
Early drydown of sunflower plants may slow or stop development of head rot and reduce sclerotia and destruction of seeds. Desiccation can also reduce head shattering, control weeds (especially large weeds like kochia and marshelder, resulting in less dockage and less wear and tear on combines) and ease crop drying with reduced drying costs.
Desiccant and application costs must be weighed with prospective advantages. Warm sunny days following a desiccant application are needed to give the best results. Two types of desiccants can be used. These include paraquat (Gramoxone Max) and sodium chlorate (Drexel Defol) for use on oilseed and confectionary sunflower. Allow a minimum of 7 to 10 days prior to harvest to get maximum killing and drydown of the sunflower. Read and follow the label for rates and adjuvants to use.
Apply desiccant by air after the back of sunflower heads after seed moisture content falls below 35%.
Estimating Sunflower Yield
To estimate crop yield, you need to take the following into account:
Seed Size category
Good seed set
Center seed set
The following NDSU web site explains how to estimate these factors: http://www.ag.ndsu.nodak.edu/aginfo/procrop/sun/yildes08.htm
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