Zinc Sulphate
The cheapest big yield win on many farms. Zinc deficiency is everywhere in Indian soil, and a small dose of zinc sulphate pays for itself several times over.
- Composition
- Zn 21% (heptahydrate) / 33% (monohydrate)
- Form
- White / off-white crystals
- Price
- Low (small dose per acre)
- Best for
- Zinc deficiency — rice, wheat, maize
Overview
Zinc is a micronutrient — needed in tiny amounts — but its shortage is anything but small: zinc deficiency is the most common micronutrient problem in Indian soils, severe in rice–wheat belts, and it shows as small new leaves with pale/white bands between the veins and stunted, bunched growth ("khaira" in rice).
Zinc sulphate is the standard correction. It comes as heptahydrate (21% Zn) or monohydrate (33% Zn); the monohydrate is more concentrated per bag. A modest soil application every couple of years, or a foliar spray for a quick rescue, corrects the deficiency at very low cost.
What it is and when to reach for it
- A micronutrient fertiliser for zinc-deficient soils — most needed in rice, wheat and maize, and on levelled, high-pH or sandy fields.
- A soil test or the classic symptom (pale banded new leaves, bunched growth) tells you when it is worth applying.
- One soil application often lasts two to three seasons, so it is not an every-crop cost.
How to apply it well
- Soil: apply about 10 kg/acre of zinc sulphate heptahydrate (or ~4–5 kg of monohydrate) as basal, once every 2–3 years, mixed well into the soil.
- Foliar rescue: spray 0.5% zinc sulphate heptahydrate (0.5 kg in 100 L water) — add half as much agricultural lime to a foliar mix to avoid leaf scorch.
- In rice nurseries and transplanted rice, correcting zinc early prevents the classic mid-tillering "khaira" stall.
Common mistakes
- Mixing zinc sulphate directly with DAP or phosphate fertiliser — phosphorus locks up the zinc; apply them separately.
- Spraying plain zinc sulphate at high strength without lime, scorching the leaves.
- Applying zinc every season out of habit — once every few years is usually enough, so a soil test saves money.
Organic alternative
FYM + zinc-solubilising bacteria
Heavy FYM plus a zinc-solubilising biofertiliser slowly frees native soil zinc — a supporting measure, though a severe deficiency still needs zinc sulphate.
Crops it is used on
Open a crop for its full nutrient schedule.
Common questions
Which crops need zinc the most?
Rice is the classic case (zinc deficiency causes "khaira"), followed by wheat and maize. Zinc shortage is worst on levelled, high-pH, sandy or intensively cropped rice–wheat soils. A soil test confirms it, but the banded pale new leaves are a strong clue.
Can I mix zinc sulphate with DAP?
No — do not mix them together. Phosphorus reacts with zinc and locks it up, so both are wasted. Apply zinc sulphate to the soil separately from your phosphate fertiliser, or use a foliar zinc spray instead.
How do I make a zinc foliar spray?
Dissolve 0.5 kg of zinc sulphate heptahydrate in 100 litres of water (0.5%) for one acre. To avoid leaf scorch, many farmers add about 0.25 kg of agricultural lime to the mix. Spray in the cool morning or evening.
Composition and doses follow ICAR / Soil Health Card guidance; prices are the notified subsidised rates for the season shown and are guidance, not a quote. A soil test for your field always beats a general rate. See our editorial policy.