Aerial photography of potash evaporation ponds, Carlsbad, New Mexico, USA. Potash is a mined salt containing potassium. This mine produces muriate of potash (potassium chloride) which contains 60% potash. Potash is used as a fertiliser for crops, promoting plant growth and quality. The brine is pumped from underground to the surface, where it is collected in large ponds. The water from the brine is evaporated over time, allowing the salt to crystallise. The water is dyed blue to reduce the amount of time it takes to crytallise the salts, as darker water absorbs more sunlight and heat.