These are required in small quantities by the plant, but they are still essential for plant health and production. The trace elements are Copper (Cu), Iron (Fe), Manganese (Mn), Molybdenum (Mo) and Zinc (Zn) and without them plants will exhibit a variety of deficiency symptoms.
Iron Chelates are organic elements that bind the iron like a claw, so that the iron remains available in the solution, thus available to the plant. A plant can only absorb nutrients that are dissolved in water. Fertilization of iron is always dosed in chelated form. This, because iron easily precipitates when in contact with other elements. This precipitation is prevented by adding iron to the solution through chelates.
Different types of iron chelates
There are different types of iron chelates, all with their own characteristics. The strength of the chelate is depending heavily on the pH level of the solution, for example in the substrate mats or in the soil. Several chelates are present on the market to suit every pH level in the root environment.
Stability in relation to the pH
- EDTA is the least strong chelate on the market. EDTA iron chelates are mainly recommended for foliar fertilization, since they are not perceived stable enough to be added to a fertilizer tank.
Ferric EDTA, EDTA Ferric, Ferric ethylenediaminetetraacetic acid
Fe EDTA 13% - water soluble
1. For the correction of iron defiency in agricultural, horticultural, and fruit crops. Recommended for foliar application or application to acid soils.
2. Apply where there is a recognised need. Do not exceed the appropriate dose rate
4. Compatilble with all other chelates and many crop care chemicals. Also compatible with solutions containing soluble phosphates such as liquid feeds and foliar fertilisers
Rate of application:
First check the pH of the nutrient solution, and if necessary adjust this to 5 - 6, than add Fe EDTA at a rate of 20g per 1000 L of the nutrient solution
Dissolve the appropriate amout of Fe EDTA in a convenient volume of water (1 - 3kg per hectare or 100g per 18 L water sprayer) and apply to the soil as a coarse, low pressure spray
The amount of Fe EDTA to be applied should be mixed with a volume of water appropriate to the crop leaf area not exceeding a solution concentration of 0.1% or 100g per 100L water. Coat the leaves and stems with a thin film of moisture with little or no run-off, and in late afternoon.