By John Brien, CCA, regional agronomist for AgriGold
The Yield Component Method is one of the most versatile and utilized methods to estimate yields. It allows growers to estimate their corn yields as early as 25 days after it takes into consideration the key components that determine grain yield. Yield components include the number of harvestable ears per acre, number of kernel rows per ear, number of kernels per row and kernel weight. The first three components are easily measured in the field while the value for kernel weight for ease of computing is a predetermined factor.
When estimating yields with the Yield Component Method there are several key points to keep in mind. When rainfall during grain fill is below average, the yields will be overestimated, while good grain fill conditions will underestimate yield.
Below is an example of the Yield Component Method to estimate grain yield.
Step 1. Measure a length equal to 1/1000th of an acre. For 30-inch rows, this would equal 17.5 feet.
Step 2. Count the number of harvestable ears within the measured area.
Step 3. Count the number of rows of corn and the number of kernels per row on every fifth ear of corn in the measured area. Multiply the number of kernel rows by the number of kernels per row; this equates to the total number of kernels per ear.
Step 4. Calculate the average number of kernels per ear by adding the total number of kernels per ear and dividing by the number of tested ears.
Step 5. Calculate the estimated yield by multiplying the ear count per 1/1000th of an acre by the average number of kernels per ear then divide the result by 90.
Repeat the above procedure throughout the field as many times as needed to acquire a fair representation of the field. Keep in mind the Yield Component Method only provides an estimate. Since kernel size weight can vary between hybrids and environments, this method should only be used as an estimate. Other tips:
• For other row spacings, divide 43,560 by the row length in feet and then divide the result by 1000.
• Do not count the kernels on the extreme butt or tip of the ear.
• Yield = (# of ears/1/1000th acre) x (avg. row #) x (avg. kernel #) divided by 90
• The value of ’90’ represents the average number of kernels (90,000) in a bushel of corn. Use a lower value (80) if grain fill conditions have been excellent or a larger value (100) if grain fill conditions have been stressful.