Understanding Micronutrients: Zinc

 The seven essential micronutrients – zinc (Zn), boron (B), chlorine (Cl), copper (Cu), iron (Fe), manganese (Mn) and molybdenum (Mo) – are vital for plant growth, activating various processes within the plant, even though they are taken up in small amounts. While their requirements are smaller in comparison to macronutrients, they can still be the difference-maker in a crop’s overall success. 

What does zinc do in the plant? 

Zinc is a micronutrient essential for crop health and success. Zinc is vital from start to finish in the growth and reproductive cycle, as it is an integral part of many enzymatic processes that drive plant metabolism. Zinc is important for early development and growth, as well as in many other plant processes, including protein and chlorophyll formation. Zinc also supports the primary nutrients NPK. In short, high yields can only be reached with a sufficient amount of zinc. 

What conditions can lead to zinc deficiency? 

High pH soils are a typical driver of zinc deficiency — as pH increases, zinc availability decreases. Cold, wet soils can also impact zinc availability, and zinc solubility decreases in lower temperatures. Sandy soils often don’t have the clay and organic matter that helps hang on to nutrients, so zinc deficiency can also appear here.  

Soils high in phosphorus are a common culprit when zinc is deficient. Phosphorus and zinc can have an antagonistic relationship — meaning high levels of one can negatively impact the other. This is why proper balance in a fertility plan is so important. It is vital to remember that the crop uses significantly more phosphorus than zinc each year, so it takes less time to overcome an abundance of phosphorus than it will to correct an overapplication of zinc.  

What does zinc deficiency look like? 

In corn, a zinc deficiency can look like a phosphorus deficiency because there will be stunted growth, shortened nodes and limited root development. Zinc-deficient plants can have a white to pale yellow hue, often appearing in the growth closest to the stalk. It can occur as a non-uniform intraveinal chlorosis or a white midrib. 

In soybeans, plants with zinc deficiency display stunted stems in young plants with interveinal chlorosis on upper leaves that can appear as striping or banding. These plants may also have leaves with yellow tips, bronzing and early dropping of leaves. 

How can you address micronutrient concerns around zinc?

Soil and tissue testing are the primary methods for assessing zinc needs in your fields. If found early, a starter fertilizer or seed applied treatment with zinc can be the most economical approach, providing zinc when needed in the area where it is needed, supporting the 4Rs of Nutrient Stewardship — applying the right fertilizer source at the right rate, time and place. 

If tissue sampling shows a zinc deficiency, using a zinc sulfate, zinc oxide or a chelated zinc product will help address these concerns. One of the more efficient options includes WOLF TRAX Zinc DDP. 

Early access to essential nutrients is critical to ensure a successful crop, especially when it comes to zinc. With the ​WOLF TRAX™ DDP™ line of innovative nutrients — including Zinc DDP — crops can access what they need when they need it. WOLF TRAX supports early uptake of nutrients as it can maximize interception points and roots for early season uptake. 

To learn more about zinc and how to prevent zinc deficiencies, contact a Koch Agronomic Services (KAS) representative today or visit the KAS Knowledge Center for additional resources.