The difference between amino acid chelated trace elements and EDTA chelated micronutrients.
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What is a chelate?
Chelate is a type of complex. In the structure of a chelate, there must be one or more multi-dentate ligands that provide multiple pairs of electrons to form coordination bonds with the central body. “Chelate” refers to the crab’s large claws. This name is a metaphor for the multi-dentate ligands that use two large claws to tightly clamp the central body like a crab. Chelates are usually more stable than general complexes, and the five- or six-membered ring structure that often exists in their structure enhances stability. It is worth noting that some chelated chemicals are shaped like the letter “C” and only use one molecule to surround the mineral. This type of binding is called a “complex”. Only when two molecules of the same material surround a mineral is it called a chelate. Or some minerals, such as boron or molybdenum, have only one chemical bond and are therefore limited to forming complexes. So strictly speaking, boron and molybdenum cannot be called chelated minerals, but they are still usually sold as chelated minerals on the market. In agriculture, the chelates we usually come into contact with are EDTA, EDDHA, citric acid, amino acids, humic acid and other chelates.
Chelated trace elements
It is very important that chelates are molecules with a neutral charge. Because the stomata on plant leaves are negatively charged, positively charged molecules trying to penetrate the plant will be bound at the entrance of the stomata, slowing the absorption of trace nutrients. For example, calcium and magnesium both have a +2 charge. Soil is usually negatively charged, especially clay. This means that calcium and magnesium may react with the soil, become insoluble, and unavailable to plants. Crops are more easily absorbed by crops in the form of neutrally charged chelates.
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EDTA chelated micronutrients
What is ETDA fertilizer?
EDTA chelated fertilizer is a relatively common medium and trace element fertilizer on the market, and it has been on the market for many years. EDTA is a large synthetic molecule that binds very tightly to minerals and resists chemical interactions – this property is ideal for use in soil. Because of this property, it has a wide range of compounding properties, which is a great advantage in compounding as a raw material. However, it is precisely because of this strong bonding property that EDTA chelates release one metal element while holding onto another element after entering the plant. For example, in order to release iron, EDTA chelates must bind to manganese in the plant, causing manganese deficiency. That is, EDTA can quickly solve the nutrient deficiency of one plant while causing nutrient deficiency in another plant. In addition, EDTA is a synthetic molecule, and plants do not use EDTA naturally. It’s a bit like trans-fat; the human body doesn’t know how to deal with it. Plants also don’t know how to deal with and use EDTA, so it usually just stays in the plant and fruit and enters the human body as people eat it, chelating metal elements, causing nutrient deficiencies, which is not good for health. In some areas, there are already relevant policies to restrict the role of EDTA chelate fertilizers.
3. Amino acid chelated trace element fertilizers
What is amino acid fertilizer?
Amino acids are the building blocks of protein. Amino acids are medium-strength chelators. Once inside the plant, the minerals are released, and the remaining amino acids that form a protective shell are used by the plant as a source of water-soluble nitrogen. They can do this because amino acids are recognized as building blocks by plants and are used in almost every tissue of the plant. Glycine chelate (also called glycinate) is a type of amino acid chelate. Glycine is the smallest amino acid with a molecular weight of only 75, so it is easier to produce small end products that pass through stomata than other larger molecules, thereby enhancing plant absorption. However, as a medium-strength chelating agent, the stability of amino acids is not as good as EDTA. When used as a fertilizer, it is necessary to pay attention to the chemical reactions between elements. For example, amino acid chelated iron, copper, calcium, etc. should not be compounded or used together with phosphate fertilizers.
In summary, the differences between EDTA chelated fertilizer and amino acid chelated fertilizer in agricultural use are as follows:
- Although EDTA chelated trace elements with strong chelating ability are easily absorbed by plants, they are not easily released when transporting chelated elements in plants, resulting in a shortage of another trace element in plants. The amino acids in amino acid fertilizers are small molecule nutrients that can be directly used by plants without being converted, so the auxiliary effect is more obvious.
- The price of EDTA chelated fertilizer is much higher than that of amino acid chelated trace element fertilizer. Amino acid fertilizer price is indeed much more economical.
- EDTA chelated micronutrient itself is too stable and not easy to degrade in the environment. It will also chelate harmful heavy metal ions in the soil, which has the risk of increasing harmful heavy metals such as cadmium, lead, chromium, etc. in agricultural products, causing harmful heavy metals in agricultural products to exceed the standard. Amino acid chelated trace elements have moderate chelation stability and are easily decomposed and utilized by crops. As chelating agents, amino acids are easily decomposed in the soil without residue, without the risk of acidification and salinization of the soil, and can also regulate and stimulate crop growth. It is being chosen by more and more organic farms and fertilizer dealers.
