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