Before you start up the combine this fall, review this checklist as a quick reminder of best practices to attain optimal yields and reduce field losses at sunflower harvest.
Get the crop off early by applying a desiccant. Natural sunflower dry down can be slow and uneven. By speeding up the dry down process, chemical desiccants decrease crop losses due to inclement weather, lodging, disease and bird depredation.
Desiccants can be applied to the crop once plants have reached physiological maturity. At this point, seed moisture is about 35 percent, the backs of the heads turn yellow, and bracts turn brown in color (R-9 stage). Applying desiccant before this stage may reduce test weight and seed quality.
Remember to check local regulations for approved desiccants.
2. PREPARE HARVEST EQUIPMENT
Minor adjustments to combines can make a big difference at harvest. Combine speed should average between three to five miles per hour.
Cylinder speeds should range from 300 to 500 revolutions per minute.
Concave settings should be open.
Use the slowest cylinder speed with the largest concave opening to reduce seed damage.
Adjust the fan to accommodate sunflower seeds, which are lighter than other grains, so that air flow keeps only trash floating across the sieve.
3. SEED MOISTURE
Sunflowers are ready for harvest when the backs of the heads turn from yellow to brown in color.
Combine when seed moisture reaches 20 percent or less – experts recommend 12 to 15 percent. Seed moisture can be brought under 10 percent by drying for storage.
Combine speed should average between five to six miles per hour. However, today’s large combines often need to travel more than 5 miles per hour to keep full – ground speed should keep the combine full for optimal threshing.
The target for seeds thrown behind the combine is less than 10 seeds per square foot, which is 100 pounds of actual yield.
Check test weight when harvesting.
Keep a clean combine to reduce fire risk. Blow the combine down at least twice daily and have fire extinguishers on hand.
All grain-drying fundamentals apply, no matter what method is being used to dry the grain.
Check drying rates as sunflowers dry quicker than other grain because there are fewer pounds of water to be removed.
When drying in a high-temperature dryer, constant monitoring is needed as the chaff, lint and other debris associated with sunflowers are highly combustible.
Typically, confection and non-oil seeds can be stored short term at 10 percent moisture content, but for long-term storage growers must dry grain to nine percent.
Oilseeds (at 40 percent oil content) should be stored at eight percent moisture, however that value is determined by the oil content. Oilseeds with higher oil contents (closer to 45 percent) should be stored between seven and eight percent.
In storage, monitor grain every couple of weeks when outside temperatures are warm and every two to four weeks in the winter months.