Estimating Corn Yield before Harvest
Predicting a corn yield before harvest is becoming more popular with growers, but these estimates can be misleading. It is important to be careful when calculating estimated yields. You must determine the number of ears in 1/1,000 of an acre, average kernels per ear, average kernel rows per ear, and average value for seed weight based on the current year’s growing conditions.
Counting Harvestable Ears
Yield estimate accuracy increases with more sites tested. Yield estimates should be determined from at least five—and preferably ten—sites within a field. Field data collection is based on a 1/1,000-acre area. Table 1 gives row length needed to equal a 1/1,000-acre area for various corn row widths.
Yield Estimate Equation
Step 1. Count the number of harvestable ears in the length of row equivalent to 1/1,000 of an acre. For 30-inch rows, this will equal 17 feet 5 inches.
Step 2. Count the number of kernel rows and kernels per row on every fifth ear, and determine an average for each yield component. Do not count small kernels that might be located on the butt or ear tip. If variability in crop development exists within a given field, increase the sample size for better yield estimates.
Step 3. To determine the yield, transfer the values from steps 1 and 2, rounded to the nearest number, to Table 2, 3, or 4 depending on the current year’s crop growing conditions.
30 ears in 1/1,000 of an acre
14 kernel rows per ear
30 kernels per row
In a good irrigated corn field with no stress from pollination to physiological maturity, use Table 2 to find the yield estimate is equal to 164 bushels/acre. However, if your growing conditions were evaluated as extreme stress/dryland corn from time of pollination to physiological maturity, use Table 4 to find the yield estimate is equal to 113 bushels/acre.
Copyright 2014 by Mississippi State University. All rights reserved. This publication may be copied and distributed without alteration for nonprofit educational purposes provided that credit is given to the Mississippi State University Extension Service.
By Dennis Reginelli, Regional Extension Specialist for Agronomic Crops, North Mississippi Research and Extension Center.
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Extension Service of Mississippi State University, cooperating with U.S. Department of Agriculture. Published in furtherance of Acts of Congress, May 8 and June 30, 1914. GARY B. JACKSON, Director
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