Secondary Nutrients & Micronutrients in Crop Production

May 22, 2020
Megan Hasenour | Marketing Communications Manager


Secondary Nutrients & Micronutrients are essential nutrients required by the plant in smaller amounts than macronutrients. Although plants only require relatively small amounts of secondary nutrients & micronutrients, they are essential for plant growth. If they are deficient, critical plant functions can be limited resulting in plant abnormalities, reduced growth and lower yield potential.

Key secondary nutrients and micronutrients required for optimal crop production:
Secondary Nutrients: sulfur & magnesium
Micronutrients: zinc, manganese, boron, copper, iron, molybdenum, chloride & nickel.
Secondary Nutrients
Sulfur (S): Sulfur is an essential nutrient for plant growth and has various functions in plants. It is found in some amino acids and is essential for chlorophyll formation. It is active in the metabolism of nitrogen. Sulfur deficiencies are more likely in sandy soils with low organic matter and under high rainfall conditions. Sulfur deficiency first appears on younger leaves. 
Magnesium (Mg): The powerhouse behind photosynthesis in plants. Without magnesium, chlorophyll cannot capture sun energy needed for photosynthesis. Magnesium is required to give leaves their green color. Magnesium deficiency in plants is common where soil is not rich in organic matter. Heavy rainfall can cause a deficiency to occur by leaching magnesium out of sandy or acidic soil.
Zinc (Zn): This micro, which plays a role in conversion of starches to sugars and other metabolic processes, can sometimes be deficient in high-pH soils, and cool and wet soils. It is the most common micronutrient deficiency. Zinc aids in carbohydrate, protein and chlorophyll formation and is an important component of various enzymes responsible for driving metabolic processes. Deficient corn shows white striping bands on leaves. Potential soil and crop conditions for zinc deficiencies include high pH soils (greater than 7), cool wet soils and high phosphorus rates.
Manganese (Mn): Manganese activates enzymes in growth processes and is essential for chlorophyll development. A deficiency of this micronutrient can turn plants to an olive green with faint striping. Potential soil and crop conditions for a manganese deficiency includes black sands, mucks, poorly-drained depressional soils with less than 6.2 pH.
Boron (B): Boron aids in the structure of the cell wall. It can be easily lost to leaching in heavy rainfall. As soil pH increases, boron availability will decrease.
Copper (Cu): This micronutrient promotes seed production in plants and has a role in chlorophyll and enzyme activity. Copper is needed to activate several plant enzymes that are essential for building and converting amino acid to proteins. Copper deficiency symptoms occur most on new plant growth where the plant takes on a bleached appearance and may die. Potential soil and crop conditions for copper deficiencies include organic soils and black sands.
Iron (Fe): Iron is needed for the development of chlorophyll in plants. It is an activator for respiration, photosynthesis and nitrogen fixation. This micronutrient is a component of several enzymes. It assists in nitrate reduction and energy production and is essential for the formation of chlorophyll.
Molybdenum (Mo), chloride (Cl), nickel (Ni): These are the smallest micros of the micronutrients. Hardly ever are these deficient in area crops, but it’s best to always test for them. Molybdenum is an essential component of enzymes needed for nitrogen metabolism and the synthesis of amino acids in plants.
The secret with any micronutrient is knowing what crops may be sensitive to a deficiency and knowing which yield conditions may limit availability.

Don’t let something as small as a micronutrient deficiency minimize your yield. Feed your plants what their hungry for – FEED THE BEAST!

Contact your local Superior Ag agronomist to see what your plants might be missing.