Gerald Almy: Important micronutrients for food plots, crops

Gerald Almy

Last week we looked at some of the reasons why micronutrients and a few other lesser-known elements are important for food plots and agricultural crops as well. Here’s a rundown on eight of the most important ones that plots might need.


Boron is vital for both forming and strengthening cell walls in plants and the formation of pollen. Roots absorb it as boric acid. It also assists plants’ uptake of potassium and phosphorous. It’s essential for helping calcium transport nutrients into and out of plant cells.

Boron encourages protein synthesis and seed development and helps many beneficial microorganisms in the soil thrive. If these weren’t enough benefits, boron also helps regulate flowering and cell division, pollen germination, and nitrogen absorption.

Plants vary widely in how much boron they need, but according to “http://www.cropnutrition.com”>Cropnutrition.com, “boron deficiencies are widespread across North America. From a global perspective, boron is the most widespread micronutrient deficiency after zinc.” Boron deficiencies can result in cracked stems, poor growth, and poor phosphate and potash absorption. Radishes may have dark spots and crack in the middle. Alfalfa and clover leaves turn yellow.


Plants, animals and man could not exist without calcium. It activates several important plant enzyme systems and helps form compounds that are part of cell walls, strengthening the plant. It improves root growth by encouraging microbial activity in the soil and enhancing the plant’s uptake of other micronutrients. It also stimulates leaf growth, aids in nitrogen fixation, and helps control a number of fungal and bacterial diseases.

Acidic or sandy soils are most likely to show calcium deficiencies. High concentrations of phosphorous can also bind calcium in the soil and make in unavailable to plants. Crops can show stunted growth and dying margins or curling of young leaves. Older leaves are rarely affected. Adding lime to bring the pH up to 6.5 will often solve deficiencies of available calcium.


Copper is vital for elasticity in plant stems, root health, and carbohydrate metabolism. It helps form proteins and amino acids, prevents wilting, and promotes cell wall strength. Copper is necessary for chlorophyll formation and enables the production of vitamin A.

It also assists beneficial microbes and controls fungus. It interacts positively with manganese and iron, stimulates growth, and prevents stunting and dieback.

Copper deficiencies can be seen in yellowing or olive-colored leaves, withering, and dieback of stems. Leaves may curl or fail to unroll on some of the plant. Young plants are especially vulnerable.


Next to aluminum, iron is the Earth’s most plentiful metal, forming around 5 percent of the planet’s crust. Because of that abundance, a shortage of iron for plants is not a common problem in food plots, but it can occur.

Iron absorbs heat and energy from the sun and transfers it to the plant, making the leaf darker green. It’s vital as a catalyst for forming and maintaining chlorophyll and increases the thickness of leaves for greater tonnage of forage.

Iron can be harmful if there is too little or too much. It’s affected by pH and becomes less available with readings above 7.0. Soils too high in phosphorous can also cause iron to bind with the phosphate, making both unavailable to plants.

Iron deficiency results in pale green leaves and a striped appearance from darker green veins. Often correcting the pH balance will help solve iron deficiency problems by unlocking iron that is in the soil but unavailable to plants. But additional iron may be required in some cases, either as granular ferrous sulfate (20-30 percent) or as a foliar spray.


Each chlorophyll molecule contains over 6 percent magnesium, making it a vital component for photosynthesis. It aids in plant respiration and phosphate metabolism, helping transport phosphorus to plants. It is vital for healthy root formation.

Since it’s involved in photosynthesis, plant leaves may lose their green color between veins when magnesium is deficient, giving a striped look. Older leaves are typically harmed first, especially on the lower part of the plant.


Manganese, closely related to iron, is important for several biological activities including photosynthesis, respiration, nitrogen absorption, and the creation of certain enzymes. It also helps in germination, root cell growth, and resisting root diseases. It helps plants achieve their full growth potential and enhances their ability to take up vital phosphorous and calcium.

Deficiencies can cause brownish-black specks spots and tan or yellow areas between the plant veins (interveinal chlorosis). Younger plants are often affected first, and stunting can also occur. If the pH is much higher than 6.5, manganese can become tied up in the soil and unavailable to the plant.


This element is often lacking in sufficient amounts in soils where food plots are grown, limiting their yield. Sulfur is vital for the formation of proteins and amino acids. It’s important for winter crop hardiness, and legumes such as soybeans and lablab require it for nitrogen fixation. Sulfur is what gives garlic and onions their pungent odors.

Sulfur deficiencies can lead to reduced growth of plants, smaller leaf size, and less branching. Plants can exhibit a pale green color throughout the leaf or occasionally a reddish brown hue.


Zinc helps make acetic acid in the root and helps prevent rotting. It’s an important part of many enzyme systems and is vital for getting maximum yield from crops. It increases corn ear size, promotes corn silking, and speeds growth. Like many other micronutrients, zinc becomes less available to the crop with high pH levels.

Deficiencies lead to stunted leaf growth and reduced hormone production. Diseases may occur in the plant that sufficient zinc would have prevented. High levels of phosphorous can also cause zinc deficiency in crops.