Manganese (Mn) in crops: role, deficiency signs and how to correct it

Manganese is a micronutrient the crop needs to split water in photosynthesis, to switch on enzymes and to build lignin, which strengthens cell walls against disease. A manganese-short crop shows pale areas between the veins of young leaves with broad green bands along the veins, often with small grey or brown spots. It is common in wheat on light, alkaline soils and after paddy.

By Gafar Laiya and the Gujarat Bio Organics team. Updated November 2026.

What manganese does in the plant

• Splits water in photosynthesis, releasing oxygen; without it photosynthesis slows.
• Switches on enzymes for energy, nitrogen use and growth.
• Helps build lignin, which strengthens cell walls and roots against fungal attack.
• Supports root growth and seed formation.

How manganese moves in the plant

Manganese moves little inside the plant, so young and middle leaves show the shortage first.

Signs of manganese deficiency

• Pale green to yellow areas between veins of young and middle leaves, with broad green bands along the veins.
• Small grey, brown or dead spots on the pale areas.
• Weak, limp plants that look tired in the afternoon.
• In wheat and oats, grey streaks or specks on leaves.
• Poor grain filling.

Crop by crop

More crops and look-alikes: Manganese deficiency symptoms crop by crop.

Where and why it happens

In India, an ICAR survey of more than two lakh soil samples found 17.4% of soils short of manganese, counting hidden shortages.

• Light, sandy, alkaline soils.
• Soils rich in free lime.
• Wheat after paddy, when the soil dries and manganese turns unavailable.
• Soils low in organic matter.
• Over-limed acid soils.
• Dry, well-aerated soils during cool weather.

How it works with other nutrients

• High pH and lime reduce manganese availability.
• Iron and manganese compete: heavy iron can lower manganese uptake, and the reverse.
• Very high magnesium or calcium can lower manganese uptake.
• In acid soils manganese can rise to toxic levels.
• See nutrient interactions.

What happens if it is not managed

• Slower photosynthesis and weak growth.
• Poor grain filling and lower test weight in cereals.
• Weaker cell walls, so the crop is more open to fungal diseases.
• Lower yield even when NPK is adequate.
• See the full picture of what unmanaged shortages cost.

How to confirm it

• Look at young and middle leaves for pale areas with broad green bands along veins and small spots.
• Compare with iron (fine green vein net, no spots) and magnesium (older leaves).
• Ask for a DTPA manganese soil test; a leaf test at the right stage confirms.
• Spray a small strip and compare after one to two weeks.

How to correct it

• Foliar spray of manganese sulphate or a chelated manganese gives the quickest correction.
• Soil application works less well on alkaline soils because manganese is locked up again.
• Repeat sprays may be needed on light soils.
• Building organic matter helps keep manganese available.
• Take the dose from your soil test report, the product label or your agriculture officer.

Too much manganese

• Manganese toxicity happens in acidic and waterlogged soils.
• Signs are brown spots on older leaves, crinkled leaves and, in cotton, crinkle leaf.
• Liming acid soils usually corrects it.

Doses depend on the crop, soil and product, so this page gives methods, not amounts. Take the dose from your soil test report, the product label or your local agriculture officer or KVK. Results differ from farm to farm with soil, weather, crop and management. Farmer experiences on this site are their own reports, not a promise of results.