Potassium as a Key Nutrient for Sustainable Cereal Production: A Review

Abstract

Potassium (K) is an essential macronutrient for cereal crops and contributes to growth, yield formation, grain quality and tolerance to environmental stresses. This review summarises the role of K in sustainable cereal production, with emphasis on physiological functions, soil dynamics, crop uptake, deficiency symptoms, nutrient interactions, losses and management options. Potassium supports enzyme activation, photosynthesis, assimilate translocation, stomatal regulation, osmoregulation, protein and carbohydrate metabolism, and ionic balance. In soil, K occurs in solution, exchangeable, non-exchangeable and mineral-bound forms, and its availability is influenced by texture, clay mineralogy, moisture, temperature, pH, cation exchange capacity, organic matter and management practices. Cereal crops differ in K demand and response; rice requires K throughout vegetative and reproductive phases, wheat responds strongly during tillering and grain development, and maize benefits from balanced K and phosphorus supply. Inadequate K nutrition may cause marginal chlorosis, necrosis, weak stems, poor root development, reduced grain filling and hidden hunger before visible symptoms appear. Major K losses occur through harvested produce, residue removal, erosion, runoff and leaching, particularly in coarse-textured or intensively cultivated soils. Sustainable K management should integrate appropriate fertiliser source, rate, timing and placement with split application, foliar supplementation where root uptake is limited, crop-residue recycling, organic amendments, and monitoring of exchangeable and non-exchangeable K pools. These approaches can improve K-use efficiency, maintain soil fertility and support resilient cereal-based production systems.