Zinc (Zn) in crops: role, deficiency signs and how to correct it

Zinc is a micronutrient the crop needs for its growth hormone (auxin), for more than a hundred enzymes, for chlorophyll and for healthy pollen. A zinc-short crop has small, narrow, pale new leaves, short internodes and poor tillering or flowering. Zinc is the most common micronutrient shortage in Indian soils, especially in alkaline, calcareous and low organic matter fields.

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

What zinc does in the plant

• Helps the plant make auxin, the hormone that drives cell growth and normal leaf size.
• Switches on many enzymes for energy, protein building and sugar use.
• Needed for chlorophyll formation, so the leaf stays green.
• Keeps cell membranes healthy, which helps roots hold nutrients and resist stress.
• Supports pollen and seed formation, so it matters at flowering and grain fill.

How zinc moves in the plant

Zinc moves only a little inside the plant, so a shortage shows first on young and middle leaves. Once a leaf is formed short of zinc, it does not recover; only the new growth after correction looks normal.

Signs of zinc deficiency

• Pale or yellow patches between the veins of young leaves, while veins stay green.
• Small, narrow leaves, often bunched at the tip (little leaf or rosetting).
• Short internodes, so the plant looks stunted and bushy.
• Rusty brown spots on older leaves of paddy a few weeks after transplanting.
• A white or pale band on both sides of the midrib in young maize leaves.
• Delayed flowering and maturity, poor grain filling.

Crop by crop

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

Where and why it happens

In India, an ICAR survey of more than two lakh soil samples found 51.2% of soils short of zinc, counting hidden shortages.

• Alkaline and calcareous soils, common in Saurashtra and much of Gujarat.
• Soils low in organic matter.
• Fields where the topsoil was removed in land levelling.
• Heavy, repeated use of phosphate fertilizers such as DAP.
• Flooded paddy soils.
• Cold, wet weather early in the season, which slows root uptake.
• Sandy soils that are low in zinc to start with.

How it works with other nutrients

• High phosphorus can lower zinc uptake, so DAP-heavy fields often show zinc shortage.
• In high pH and calcareous soils zinc becomes less available.
• Very high zinc can lower iron uptake.
• Nitrogen raises the crop's need for zinc, so a well-fed crop shows zinc shortage sooner.
• See nutrient interactions.

What happens if it is not managed

• Stunted plants and fewer tillers or branches.
• Late and weak flowering, poor fruit and grain set.
• Lower grain weight and a poorer harvest even when NPK was applied.
• Grain and fodder with less zinc, which matters for people and animals who eat them.
• See the full picture of what unmanaged shortages cost.

How to confirm it

• Look at the youngest leaves first: small, narrow, pale leaves point to zinc.
• Rule out pests, virus and herbicide drift, which can look similar.
• Ask for a DTPA zinc soil test, which is part of the Soil Health Card test.
• A leaf test at the right stage confirms what the crop actually took up.
• Spray a small strip and compare the new growth after one to two weeks.

How to correct it

• Soil application of zinc sulphate before or at sowing in deficient fields. Do not mix it with phosphate fertilizers in the same bag or tank.
• Foliar spray of zinc sulphate or a chelated zinc on the standing crop for quick correction of new growth.
• Zinc-coated urea or zincated fertilizers where available.
• Seed or seedling root dip for crops where your agriculture department advises it.
• Zinc solubilising bacteria and organic manure to free zinc already locked in the soil and keep it available.
• Take the dose from your soil test report, the product label or your agriculture officer.

Too much zinc

• Zinc excess is rare in fields. It can happen near industrial waste or after repeated heavy doses.
• Too much zinc can cause iron shortage, seen as yellow young leaves.

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.