Minimize yield-limiting factors for a winning corn crop

INDIANAPOLIS — Purdue Extension corn specialist Bob Nielsen shared tips for achieving high corn yields at the Indiana Certified Crop Adviser Conference Dec. 17-18.

“It’s true that high-yielding corn requires a uniform, healthy crop canopy that can intercept and use about 95% of the incoming solar radiation by the time it hits flowering and throughout the rest of grain fill,” Nielsen said.

“This fact gives us something to aim for.”

Building the solar canopy begins with agronomic choices made prior to planting and continues through the end of the growing season.

“Unfortunately, our choices about these inputs change every year because Mother Nature changes every year,” Nielsen said. “So, it’s not easy, and we make different choices every year.

“It’s a continual process of making the right agronomic decisions in order to build that solar canopy that’s going to capture sunlight. The effects are going to be season-long.”

Nielsen offered three tips for a winning program:

• Improve your agronomic knowledge. Never stop the learning process.

• Identify, locate and diagnose important yield-limiting factors; do this as early and often in the growing season as you can. Crop diagnostics are most successful when you get out there early, when the evidence and signs are still there.

• Make sound agronomic decisions based on facts and data, not simply on logic.

The secret to achieving higher yields in the future, Nielsen said, is figuring out why you’re not achieving higher yields now.

“In other words, identifying and mitigating yield-limiting factors specific to individual fields,” he said.

“If you fail to identify and diagnose those yield limiting factors, then some of your agronomic decisions will miss the mark and you either waste money on inputs or leave yield on the table, or both.”

The search for yield-limiting factors requires agronomic knowledge and skills.

It takes time and is often difficult.

“Identifying yield-limiting factors is important because we should not be spending money on solutions for problems that we don’t have,” Nielsen said.

Successfully identifying yield-limiting factors involves walking fields, scouting for problems and taking extensive notes throughout the entire growing season.

Some yield-limiting factors to consider:

• Poor soil drainage.

• Hybrid performance.

• Soil compaction from tillage operations or repeated heavy equipment traffic.

• Weeds resistant to herbicides.

• Foliar diseases.

• Spatially variable nutrient deficiencies or excessively low soil pH.

• Secondary or micronutrients.

Yield maps can be road maps to problem areas in a field. Aerial images can also point to problem areas.

Nielsen also encouraged farmers to improve soil drainage where needed and feasible.

Improved soil drainage reduces the risk of ponding and saturated soils, soil nitrate loss due to denitrification, soil compaction and cloddy seedbeds from tillage of wet soils.

In a nutshell, good drainage enables successful root development and stand establishment of the crop.

Farmers also should put a lot of thought into picking their hybrids.

“Do not underestimate the importance of this seemingly simple decision,” Nielsen said. “Thoughtful hybrid selection can easily add 20 to 30 bushels per acre to your bottom line.

“Pay attention to hybrid characteristics that relate to stress tolerance. Look for hybrids that consistently yield well across a wide variety of growing conditions.”

At the end of the day, farmers and agronomists should remember to focus on the basics.

“We all need to sharpen our focus on the agronomic fundamentals of growing corn,” Nielsen said. “There are no silver bullets or one-size-fits-all solutions to improving corn yields.

“Use technology to supplement your agronomic decision-making, not replace it.”

Visit Nielsen's website at www.agry.purdue.edu/ext/corn/cafe/index.html.