Trace Elements: What Are The Effects Of Trace Minerals On Plant Growth

Every gardener knows that generous nitrogen feeding makes the lawn greener and plants healthier.

They know phosphorus-deficient plants are puny and weak.

Plants lacking potassium have mottled stunted foliage later develops tiny patches of dead tissue over the surface.

graphic of organic soil and trace elements

But what about when the garden has:

  • An ample feeding of nitrogen, phosphorus, and potassium
  • A soil in good condition
  • Favorable weather

… and still the plants are dwarfed or the foliage is distorted or the growing tips fail to elongate or the plant is discolored?

These are instances when trace elements analyses are needed.

A trace element, or trace mineral, or essential mineral (all terms for the same thing) is a chemical that has proven necessary for normal plant growth but is used by plants in extremely small amounts.

In fact, the history of trace elements does not go back to the turn of the century. This is because they occur in such tiny amounts that they were not detected until late in the development of soil science and plant nutrition studies.

Trace elements usually are not used structurally in plants – they play no part in the final structure of cell walls or in protoplasm.

But they are absolutely necessary in the production of cell walls and in the synthesis of protoplasm and in the vital activities of living cells.

Since they are not used up, a little bit goes a long way. But if that little bit is lacking, the whole operation that depends on it is in trouble.

It has become popular to refer to trace elements as organic catalysts and this is a good term though it requires some explaining to laymen.

A Catalyst

A catalyst is a substance that speeds up a chemical reaction without actually entering into the reaction.

Here is an example:

Substance A reacts with Substance B to form Substance X. This reaction is extremely slow.

But if we add a pinch of Substance C to the mixture of Substances A and B the reaction occurs more quickly, resulting in a rapid formation of Substance X, but, when the reaction is completed, the original amount of Substance C remains in an unchanged state.

The reaction of A plus B to form X was speeded up by C, but C did not get used up in the reaction. Therefore we say that Substance C catalyzed the reaction.

An organic catalyst is a substance that speeds up reactions in living cells and acts as a sort of a regulator for the many complex processes that sustain life in the protoplasm of a cell.

In many cases these organic catalysts are mineral elements.

Since just a small amount is needed in a plant, and that amount is used over and over again, early plant chemists referred to traces of manganese, boron, zinc, copper and other elements in their analyses of plant tissues.

Now we know that the minute portion of each of these trace elements is absolutely essential to the well being of the plant.

Magnesium

Magnesium is one of the more easily detected trace elements.

If it is lacking in the soil our plants are yellowish and dwarfed. Plant chemists tell us that magnesium is essential in the synthesis of chlorophyll in living plants.

Chlorophyll is the green pigment of plants which is involved in the synthesis of sugar in living plant cells.

If magnesium is lacking, no chlorophyll is formed and the plant is not green; since it cannot make sugar, it is dwarfed.

The easiest way to add magnesium to your soil is to apply epsom salts (magnesium sulfate) either as a solution in water or as a dry powder.

Manganese

Manganese is apparently involved in several processes including chlorophyll formation, cell respiration (breaking carbohydrates down into water and carbon-dioxide, using the energy thus released) and in the conversion of one sort of carbohydrate to another sort.

Manganese utilization is still very vague to us, but we know that plants cannot do without it.

Boron

Boron is another element that is found in the minutest quantities in plants. In fact, it has been proven essential to plants and animals in very recent years, but why it is essential we arc not sure.

Plant physiologists report that plants grown on boron-deficient soils fail to make healthy buds and root tips, and the plants develop abnormally. Boron is found in the recently discovered vitamin Bn.

Zinc

Zinc exerts its effect on plant growth in a second hand fashion. Apparently it is essential to the production of certain plant hormones and these, in turn, control certain phases of plant growth.

Citrus growers are especially sensitive to a proper zinc level in their soils.

For many years a “rosette” effect on orange trees was attributed to a virus. Later it was found that driving a zinc-coated nail or two into the tree corrected the situation.

Copper

Copper, like zinc and boron, is known to be essential in small amounts and in some cases, is toxic if over done. Copper is involved with certain enzymes that control respiration in living plant cells, and it is thought to be involved in other areas of plant physiology as well.

Sulfur

Sulfur is with the trace elements as a matter of tradition. Now we know that it is used structurally in many plant proteins and actually is found in surprisingly large amounts.

However, it plays also a role, at least in some plants, in chlorophyll synthesis and it is involved also in respiration.

This discovery of sulfur’s structural role points up a fallacy in the entire classification of trace elements.

Today it is known that sulfur is structural, found in some proteins, that magnesium is structural, found in the chlorophyll molecule, that calcium is structural, found in the cell walls of very young cells, and therefore these elements deserve a double classification: structural in one role, behaving like true trace elements in another.

Calcium and Iron

Calcium and iron were discussed in our article on Soil Fertility, but, to keep the list as complete as possible, let us include them once more, calcium as a controlling factor in the permeability of cell membranes and iron as an essential element to the formation of chlorophyll.

Just a word about using trace elements, and why we must use them.

As we cultivate our soils and the rains wash over them, trace elements are washed away – why else do you suppose the ocean is “salty?”

As we plant our crops, flowers, and lawn and harvest them or haul them off or burn them we lose the trace elements they contain. Our soils are becoming depleted.

There is another danger – that of adding too much of any one trace element and creating a toxic condition.

There are several good trace element mixtures on the market with Azomite (click for details) being one of the best.

These, used according to the manufacturer’s recommendation, will improve the health of your soil by improving the health of its microorganism population and will improve the health of your plants directly by supplying them with essential trace elements.

by John Baumgardt