December 2, 2019

When Should I Switch to an Earlier RM Hybrid?

The 2019 planting season was severely delayed across much of the Corn Belt. Most of the corn crop in Illinois was not planted until after June 3rd.
Farmers are asking for guidance around when they should consider switching to an earlier relative maturity (RM) hybrid to mitigate the risk of a killing frost before the corn crop could mature.
The Bayer Learning Center at Monmouth, IL conducted a trial to evaluate the difference in yield and return over drying cost among a range of RMs planted on two different dates in June.

Six different corn products ranging from 95- to 114-day RM were planted on two different dates in 2019:
- June 3rd
- June 11th
All plots were harvested on October 28th and adjusted to 15% moisture.
Yields were calculated and compared as was return over drying cost.

Yields were consistently higher in the June 3rd planting with the exception of the 108-day corn product (Figure 1).
- Even though this product yielded higher in the later planting, higher drying costs led to the earlier planting date being more profitable.
Moisture was substantially higher across all plots planted on June 11th (Figure 1).

Return over drying costs declined substantially from the June 3rd to June 11th planting date (Figure 2).
- However, returns for the later RM corn products were still higher than the two earliest RM corn products.

Corn products that were earlier in maturity than the typical RM range for the area (105- to 115-day RM) did not yield or return well compared to the corn products that fit the area in a ‘normal’ growing season.

These results suggest that while switching from late-maturing to earlier-maturing hybrids may be justified by the 2nd week in June, farmers should still consider staying with a RM that fits their geography.
Growing conditions are highly variable form year to year. Consult your local Technical Agronomist or Field Sales Representative for specific recommendations for your farm.

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