Iron (Fe)

Role in plants

Iron is essential for chlorophyll formation (indirectly), electron transport, and many redox enzymes. It is largely immobile in the plant.

Deficiency symptoms

• Interveinal chlorosis on young leaves
• Leaves may become almost white in severe cases
• Reduced growth and weak new shoots
• Common at high pH or high bicarbonate conditions

Toxicity symptoms

• Bronzing and speckling
• Root damage in waterlogged/acid conditions
• Induced deficiencies of other micronutrients

Natural sources

• Soil minerals (iron oxides/hydroxides)
• Organic matter complexes

Fertiliser sources

• Chelated iron: Fe-EDTA, Fe-DTPA, Fe-EDDHA
• Iron sulphate (limited at higher pH)

Plant uptake forms

• Fe²⁺ / Fe³⁺ (rhizosphere-dependent)
• Chelated Fe in solution