While copper is present in most U.S. soils, it is often tied up and unavailable to plants. It’s an essential micronutrient involved in many cellular reactions in plant cells. But at high levels, copper can be detrimental to plant development.

How It Behaves

Copper occurs naturally in almost all soils. It is a positively charged cation that binds to other nutrients and minerals in the soil, including clay, organic matter or metals such as iron, aluminum and manganese. In fact, copper binds more tightly to organic matter than all other micronutrients.

In the soil, plant uptake occurs through contact with the roots.

“Copper is relatively immobile. Anything growers can do to make sure the root zone is prepared for the crop, keeping it healthy and porous, will enable the root to do its job and absorb available copper from the soil,” says Kevan Klingberg, outreach educator at University of Wisconsin Extension’s Discovery Farms Program.

He notes there is still some mystery around copper’s precise role in plants.

“Within the plant, copper serves as a behind-the-scenes motivator,” he says. “We know copper is involved in a lot of enzyme systems and acts as an activator, or catalyst, to facilitate reactions inside the cells — including photosynthesis.”

In corn, the deficiency is first expressed within the whorl, and young leaves may show some streaking similar to iron deficiency. Leaf tips may die and the stalk may be soft and limp.

Copper deficiency can lead to reduction in starch formation, nodulation and nitrogen…