You may have noticed that chelated micronutrients are used widely in our products. But what are they exactly and how do they work?
Chelate is a zooological term that means to have a “pincher-like claw” and is derived from the Greek word “khele” that means a claw or talon. It is used to explain the claw-like grip that chelates form with the inorganic nutrient.
In chemistry, the word chelate has come to mean combining a metal ion with a chemical compound to form a ring. However, in the technological realm of fertilizer, it represents a process whereby inorganic nutrients are wrapped in an organic molecule in order to make the inorganic micronutrients more bioavailable to a plant.
In the case of the chemical Ethylenedinitrilotetraacetic acid (EDTA), the EDTA surrounds the inorganic nutrient and gives it an organic coating. This organic coating around the micronutrient forms a weak bond with the nutrient and makes it more accessible to the plant – especially when it comes to foliar spraying of micronutrients on crops.
Chelates are most useful to surround micronutrients that are to be applied in alkaline soil conditions.
In the presence of alkaline soil conditions, micronutrients like zinc, manganese, iron, and copper all react with ions found at high pH to form insoluble substances. Unfortunately this ties up the inorganic nutrients and makes them unavailable to the plants growing in those soil conditions.
However, in the chelate, the organic coating works to prevent these challenging reactions ensuring that the roots of the plant are able to take up the chelated nutrient. Chelated micronutrients are also protected against precipitation and oxidation.
Once absorbed within the plant, the chelated nutrient releases itself and becomes available to the plant.
Chelated micronutrients are especially well-suited to foliar spraying.
Because inorganic nutrients cannot easily penetrate through the waxy surface of plant leaves, which is meant to trap in moisture and keep the leaves from drying out. These waxy surfaces also prevent inorganic substances from penetrating the leaf’s surface.
However, chelated nutrients are able to overcome this barrier, and are a logical alternative that work to help the nutrient penetrate into the leaf and release the nutrient into the plant to help promote growth at each stage of the lifecycle. One inside the leaf, the chelate then releases the micronutrient from the organic coating – making it available to the plant to use for growth and development.
Only a few nutrients are known to be able to be chelated - other nutrients cannot. These possible inorganic nutrients include, copper, calcium, iron, zinc, manganese, molybdenum and magnesium.
Additionally, there are several known organic substances commonly used as chelating agents that are generally used to produce most chelated micronutrients.
The most common chelating agent, synthetic EDTA, is utilized in a variety of soil and foliar nutrient applications.
There are also a number of natural products used as chelating agents.
Lignosulfonates, phenols, and polyflavinoids
These chelates are commonly produced by utilizing fermented wood-pulp industry by-products.
Citric acid and other naturally occurring organic acids like gluconic acid and malonic acid can also be used as natural chelates.