Soil potassium depletion in global cereal croplands and its implications.

Nitrogen (N), phosphorus (P) and potassium (K) are of the most essential nutrients for crop production, and inputs of their fertilizers have been a direct and effective way to replenish their removal from crop harvest. However, the global soil K status is scarcely documented. This study attempts to evaluate the soil K deficit in global cereal croplands and potential effects of better K fertilizer management.