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How you can change corn ear size and appearance within 20 feetHow you can change corn ear size and appearance within 20 feet

Stress wheel demonstrates how ear size and pollination effectiveness changes at higher populations.

Tom Bechman 1

September 8, 2015

2 Min Read

Higher plant populations in corn are no doubt the way of the future. Too many people are demonstrating how adding more plants per acre produces more ears per acre. More ears per acre means more yield per acre in most cases.

Related: Rows of kernels crucial for high corn yields

However, the stress wheel at the DuPont Pioneer research facility near Windfall, Ind., exhibited at the location's grand reopening recently indicated that all hybrids aren't ready for high populations just yet.


It depends how you define high populations. In this demonstration, plant populations went as high as 54,000 plants per acre. The stress wheel was created by planting several Pioneer hybrids in a circle, starting at 16,000 plants per acre for each hybrid on the outside of the wheel, and increasing the population to 54,000 plants per acre on the inside of the wheel.

In general, ears got smaller as population increased. Before you write off high population, recognize that 54,000 plants per acre meant about 3.5 times as many ears as at 16,000 plants per acre. Most sources say one extra average size ear per acre is worth about 6 to 7 more bushels per acre.

You can do the math. While the size of ears was considerably larger at the outside of the wheel, there was a big yield gap to make up. If you consider there are 3.5 times as many ears at 6 bushels per acre, that's a lot of ground to make up by larger ear size.

Most agronomists say there is a limit to how big ears can be. That's why more people are looking to thicker populations as the way to reach higher yields.

Related: Corn fights harder than you think for top yields

The wheel consisting of different hybrids allowed visitors to determine differences in how various hybrids in Pioneer's line-up today reacted to change in population. Ear size got smaller in every case. The ears were shucked back on a couple rows of each hybrid. Some hybrids in the wheel showed more – tip kernel abortion at the higher populations than others. Hybrids showing less tip kernel abortion might be better choices for very high plant populations.

About the Author(s)

Tom Bechman 1

Editor, Indiana Prairie Farm

Tom Bechman is an important cog in the Farm Progress machinery. In addition to serving as editor of Indiana Prairie Farmer, Tom is nationally known for his coverage of Midwest agronomy, conservation, no-till farming, farm management, farm safety, high-tech farming and personal property tax relief. His byline appears monthly in many of the 18 state and regional farm magazines published by Farm Progress.

"I consider it my responsibility and opportunity as a farm magazine editor to supply useful information that will help today's farm families survive and thrive," the veteran editor says.

Tom graduated from Whiteland (Ind.) High School, earned his B.S. in animal science and agricultural education from Purdue University in 1975 and an M.S. in dairy nutrition two years later. He first joined the magazine as a field editor in 1981 after four years as a vocational agriculture teacher.

Tom enjoys interacting with farm families, university specialists and industry leaders, gathering and sifting through loads of information available in agriculture today. "Whenever I find a new idea or a new thought that could either improve someone's life or their income, I consider it a personal challenge to discover how to present it in the most useful form, " he says.

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