MOP (Potash) Calculator

Potassium is the nutrient that tends to get forgotten. Many farmers apply urea and DAP faithfully but skip potash, especially where soils were historically rich in it. Years of intensive cropping have changed that in many areas, and potassium deficiency now shows up as scorched leaf margins, weak stems, poor grain filling and more disease.

MOP (potassium chloride) is the cheapest and most common source of potash in India. It contains 60% K₂O, so you need 100 ÷ 60 ≈ 1.67 kg of MOP for every kilogram of K₂O your crop needs.

This calculator converts your K₂O dose into MOP for the whole field and the number of 50 kg bags. For a full N-P-K plan, use the NPK Calculator.

Total K₂O (kg) = K₂O dose × area
MOP (kg) = Total K₂O ÷ 60 × 100
Bags = MOP ÷ 50

Shortcut: MOP ≈ K₂O × 1.67. One 50 kg bag supplies 30 kg K₂O.

• Chloride-sensitive crops. Tobacco, and to some extent potato and some fruit crops, can be sensitive to the chloride in MOP. Potassium sulphate (SOP, about 50% K₂O) is sometimes preferred – change the nutrient percentage to use this calculator for SOP.
• Timing. Potash is usually applied as a basal dose. On light sandy soils it may be split, because potassium can leach.
• Don't skip it on potassium-hungry crops. Banana, sugarcane, potato and many vegetables remove large amounts of potassium.