Importance of Micronutrients

Micronutrients are as vital to agriculture as vitamins are to the human diet.

As farmers, we know that crops need the right balance of Nitrogen, Phosphorus, Potassium and Sulfur to grow and achieve maximum yield. However, we often forget about the micronutrients needed by plants and the vital role they play in growing healthy, high yielding crops. Even though plants require smaller amounts of micronutrients, if plants are deficient in certain micronutrients it can have a huge impact on a crop’s health and yield.

Liebig’s Law of Minimum

For a plant to reach maximum yield potential, all the macro and micronutrients need to be available in sufficient quantities and in balance with each other. Even though the soil contains all the nutrients the plants need, often these nutrients are tied up in the soil and are unavailable to the plant. This is why the supplemental application of micronutrient foliar fertilizers is important to ensure the plant receives any nutrients that it may not be getting from the soil in sufficient quantities at all critical stages of the plants life cycle.

On the left is Liebig’s Law of Minimum. It refers to the fact that the crop grown in a particular soil will be limited in yield potential by the lowest board. That lowest board is a macro/micronutrient that is the limiting factor for the yield of that crop. If the board/deficient nutrient can be raised then the yield will improve.

The six crucial micronutrients

There are six crucial micronutrients. These are: Iron, Copper, Zinc, Manganese, Boron, and Molybdenum. Growing crops often need these micronutrients in quantities greater than what the soil supplies. Let's take a look at the roles all these vital micronutrients play.


  • This element is essential to life on our planet. Manganese is the element that facilitates reproduction for every living thing.
  • It works with iron as an enzyme growth activator and assistant.
  • This element puts the key in the ignition of the phospholipase enzyme system- providing chloroplasts so that photosynthesis, and growth, can occur.
  • As an element it is related closely to phosphorus.
  • It activates the distribution enzyme that controls the auxin-produced regulators.
  • Because it is so closely tied to reproduction, seeds won’t develop without it.
  • Manganese works closely with zinc. Zinc assists in the production and development of the hormone auxin, while manganese regulates distribution and supply.


  • An important plant enzyme activator.
  • Is known to play a role in the various plant complexes related to the formation of chlorophyll - the material in plants that gives them their green color and is vital for photosynthesis.
  • Serves an energy-changing role in amino acid production.
  • Is the activation key to the production of glutamic dehydrogenase – an enzyme that links ammonia and organic acid to produce glutamic acid. Additionally, the enzyme glutamic dehydrogenase is known to link amino acids and form them into finished proteins.
  • Turns nitrogen into a usable protein.


  • Activates Growth.
  • Another important micronutrient that works hand-in-hand with Manganese to produce the growth regulator auxin by activating the enzyme system.
  • Zinc, when applied as a foliar spray or added as a soil amendment, produces an immediate increase in auxin production in plants and corrects stunted growth.


  • Crucial to the development and production of chlorophyll.
  • Plays an integral role in gathering moving charged electrons and directly responsible for the production of respiration energy.
  • Controls regulator movement by activating the system of enzyme transport.
  • Needed to develop cytochrome – an iron activated enzyme which gathers electrons and mixes them with low energy phosphates to then create and discharge energy rich phosphates.


  • Creates starch.
  • Regulates carbohydrate metabolism.
  • Acts as an enzyme activator for the starch phosphorylase which plays an integral role in the movement of both carbohydrates and sugars in plants.
  • Maintains a sugar and starch balance in plants.
  • For some plants, creates the starch needed for root development.
  • Assists in the development of quality fruits and seeds.


  • Ensures that plants can utilize available nitrogen.
  • Is needed by plants to form amino acids from nitrate nitrogen.
  • Assists in the production of plant-based ammonia.
  • Controls plant sugar content.
  • Assists in metabolism of plants.
  • Produces the energy carrier liacin.
  • Is crucial to the nitrogen fixing nodule bacteria that form a symbiotic relationship on the roots of legumes.

Micronutrient content in our soil

Micronutrient content in our soil

Sandy soils, and soils low in organic matter, are usually also low in micronutrient content. However, we also know that crops grown in soils that are high in organic matter percentages (6% or more) often need more micronutrients than low organic soils.

Additionally, almost any natural condition or farm practice (including chemical fertilization and herbicide application) that slows root growth and development can also induce micronutrient deficiencies. Stay on top of your crop and watch out for deficiencies when any of the following conditions occur in the field:

Micronutrient content in our soil
  • High organic matter (6% or more) or low organic matter.
  • Sandy soils.
  • Drought.
  • Compaction.
  • A pH that is too high or too low.
  • When high levels of macronutrients are applied.

Click here to learn more about how soil affects plant health and growth.