As growers approach planting season an annual question emerges, what is the optimal seeding rate for corn? It depends on your hybrid and how you answer these two questions.
- Are you trying to maximize yield or return?
- What kind of yield environment is your field location in?
Tom Bechman of Indiana Prairie Farmer explores the answers to the first question above with his own set of three important corn planting season questions.
- What’s the optimum agronomic plant population for corn – maximize yield?
- What’s the optimum economic population – maximize financial return?
- Can they vary by hybrid?
His article notes
These questions were first posed a couple of years ago when Bob Nielsen was helping producers understand the difference between optimum agronomic seeding rate, which looks at yield, and optimum economic seeding rate, which looks at return. After a two-year study with the same two hybrids, it was clear that optimum agronomic and economic seeding rates aren’t always the same. Likewise, it’s clear that both can vary greatly from hybrid to hybrid.
[Findings are from] a report on that two-year study conducted at the Throckmorton Purdue University Agricultural Center near Romney, Ind. Farm Progress helped sponsor this trial. Seed was provided by Beck’s, Atlanta, Ind.
Highlighting a couple of the study’s top 10 findings.
3. Optimum economic populations compared to optimum agronomic population varied by hybrid.
6. A seeding rate sweet spot was determined from several trials. Based on 90 Purdue field-scale trials, maximum yield occurs at final populations between 28,000 and 35,000 plants per acre on better soils.
The other top 10 findings from the study can be found at indianaprairiefarmer.com.
In 2016 a joint Kansas State University and DuPont Pioneer research study explored a similar set of questions. This study concluded that the optimal corn seeding rates depend primarily on yield environment. The study summarized its conclusions based on the type of yield environment the seeds are planted in.
MANHATTAN, Kan. – One of the most important economic decisions corn producers make every year involves choosing the right seeding rate. The answer often varies from field to field, and among different hybrids. Seeding rate decisions not only affect upfront production costs but also the final yield, said Ignacio Ciampitti, assistant professor of agronomy at Kansas State University.
“Decisions on hybrid placement field-by-field and seeding rate go together,” said Paul Carter, senior agronomy sciences manager with DuPont Pioneer. “Corn hybrids stress tolerance has improved with time and matching improving hybrid genetics with appropriate seeding rates is key to capturing the full benefit of genetic gain.”
“When you start looking at population studies, it can be overwhelming. We wanted to see if we could find some general patterns that would help give producers some guidelines in selecting seeding rates,” Ciampitti said.
In a low yield environment, average yields were maximized at about 90 bushels per acre with a population of 25,000 plants per acre, then declined gradually in a more-or-less straight line as populations increased, Ciampitti said. This was true at all latitudes and across all hybrid maturities.
In a medium yield environment, average maximum yield near 140 bushels per acre was also achieved with a population of about 25,000 plants per acre. Yields did not decline dramatically with higher populations, but neither did they increase.
In a high yield environment, yields increased relatively sharply as populations increased from 18,000 to 30,000 plants per acre, then peaked at about 35,000 plants per acre at a maximum yield average near 180 bushels per acre. Beyond that population level, yields declined.
In very high yield environments, yield response to plant population were still increasing in a relatively straight line at populations above 35,000 per acre.
Based on these two studies the general conclusion is planting populations ranges for corn should be between 24,000 and 35,000 depending on hybrid and yield environment.
Image Courtesy Indiana Prairie Farmer
Eager to get the seed in the ground? Be sure to pick the best corn planting date for your fields.
Also be sure to consider these corn planting tips for high yield.