Among the many potassium fertilizers available today, four products are most commonly used in agricultural production: Potassium Nitrate (KNO₃), Mono Potassium Phosphate (MKP), Potassium Chloride (MOP/KCl), and Potassium Sulfate (SOP/K₂SO₄). Each has distinct nutrient characteristics, application scenarios, and limitations. Understanding these differences helps growers optimize fertilizer efficiency, avoid nutrient imbalances, and achieve better economic returns.