How does a Growing Degree Unit and emergence impact yield?

What is a Growing Degree Unit and how can it impact your yield? That is our topic for today. Harvest is just around the corner and we can now see the results of early season activity in the field.

Oftentimes we evaluate emergence by the number of plants that successfully break through the soil rather than when the plants emerge. Although the number of plants which emerge is important, the timing of emergence is a notable factor in final yield potential.

This is why emergence timing matters. Take a look at the images below. Three plants from the same row emerged at different times. Yield is improved when plants emerge within 10 GDUs of eachother. When we see larger gaps in GDUs that is often when we see a noticeable difference in ear and stalk size.

A GDU is a Growing Degree Unit. Here is how to calculate a Growing Degree Unit (GDU):

GDU = ((Daily Maximum Air Temperature + Daily Minimum Temperature) / 2) – 50

We often see differences similar to those represented in the emergence trial below when corn is planted in soil temperatures under 54 degrees and when weather after planting becomes cold or rainy.

To create a more uniform emergence, here is what we recommend:

  1. Plant when soil temperatures are above 54 degrees with a 7-10 day forecast that has temperatures which will maintain the soil temperature.
  2. Make sure you are achieving a consistent planting depth and seed spacing.
  3. Encourage early germination by using a seed treatment and an infurrow row starter such as Triton.

To put together a crop plan for the 2018 growing season optimized for more even emergence, please contact me.


Growing Degree Unit

For more information:

We encourage emergence testing after planting. Find out how to conduct an emergence test here.

Several of our growers have achieved uniform emergence. Follow this link to see how one Ohio grower achieved 100% emergence.

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