Corn Grain Yield Estimator with Moisture Correction

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Equation / Last modified by KurtHeckman on 2017/04/10 16:24
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KurtHeckman.Corn Grain Yield Estimator with Moisture Correction

The Corn Yield formula estimates the amount of corn (maise) produced based on the size of the area planted and a sample of corn.  The result is the approximate number of bushels of corn (yield) for the field.

INSTRUCTIONS: Enter the following information from your 1000th acre sample:

  • (E) The number of ears of corn in your 1000th acre sample.
  • (KPE) The average number of kernels per ear in your sample 
  • (S) The size of kernels (see Kernel Size Guide below)
  • (CMC) The corn moisture correction factor (see Corn Moisture Correction below)
  • (A) The number of acres of corn

Estimated Corn Yield: This calculator will return an estimate of the bushels of dried (15.5%) corn that your land may yield.  This function is part of the Corn Yield Estimation Calculator.

Note: the rounded ends of the head are not considered since the combine will often not collect those kernels.

Sample Size

This calculator uses a standard sample size for corn yield, the 1,000th of an acre.  This makes the math easy and is a reasonable amount to measure.  To compute the length of a thousandth (1/1000th) acre row,  

  1. Measure the distance between your rows of corn and CLICK HERE.  This will tell you how far down the row will constitute 1/1,000th of an acre.  
  2. Then walk that length of the row counting the heads of corn and pick a reasonable sample of the ears, at least three that look pretty average to you. 
  3. Then shuck the corn and count the number of kernels of corn and compute the average (CLICK HERE).

You now have your sample, and there are only few more steps.
KernelSizes.png  Kernel Sizes Guide - Ruler is in inches.  

Kernel Size Guide

This formula uses the default of average sized kernels of corn in a bushel.  The ratios are as follows:

  • small - small kernels require 120,000 kernels in a bushel
  • medium - medium (average) sized kernels require 90,000 kernels in a bushel.
  • large - large kernels only require 80,000 kernels for a bushel. 

Corn Moisture Correction

This formula uses a Corn Moisture Correction. This takes into account that corn will shrink in volume as it dries.  A default of .89 is provided.  This is the approximate correction for corn that is harvested at 25% moisture and dried to the commercial level of 15.5% moisture. 

Corn is fully mature at about 35% moisture.  However, most farmers will allow drying to occur in the field to at least 28%, perhaps as low as 20%.  If you do not test your moisture level, you're answer will be off, but the default of 0.89 is a good start under normal conditions.


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