All crops require manganese for proper growth and development, so proper management of this micronutrient is vital for photosynthesis, germination and plant maturity, experts say.

“One action manganese contributes to in photosynthesis is the splitting of the water molecule,” says Joe Nester, agronomist and owner of Nester Ag in Bryan, Ohio. “A manganese deficiency can actually result in drought-like symptoms and poor use of soil water.”

How It Behaves

Manganese is present in many forms in soil, but plants can only use the divalent cation form, Mn2+. Plant availability is impacted by soil pH, soil aeration, weather, soil organic matter and the presence of other nutrients.

It is a soluble nutrient and is most available to the plant at a pH of 5 to 7. In alkaline soils with a pH higher than 7, manganese can become tied up in insoluble compounds, leading to manganese deficiency.

In acidic soils with a pH less than 5.5, manganese becomes more available and this may result in toxicity. Liming soils to achieve the proper pH is an appropriate management technique.

“Manganese can become less available to the plant in both water-logged conditions and very dry conditions,” Nester says. “These conditions change the form of manganese so it cannot be used by the plant. It is also easily tied up in organic matter, and with the muck soils we work with in Ohio we’re on a regular foliar program with manganese.”

Waterlogged soils facilitate more Mn2+ in the soil, while very dry soils have…