Iron (Fe) in crops: role, deficiency signs and how to correct it

Iron is a micronutrient the crop needs to make chlorophyll and to run photosynthesis and respiration. An iron-short crop shows yellow young leaves with a fine net of green veins, and in severe cases the new leaves turn almost white. Iron shortage is usually not a lack of iron in the soil but iron locked up in alkaline, calcareous or waterlogged soils.

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

What iron does in the plant

• Needed to make chlorophyll, though it is not part of the chlorophyll molecule.
• Part of the proteins that carry energy in photosynthesis and respiration.
• Needed in legume nodules for nitrogen fixation.
• Part of enzymes that protect the plant from stress damage.

How iron moves in the plant

Iron does not move from old leaves to new ones, so the youngest leaves turn yellow first while older leaves stay green.

Signs of iron deficiency

• Young leaves turn pale yellow while the veins stay green, giving a fine green net.
• In severe cases young leaves turn white or papery, with brown dead patches.
• Older leaves stay green.
• Shoots grow weak and short; fruit trees show dieback of twigs.
• Symptoms are often patchy, worst in low spots and wet parts of the field.

Crop by crop

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

Where and why it happens

In India, an ICAR survey of more than two lakh soil samples found 19.2% of soils short of iron, counting hidden shortages.

• Calcareous soils with free lime, where iron is locked up by high pH and bicarbonate (lime-induced chlorosis).
• Over-irrigated or waterlogged fields, where roots cannot breathe.
• Irrigation water high in bicarbonate.
• Very high phosphorus, manganese, copper or zinc.
• Cold soil early in the season.

How it works with other nutrients

• High lime and high pH are the main cause of iron chlorosis.
• Excess phosphorus, manganese, zinc or copper can lower iron uptake.
• Iron and manganese compete: correcting one heavily can show the other.
• Good organic matter keeps iron in forms roots can use.
• See nutrient interactions.

What happens if it is not managed

• Less chlorophyll, so less food is made and growth slows.
• Weak flowering and fruit set in fruit crops.
• Fewer and weaker nodules in legumes, so less nitrogen fixed.
• Small fruit and twig dieback in orchards that suffer year after year.
• See the full picture of what unmanaged shortages cost.

How to confirm it

• Check the youngest leaves: a yellow leaf with a fine green vein net points to iron.
• Note whether the problem is worse in wet or low spots and after heavy irrigation.
• A soil test for pH, free lime and DTPA iron helps; a leaf test confirms.
• Spray a few plants with an iron product and see whether the new leaves green up.

How to correct it

• Improve drainage and avoid over-irrigation first; waterlogging alone can cause iron chlorosis.
• Foliar sprays of ferrous sulphate or chelated iron green up new leaves. More than one spray is usually needed.
• In high pH soils, iron chelates made for alkaline soil hold iron available longer than plain ferrous sulphate.
• Plain ferrous sulphate applied to calcareous soil is often locked up quickly, so it may not work.
• Organic manure, compost and humic substances help keep soil iron available.
• Take the dose from your soil test report, the product label or your agriculture officer.

Too much iron

• Iron toxicity happens in acidic, waterlogged paddy soils, where too much iron dissolves.
• Paddy leaves turn bronze or orange-brown with brown spots, and roots are coated orange.

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.