Potassium chloride (commonly referred to as muriate of potash or mop) is the most common potassium source used in agriculture, accounting for about 95% of all potash fertilizers used worldwide. Mop has a high nutrient concentration and is therefore relatively price competitive with other forms of potassium. mop chemical composition moisture % by weight (maximum) – 0.5 %water soluble potash (as k2o) per cent by weight (minimum) – 60% sodium as NaCl percent by weight (on dry basis) maximum – 3.5 % brand: tak agro imported from Ukraine crops pastures, sugar cane, fruit trees, vegetables, and other field crops.