Update from the Field: Small Quantities, Giant Rewards Part 3
Posted by Dave Dyson, Agronomist on February 18, 2019
This post may reference products and/or services only available to our Retail Farm Center customers. For more information contact your Territory Manager at The Andersons.
The third article in my four-part micronutrient series will focus on the micronutrient manganese (Mn). Great things come in small packages! Manganese may be needed in small quantities, but it activates several important metabolic reactions and plays a vital role in photosynthesis by aiding in chlorophyll synthesis. Manganese accelerates germination and maturity while increasing the availability of phosphorus and calcium. Manganese is very immobile in plants, so deficiency symptoms appear first on younger leaves, the top leaves of the plant. The symptoms can be described as interveinal chlorosis, yellowing and light green or white areas between the veins, while the veins stay green. Sometimes a series of necrotic brownish-black specks appear prior to leaf drop. Stunting and premature death will occur if a severe deficiency is not addressed and corrected.
While corn can show signs of manganese deficiency, soybeans and wheat, in particular, require more manganese than many other crops. There are three circumstances where we most likely will see manganese deficiency. The first situation is in a high pH soil. We usually do not see soils with pH higher than 8 east of the Mississippi River. This situation normally presents out West, and an application of sulfur will help reduce tie up and increase soil available manganese.
Figure 1: In this chart you can see that as the pH increases, the availability of Mn decreases.
The second circumstance is more location driven. Manganese can be easily tied up in organic matter and made unavailable to the plant. Crops planted in low lying, muck, or peat soils can routinely show manganese deficiency. Adding Mn to the soil will do little to correct these plants’ symptoms, since the additional manganese will be tied up in the organic matter as well. Post applying a high-quality Mn product like Eezy™Man at 2 qt/ac or 1gal/ac of OverPass™ SF Plus will push enough manganese into the plant that within three days the symptoms will all but evaporate.
The third and most common situation we see is a “yellow flash”, or temporary Mn deficiency immediately following an application of glyphosate. Glyphosate is toxic to susceptible plants, resulting in the death of the plant following application. Glyphosate-tolerant (GT) crops have the ability to digest glyphosate so as not to kill the plant. Glyphosate-induced Mn deficiency can compromise the plant’s natural resistance to diseases, according to Dr. Don Huber, Emeritus Professor, Botany and Plant Biology at Purdue University. Experiments have shown that a glyphosate application on GT soybeans reduces the efficiency of manganese uptake by 10 to 50 percent. Applying a maintenance rate of Mn with every glyphosate application will help eliminate the occurrence of “yellow flash”.
In conclusion, The Andersons has several great products to either reverse and rescue the crop from manganese deficiency or prevent the deficiency from happening. Contact me or your local Ag advisor at The Andersons if you need help determining when and what source would be best to apply manganese on your crop.
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Dave Dyson is a regional agronomist for The Andersons’ Farm Centers which are located throughout Ohio, Michigan, and Indiana. He is an Indiana native and grew up on a dairy farm in Miami County. A graduate of Purdue University with a degree in Crop & Soil Science, Dave has a deep knowledge of various agronomic topics and is committed to helping growers improve their crops. If you have any questions, Dave can be reached at david_dyson@andersonsinc.com.
Eezy and OverPass are trademarks of The Andersons, Inc.
