Potassium Used in Fertilizers

Potassium is a common element in Earth's crust and is vital for both plants and animals. Plants extract the potassium they need from the soil; fertilizers replace the potassium extracted by plants to help farmers sustain high productivity.

Types

• Together with phosphorus and nitrogen, potassium is one of the three most common nutrients in fertilizers. Common fertilizer compounds that contain potassium include potassium nitrate, potassium chloride and potassium sulfate; manure is another source of potassium. Excess potassium fertilizer will do nothing for the plant, so it's important not to apply more than plants actually need.

Function

• According to the University of Minnesota Extension, the role of potassium in plant growth is not yet fully understood. It's clear, however, that without sufficient potassium, plants suffer from stunted growth and tissue damage; the primary symptom is yellowing or browning around the edges of the leaves. While potassium is common in soils, most of it is trapped in mineral form and will only become available over time through weathering.

Considerations

• Potassium chloride is obtained from mineral or brine deposits. Potassium nitrate, by contrast, is produced by reacting ammonium nitrate with potassium hydroxide or potassium chloride. Adding potassium chloride to sulfuric acid produces potassium sulfate.