Metal ions are essential minerals for plants' growth. They are required insmall amounts, and thus are refered to as 'Micronutrients'. Their deficiency results in yellowing of leaves, retarded growth and overall low quality of the crop.
Chelated compounds are more stable than non-chelated compounds. Therefore, metallic chelates are widely used in agriculture as micronutrient fertilizers to supply plants withIron, Manganese, Zinc and Copper. The most common chelate used in agriculture is EDTAHow Does a Chelate Work?
Metal chelation is important because it makes metal ions more available for uptake by plants.
OH-ions are abundant in alkaline or neutral soils and soil-less media. Positively charged metal ions, such as Zn+2, Mn+2, Cu+2and Fe+2, readily react with negatively charged hydroxide ions (OH-), making them unavailable to plants.
The ligand (a molecule that binds to a central metal atom) coats the metal ion, protecting it from the surrounding OH-ions. The complex can then be easily absorbed by the plant, where it is being degraded and consumed as micronutrients.