06 Jun 2024
A tractor spraying a field

Manage Micronutrients for Higher Corn Yields

While macronutrients like nitrogen, phosphorus and potassium often take the spotlight, LG Seeds Agronomist Shane Irlbeck reminds farmers not to overlook the essential role of 
micronutrients for optimal corn yields. 

“With the longer emergence period due to cooler and wet conditions, it’s likely we’ll see more deficiencies showing up in the coming weeks,” Irlbeck says. “While we can’t control nature, we can take steps to help ensure crops have the best possible start.”

Key points

  • Micronutrients are crucial for corn plant development and productivity.
  • Soil testing and plant tissue analysis help identify micronutrient deficiencies.
  • Managing soil pH and drainage optimizes micronutrient availability and corn yield.

Required in much smaller quantities, micronutrients are involved in nearly every critical process during the corn growing season. These include iron, manganese, zinc, copper, boron, molybdenum and chlorine. Each plays a vital role in corn plant development, disease resistance and overall productivity.

Given their importance, it’s essential to manage micronutrient levels effectively. Irlbeck shares his management recommendations, including consideration of soil pH, moisture and inputs.

Spotting micronutrient deficiencies

Deficiency symptoms appear on the newest leaves or plant tissues first, as the plant transitions from relying on the seed for energy and establishing roots. “The most common deficiencies we’re seeing now are zinc, manganese and boron,” says Irlbeck.

Zinc plays a key role in cell elongation and division. A clear sign of zinc deficiency is pale yellow striping on leaves and stunted growth.

Manganese is crucial for photosynthesis and helps in forming chlorophyll. With manganese deficiency, look for interveinal chlorosis, or yellowing of the leaves, and weak stands. 

Boron is essential for reproductive development. It plays a bigger role in pollination and flowering, enabling silks to get pollen from tassels to kernels.

The detection of a micronutrient deficiency in corn can be difficult. Both soil testing and plant tissue analysis are often necessary to diagnose a micronutrient deficiency.

Corn plants lacking nutrients

Irlbeck says farmers should consider tissue testing for a more accurate view of what’s going on in fields. “There may be a case where the field has plenty of nutrients, but they’re not in the plants yet. More information helps us identify what the cause of the issue is — whether that’s an uptake issue or deficiency.”

Evaluating soil health and drainage

Soil health and pH are key factors affecting the uptake and availability of micronutrients to plants. “Make sure your soil pH is ideal for nutrient availability — in the 6.5 to 6.8 range for corn.”

Regular soil tests can help identify micronutrient deficiencies before they become a problem, and they also allow for targeted fertilization strategies. “If pH is lower or on the more acidic side, corn is more susceptible to micronutrient deficiencies. Adding lime can help get pH where it needs to be.”

In his area of central and southern Minnesota, Irlbeck tends to see more high pH soils. “In a lot of our areas, there’s excess salts from lack of drainage. If soil pH is more alkaline, 7.5 to 8, consider how tile might help flush those salts through the soil profile and get pH back down.”

Another big part of soil health and nutrient cycling is making sure there’s plenty of oxygen in the soil. “With this year’s wet, cool spring, drainage issues are a big challenge.”

In many fields throughout the Midwest, ponding creates a dry crust in the top half inch of soil while underneath stays wet. “Lack of oxygen causes poor emergence, so put tile in the right areas of the field where oxygen is lacking.”

Plan for success

Keep a close eye on soil’s micronutrient levels and consider them an integral part of a crop nutrition strategy. In some cases, Irlbeck says a foliar rescue treatment can be an effective way to address deficiencies quickly, especially during critical growth stages.

Farmers should balance their management plan to get the full potential out of corn plants. “Look at your soil test before the year, compare it to tissue samples and find where micronutrient balance is needed.” 

Ensuring plants have the right balance of micronutrients throughout the growing season helps optimize corn vigor, stress resistance and yield. Reach out to your local LG Seeds agronomist for help in evaluating field conditions and management decisions.