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Corn yield forecasts and grain dry-down guidelines

By Jeff Coulter, Extension corn agronomist

End-of-season forecasts of corn grain yield were recently made by researchers from the University of Nebraska for several locations across the Corn Belt, including three in Minnesota. These forecasts suggest above-average yield for the Minnesota locations, but high variability in yield for rainfed corn across the Corn Belt. Averaged across locations, the predicted yield is near the long-term (2005-2019) average and 15% less than that in 2019.

Most corn in Minnesota has reached physiological maturity. When corn reaches physiological maturity, a black layer is present at the tip of kernels where they connect to the cob. The black layer can be observed by scratching off the tissue at the tip of kernels or cutting kernels lengthwise. Grain moisture content is about 32% when kernels first reach maturity. 

To help plan harvest, typical in-field dry-down rates for corn grain in Minnesota are listed below. These rates vary due to factors such as solar radiation, air temperature, wind speed, and relative humidity.
  • 0.75 to 1.0 percentage points per day during September 15 to 25
  • 0.5 to 0.75 percentage points per day during September 26 to October 5
  • 0.25 to 0.5 percentage points per day during October 6 to 15
  • 0 to 0.33 percentage points per day after October 15
For more educational resources on corn production, visit Extension's corn production website

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