The Forgotten Elements Series, Part 6: Manganese
The Catalyst of Photosynthesis and Enzyme Activation
Manganese doesn’t get talked about much, yet it sits at the center of plant energy. It is the element that allows plants to split water molecules, release oxygen, and begin the photosynthetic process that drives all growth. Without manganese, photosynthesis simply cannot start.
What Manganese Actually Does
Manganese is needed by more than thirty enzymes tied to energy production, growth, and stress response. Its most important role is in photosystem II, where plants pull electrons from water and launch the first step of photosynthesis.
- Photosynthesis catalyst. Allows plants to split water and release oxygen.
- Enzyme activation. Supports carbohydrate use, nitrate reduction, and hormone balance.
- Chlorophyll maintenance. Helps keep leaves green and delays yellowing.
- Oxidative defense. Forms part of Mn-SOD, a key antioxidant system.
- Lignin and structure. Helps build stronger stalks and improves natural disease resistance.
Recognizing Manganese Deficiency
Manganese deficiency often looks similar to iron stress, but the yellowing is softer and more blended. Instead of sharp green veins on yellow leaf tissue, the color fades more evenly.
- Interveinal chlorosis on young leaves
- Gray speckling in oats or small grains (Gray Speck Disease)
- Reduced tillering and delayed maturity in cereals
- Weak roots and higher disease pressure
- Slower recovery after heat or drought
Deficiency usually appears in patches on ridge tops, sandy knolls, or freshly limed areas where manganese becomes tied up.
Where It Comes From and Why It Is Often Limited
Manganese is common in most soils but becomes unavailable when it oxidizes. Plants take up manganese as Mn²⁺, which forms under lower-oxygen, microbially active conditions. Dry soils, high pH, and heavy aeration push manganese into forms plants can’t access.
- High pH. Above ~6.5, manganese shifts into unavailable forms.
- Dry or compacted soils. Slow the microbial processes that release Mn²⁺.
- High organic matter. Can bind manganese and limit plant uptake.
- Excess iron or calcium. Compete with manganese at the root surface.
- Cold soils. Slow the redox reactions that free manganese.
Bringing Manganese Into the Program
Manganese is most important early in the season when photosynthesis is building. Keeping it available requires timely foliar support, balanced soil fertility, and strong microbial activity to keep manganese in its plant-available Mn²⁺ form.
- Foliar sprays. Apply light, timely applications during vegetative growth to correct early-season shortages and support energy production.
- Seed treatments. Adding small amounts of manganese to a biological or nutritional seed treatment helps support early energy formation and root development.
- Sap analysis. Use sap testing to monitor manganese mobility and catch shortages long before they become visible.
- Avoid phosphate mixing. Manganese binds with phosphorus; apply separately or use chelated forms to maintain availability.
- Biological cycling. Promote microbial activity that reduces oxidized manganese back into plant-available Mn²⁺.
At AgriBio Systems, we use Mn 8%, a plant-available manganese solution for both foliar and in-furrow use. It delivers consistent uptake during the stages when photosynthesis and energy production are ramping up.
Nutrients That Work With Manganese
- Iron. Partners with manganese in energy and redox processes.
- Zinc. Supports hormone balance influenced by manganese-dependent enzymes.
- Magnesium. Works with manganese in chlorophyll and energy transfer.
- Sulfur. Supports enzyme structure and helps manganese function better.
- Calcium. Works with manganese in lignin formation and membrane strength.
In the Field
Manganese deficiency commonly shows up first in dry, sandy, or freshly limed areas. Foliar correction usually improves color within a few days. Long-term improvement depends on managing soil pH and keeping microbial activity strong.
When manganese is available, crops use light more efficiently, stand stronger, and recover faster after stress. It plays a quiet but essential role in season-long consistency.
The Takeaway
Manganese is the often-overlooked spark that starts photosynthesis. It drives plant energy, strengthens structure, and supports natural stress tolerance. When manganese is lacking, the entire system slows. When it’s balanced, everything works better.
As we wrap up this post on manganese, we’d love to continue the conversation in person.
Come see us next week at The Big Soil Health Event — December 8–9, 2025 in Cedar Falls, IA.
Molybdenum — The Spark Plug of Nitrogen Fixation and Nitrate Reduction.
Explore the rest of the series on the AgriBio Systems Blog