Could your Soybeans Yield More with Manganese and Iron Fertilizer?

By Wolf Trax

There are two micronutrient issues that farmers should consider when they are getting ready to apply their soybean fertilizer. The first is manganese deficiency in soybeans. It is a common deficiency in soybeans throughout the Midwest and mid-Atlantic states where fields have high soil pH, coarse soils, high calcium levels or high iron levels. Unfortunately it is often addressed after crop stress has started.

The second issue is iron chlorosis in soybeans. Northern soybean farmers know iron chlorosis too well when spring conditions have become cold and wet.

Don’t Wait for a Manganese Foliar Spray

I’ve seen in recent years the growing popularity of in-season foliar applications of manganese fertilizer for soybeans. Part of the reason why the foliar fertilizer practice has grown is the obvious visual response that many farmers see after an application. The soybean plants take on a greener color. That’s because manganese is important for photosynthesis.

But what if I told you that the visual response – that greener color after a foliar application – is a bad thing?

Seeing a difference in your field means the soybean plants did not have enough manganese before the foliar application. During the time you were robbing your soybean crop of this important micronutrient, you were also losing yield.

At Compass Minerals we advise our customers to deliver the nutrients before they are needed by the plant. You can do this by coating your dry soybean fertilizer with Wolf Trax Manganese DDP® or mixing Manganese DDP with your starter fertilizer.

Optimize Manganese Fertilizer Application Timing for Soybeans

Foliar fertilizers aren’t bad – as long as you make sure your soybeans have the manganese they need early.

At Purdue University, Dr. James Camberato conducted research on timing of manganese fertilizer applications in soybeans. For applications at planting, he added Wolf Trax Manganese DDP at a rate of 0.5 lb/acre to 10-34-0 starter fertilizer. And for in-season foliar applications, he added Manganese DDP at a rate of 3 oz/acre to glyphosate. The trial’s check received no starter fertilizer or manganese.

The trial’s key findings:

  1. Adding just a starter fertilizer with no manganese made almost no difference in yield, only half a bushel more.
  2. The best results came from a programmed approach: including Manganese DDP with a pre-plant/at-plant fertilizer application and again in a foliar spray.
  3. The next best option was NOT spraying just an in-season foliar application of manganese fertilizer. Instead, the second best option was applying Manganese DDP at planting.

For more details on this soybean fertilizer trial, download the Field Insights document.

Provide Manganese to the Whole Soybean Plant

Besides making sure that the plant has access to the nutrient when it’s needed, a soil application also ensures the whole plant benefits from the fertilizer application. Manganese is immobile in the plant. A foliar application supplies the important micronutrient to the part of the plant that is sprayed. Manganese will not redistribute itself to new growth.

When roots take up soil-applied Manganese DDP, however, the micronutrient is distributed throughout the whole plant.

Avoid Iron Chlorosis in Soybeans

If you live in  a northern soybean growing region that experiences iron chlorosis in soybeans, don’t let the weather induce iron deficiency in your crop. The results of iron deficiency chlorosis can be reduced photosynthesis and lost yield.

By using Wolf Trax Iron DDP with EvenCoat Technology, you can soil-apply a low-rate, blanket-like distribution of readily available iron that soybean plants can uptake early in the season.

Make sure you provide the soybean fertilizer requirements your crop needs for a great season.


About the Author Wolf Trax