It’s Too Soon to Switch Hybrids or Crops

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Lyle Marcus, Corn Product Manager

Due to the cold, wet spring weather we’ve experienced across the Upper Midwest – with more rain in the short-term forecast – some farmers are talking about switching maturities or even making the switch from corn to soybeans.

Many corn growers are questioning whether longer season hybrids should be swapped for shorter season hybrids. The quick answer is “no.”

There are several good reasons why farmers should wait at least until mid-May before making any changes to their current crop plan:

  • We’re still within the window of opportunity for maximum yields. Although corn is not being planted as early as last year, it’s still “early.” There are literally weeks of optimal planting dates remaining. Hundreds of acres of corn can be planted in just one good day, so wait for suitable planting conditions. Studies from our Land Grant Universities show there is very little yield difference between hybrids planted April 20 and May 20. Corn planted between April 20 and May 5 resulted in 100 percent yield potential, however, 99 percent yield potential was achieved with a planting date up to May 20.
  • Hybrids adjust to delayed planting dates. Adapted full-season corn hybrids can compensate somewhat for later plantings. As planting is delayed, hybrids shorten the time between planting and silking. Research shows that development and final yield of these hybrids will not be largely affected unless frost occurs especially early in the fall. That’s why university field agronomists recommend waiting until May 25 before switching to an earlier-maturing corn hybrid.
  • In general, fuller season corn hybrids out-yield shorter season hybrids. Expected corn prices can significantly affect one’s decision to switch maturities or even crops. Consider the yield potential and the cost of production before making your final decision. With the current corn market at $7, it could be worth sticking with a fuller-season hybrid in hopes of increased yield.

Also keep in mind that growing degree units (GDU’s) accumulation has been slow in 2022. During periods of cool temperatures, it can take several days to achieve those GDU’s. We have seen little in the way of GDU accumulation across Latham Country this spring, so we really have not missed out on time for crop development. This means that we are still very close to 100% potential, and our delays in planting are not taking much away from our 2022 potential.

Corn germinates best when the soil temperature is close to 50 degrees Fahrenheit, and our soils in the north haven’t yet warmed this much. Approximately 120 GDUs are required for corn to emerge. Once a corn seed germinates, it can exist for about 14 days on the energy that is contained in the endosperm. Under ideal conditions, the seed will emerge and develop a root system in much less than 14 days. Most researchers agree that soybeans emerge best when the soil temp is 55° F or warmer. Avoid planting soybeans if the temperature is below 55 degrees and a cold rain/weather event is expected within 24 hours after planting.

Below are a few additional resources that support sticking with your crop plan for now:

There is no need to switch corn hybrids or soybean varieties at this point. Patience is the key word this planting season!

Check out other agronomy and industry tips on The Field Position.