This term referred to the fertilizer value of wood ashes. Researchers now know K 2 O is not the effective potassium compound in chemical fertilizers. However, as a carryover from the way chemists expressed analytical results at the turn of the century, the fertilizer industry still uses the expression to designate the true compound. Potassium and plant nutrition Potassium is referred to as the third major plant nutrient. Nitrogen and phosphorus are the other two major nutrients and historically were deficient in many Missouri soils.
Potassium is an important plant nutrient for several reasons.
Is associated with stronger stalks and stems, thus reduces lodging. Assists in more than 60 enzyme systems affecting metabolism. Assists in photosynthesis and conversion of sugars to starches and cellulose. Aids in translocation of food within a plant. Increases protein, starch, and oil content of plants.