Manganese Requirements in Western Canada

Manganese (Mn) is involved with chlorophyll synthesis, photosynthesis, oxygen evolution and the activation of enzymes, e.g. fat forming enzymes. As a structural constituent of ribosomes, it also plays a key role in protein synthesis, helping improve N-utilization in the plant.

Why should this be important to you?

Mn sufficiency allows plants to absorb energy for light so it can grow into the crop and yield targets you are pushing for. Crops grown is western Canada will require anywhere from 0.6 – 2.0 g of Mn/Bushel.


In the soil

Manganese is naturally plentiful in most soils, so, in theory, supplies should not be limiting. However, deficiencies are commonplace when soil conditions combine to create a transient shortage.

Care is needed in diagnosing manganese deficiencies as often zinc and nitrogen are also critically deficient in the same soil.

Manganese in Prairie soils is affected by soil pH, organic matter & the environment.

  • Low pH (<5.4) or waterlogged soils can have Mn toxicity.
  • As pH increases, Mn becomes less available (especially on calcareous soils) because Mn increasingly converts to insoluble (unavailable) forms of Mn, so less Mn is plant available.
  • High organic matter (peat & muck soils) are often low in Mn.
  • Under cold wet conditions, Mn becomes unavailable.
  • Under warm & dry soil conditions, less water means less Mn uptake.
  • High soil iron can also decrease the availability of Mn.


Deficiency symptoms

Manganese is immobile in the plant and so deficiencies will show up in the younger leaves. The first symptoms are a general paleness of the younger and mid leaves due to reduced photosynthesis rates and chlorophyll content. The areas between the leaf veins yellows and the leaves become limp and soft. When severe, these yellow areas die, leaving spots or streaks of dead tissue. Oats are the most sensitive cereal to manganese deficiency, followed by barley, wheat, triticale and then rye. Legumes, for example can also be sensitive to manganese deficiency.



Manganese toxicity affects plant development rather than root growth. Symptoms range from yellowing (chlorosis) of leaf margins to death of tissue. They appear on the older leaves first.



Effect on Seed Quality

Low manganese levels will reduce the oil content of seed and create deformed cotyledons in legumes (marsh spot in peas, split seed in lupins).

Toxic levels of manganese can inhibit and lower the levels of other nutrients such as calcium, magnesium and iron which result in poor produce quality due to these consequent deficiencies.


Fertilizer Placement and Timing

Manganese can be applied on the seed, with or on the fertilizer (YaraVita PROCOTE) or on the leaf with YaraVita GLYTREL MnP

Foliar sprays are commonly used for correction of deficiencies according to plant analysis or as soon as visual symptoms appear.

When fertigating in calcareous soils, apply Mn-chelates for best effect.


Pure Solution with Pure Results

YaraVita GLYTREL MnP increases soybean yields by stimulating root growth and supplying much needed energy during critical growth periods. It’s a liquid that has been specifically formulated to be sprayed at the same time as glyphosate.

  • Proven yield response
  • Reduces glyphosate stall
  • Boosts root growth
  • Mn is protected from glyphosate chelation
  • Mixes easily with most pesticides
  • Humectant properties allow better uptake
  • No need for additional surfactants
  • Built –in pH reduction


Nutrient Interactions

Oversupply of other divalent cations can limit manganese (Mn2+) uptake. For this reason it is quite common for manganese and zinc deficiencies to occur at the same time.
In addition there is often antagonism between iron and manganese uptake. High levels of iron can induce a manganese deficiency and vice versa.

Listen Now: Your Crop Requires More Than Just Macronutrients

Listen Now

In interview to Real Ag Radio on March 28, 2019, Yara's Crop Manager Markus Braaten talks about the critical role each micronutrient plays in producing the best possible crop.