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Early Maturity Corn Hybrids and When to Switch

Categories: PLANTING, CORN
  • On average, hybrids will only lose 1 bushel for every 10 days of planting delay prior to May 10.
  • Planting dates after May 10 can experience up to 1 bushel of yield loss each day delayed.
  • Yield benefits of full-season hybrids offset potential grain drying cost enough to discourage switching Relative Maturity (RM) prior to the last week of May.
  • Corn hybrids mature with fewer accumulated heat units when planting is delayed, minimizing the risk of fall frost injury.
Golden Harvest Agronomy in Action research and numerous university trials have shown minimal yield loss (0.11 bu/day) from delayed planting up until May 10. After May 10, there’s a much bigger penalty (1 bu/day) for delayed planting. The thought of switching to an earlier maturity hybrid when facing a planting delay happens more frequently than most farmers would like. Thoughts of an early fall frost make the decision even more emotional. Before making big shifts to an earlier maturity hybrid, it’s important to understand what we’ve learned from previous research to make the most profitable decision. Here are a few key considerations regarding delayed planting.

A slight planting delay doesn’t necessarily require a switch to a shorter RM hybrid. Corn hybrids mature with fewer accumulated heat units when planting is delayed. This allows the same RM hybrid to reach physiological maturity in fewer days than earlier planting dates, reducing the risk of delayed maturity and potential frost injury. There may be a need to switch to an earlier RM hybrid at some point in time, but it’s important to remember that a day delay in planting doesn’t always mean a day delay in harvest.

Golden Harvest Agronomy in Action research has conducted multi-year studies to better understand the financial impact associated with switching to an earlier RM hybrid too quickly. Assumptions of $3.50 per bushel and $0.06 per point drying costs along with yield data from planting date trials were used to calculate $/ac return for full- (green line), mid- (yellow line) and short- (blue line) season hybrids. Full-season hybrids were defined as a RM ranging from the fullest acceptable for an area to minus 3 RM.  Mid-season hybrids were 4-7 RM earlier than the full-season hybrids. Short-season hybrids were 8-11 RM earlier than full-season hybrids. 

In over 41 trials, the yield benefits of planting a full-season hybrid outweighed the drying costs for higher moisture grain at harvest for planting dates up to the end of May. Considering moving 4-7 RM earlier at June 1 could be warranted. Aggressive RM changes of 8 or more RM may result in drier grain. However, yield potential of earlier RM hybrids will result in lower profit than drying a fuller-season hybrid. University recommendations for most Midwestern corn-producing states such as Michigan State University, University of Minnesota, Iowa State University and University of Wisconsin support waiting until May 20 to May 30 before switching to earlier RM hybrids.

There are, however, many reasons for switching to an earlier RM hybrid to consider. Lack of access to grain drying capabilities (bu/hr), grain contract delivery dates and harvest capacity (ac/day) are just a few reasons to consider switching earlier. If these factors aren’t a concern, you may have an opportunity to maximize your profit potential by sticking to your original hybrid selection. 

For more agronomic insights or for assistance on making this decision, contact your local Golden Harvest Seed Advisor.

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