Will Supplemental Growth Hormones Increase Quality or Yield?

Fertilization question asked by Travis in Ballard County 7 months ago.


In an intensively maintained operation, will the addition of the plant growth hormones IBA (auxin) and kinetin (cytokinin) in an existing foliar application be successful in increasing either yield or quality?

Should there be a concern with downward taproot growth when applying IBA to seeding year alfalfa?

Fertilization in Ballard County
posted 7 months ago
Travis H.
Ballard County

1 Answer Posted

This post is marked as an accepted answer for the question.

Plant growth hormones can increase plant growth in forages including alfalfa, but the results have been inconsistent in providing a consistent yield increase. In most cases,  limited spring growth in alfalfa is caused by poor growing conditions (including cool wet weather) or low fertility and low pH. Therefore, I would not encourage applying plant growth hormones. If hormones are applied it is important to first make sure that pH is 6.5-7.0 and that soil test nutrients are at a high level (phosphate >60  lbs/acre and potash >300 lbs/acre). In other words, fertilize first before spending money on plant growth hormones.   

answered 7 months ago
Ray Smith
Jessamine County
Official Public Agronomist (Extension Agent)

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