Manganese (Mn)
Role in plants
Manganese is required for photosynthesis (water-splitting complex), enzyme activation, and nitrogen metabolism.
Deficiency symptoms
- Interveinal chlorosis with fine speckling (young to mid leaves)
- Reduced growth
- More common at high pH
Toxicity symptoms
- Brown/black speckling and necrotic spots
- Leaf crinkling
- Root inhibition, often in acidic soils
Natural sources
- Soil minerals, especially under acidic conditions
- Organic matter complexes
Fertiliser sources
- Manganese sulphate
- Chelated Mn products
Plant uptake forms