Natural Origin and Mineral Composition
Polysulphate is manufactured from naturally occurring polyhalite mineral deposits mined from deep geological strata beneath the North Sea. Unlike synthetically blended fertilizers, polyhalite is a single complex crystal salt chemically represented as K2Ca2Mg(SO4)4·2H2O.
Because it undergoes minimal mechanical processing (crushing and screening) without chemical synthesis or acidulation, Polysulphate delivers balanced nutrition with an exceptionally low carbon footprint and low salt index.
- Sulphur (SO3 - 48% / S - 19.2%): Vital for amino acid synthesis, chlorophyll formation, and protein accumulation in oilseeds and pulses.
- Potassium (K2O - 14%): Enhances drought tolerance, stem strength, carbohydrate translocation, and crop quality parameters.
- Magnesium (MgO - 6%): Forms the central atom of the chlorophyll molecule, powering photosynthesis and phosphorus uptake.
- Calcium (CaO - 17%): Strengthens plant cell walls, improves root system architecture, and enhances post-harvest fruit firmness.
Prolonged Release Dynamics and Leaching Resistance
A key agronomic advantage of Polysulphate over conventional soluble sulphate sources (such as ammonium sulphate or potassium sulphate) is its natural prolonged dissolution rate. The multi-mineral crystal structure dissolves gradually over a 50 to 60 day period in soil solution.
This steady nutrient release matches crop uptake curves closely and dramatically curtails sulphate and potassium leaching losses in light sandy soils or heavy monsoon rainfall environments.
- Sustained Nutrient Delivery: Maintains continuous availability of sulphur and calcium throughout prolonged vegetative and flowering cycles.
- Low Salt Index: Suitable for chloride-sensitive crops such as tea, tobacco, grapes, potatoes, and greenhouse vegetables.
- Soil pH Neutrality: Does not cause soil acidification when applied as a basal or top-dressing nutrient source.
Application Methods and Field Recommendations
Polysulphate can be applied as a basal broadcast fertilizer, banded along crop rows during sowing, or incorporated into mechanical fertilizer blends with urea, DAP, or MOP. Its uniform granule integrity prevents dust formation and segregation during pneumatic spreader applications.
It is especially beneficial for high-sulphur-demanding crops including mustard, groundnut, soybean, onion, garlic, sugarcane, and plantation crops across diverse agro-climatic zones.
- Basal Dressing: Incorporate into seedbeds during final land preparation to establish season-long root-zone nutrition.
- Oilseed Enhancement: Improves oil synthesis and seed weight in mustard, groundnut, and sesame crops.
- Organic Farming Suitability: Derived from natural rock without synthetic alteration, making certified grades suitable for organic cultivation systems.
Official source
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Department of Fertilisers, Ministry of Chemicals and Fertilizers ↗Related on KisanPe
Common questions
What four nutrients are contained in Polysulphate?
Polysulphate contains Sulphur (48% SO3), Potassium (14% K2O), Magnesium (6% MgO), and Calcium (17% CaO) in fully bioavailable sulphate forms.
How does Polysulphate reduce nutrient leaching in sandy soils?
Its polyhalite crystal matrix dissolves gradually over 50 to 60 days, matching root uptake curves and preventing flash leaching during heavy rain or irrigation.
Is Polysulphate safe for chloride-sensitive crops?
Yes, Polysulphate has an exceptionally low chloride content and low salt index, making it safe for chloride-sensitive crops like tea, grapes, potato, and tobacco.
General guidance, not personal advice. For your farm, ask your local Krishi Vigyan Kendra or agriculture officer.
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