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Maturity is critical for desiccation and harvest.

Agronomy Bulletin 50 ─ Sunflower Harvesting

Situation

Sunflower maturity must be determined to accurately time desiccation and harvest. Applying a desiccant to sunflowers at physiological maturity can help flowers dry down faster, enabling earlier harvest. Desiccating also can help avoid rot issues and reduce the time the crop is vulnerable to birds.

Factors to Consider

  • Maturity
  • Moisture
  • Combine adjustments
  • Desiccant products
Physiological maturity can be identified when heads turn yellow. Photo coutesty of the National Sunflower Association.

Action Plan

  1. Determine stage of maturity. Sunflowers will reach maximum kernel fill and oil percentage at physiological maturity. This occurs 30 to 45 days after bloom. Visual evidence of physiological maturity includes heads turning from green to yellow and bracts turning brown. Seed moisture will be between 30 percent and 40 percent at maturity.
  2. Know when to harvest. Sunflower harvest can begin at 15 percent moisture, but the crop should be dried to 9 percent for proper storage. Sunflowers harvested between 9 percent and 14 percent moisture are easier to thresh and dry. Harvesting at less than 9 percent moisture can increase shellout.
  3. Prepare equipment. Wheat, row-crop and corn headers all can be successfully used to harvest sunflowers. Row-crop heads can be used without adjustment. Modify corn heads with a cutting knife before using with sunflowers. Various header attachments can be used to modify small grain heads.
  4. Decide when to use desiccants. Desiccants should be applied after the crop has reached physiological maturity to ensure maximum seed fill and oil percentage. Flowers desiccated at 35 percent moisture can be harvested up to 20 days earlier than nondesiccated flowers. Herbicides used for desication are more effective in warm temperatures.

Summary

Visual cues and moisture indicators are clues to sunflower maturity, helping determine harvest timing and whether to desiccate. Consult your Mycogen Seeds representative or trusted agronomic adviser for more information.

Published on Wednesday, September 10, 2014