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Muriate of Potash (MOP / KCl)

Muriate of Potash (MOP), chemically potassium chloride (KCl), is India's principal straight potassic fertiliser. The product carries 60% K2O and is fully water soluble. India has no commercial potash reserves and is dependent on imports; Indian Potash Limited and major fertiliser companies handle distribution. MOP is regulated under the FCO and the Nutrient-Based Subsidy regime.

Composition

  • Nutrient content: 60% K2O (as KCl, ~50% elemental K)
  • Appearance: reddish-pink granules, 2-4 mm
  • Solubility: fully water soluble

The pink colouration is from trace iron impurities in the parent sylvinite ore. A purer white grade is produced by recrystallisation for specialty fertigation use.

Mode of action

MOP dissolves rapidly in soil moisture to release K+ and Cl- ions. Potassium is then held on cation-exchange sites and taken up by roots through active transport. The chloride content, while inert for most cereals, makes MOP unsuitable for chloride-sensitive crops such as tobacco, grapes, mango and chillies under salinity, where Sop Water Soluble Paddy (sulphate of potash) is preferred.

Target use and dose

MOP is applied to cereals, sugarcane, cotton and oilseeds as basal and top-dressing potash. In paddy, a typical schedule places potash in two or three splits across transplanting, active tillering (Paddy Tillering Top Dressing) and panicle initiation. For deficiency correction, a one-shot soil application of MOP can be used to restore plant potassium status quickly.

Subsidy and supply

India imports nearly all its MOP requirement, primarily from Canada, Russia, Belarus and Jordan, channelled through Indian Potash Limited and major importers. The retail price is regulated under NBS, with subsidy notified per tonne of K2O.

See also: Urea, Dap, Sop Water Soluble Paddy, Organic Potash, Nano Potash Paddy.

References

  1. Muriate of Potash MOP 60% K2O. Gujarat State Fertilizers & Chemicals Limited.
  2. Fertilisers Division. Indian Potash Limited.