|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.|
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.
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.
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.
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.
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.
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.
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.