Phosphorus Management in High-Yield Systems

The discovery and development of phosphorus (P) and P fertilizers provide context for current management conventions. Average crop yields were stagnant before the Green Revolution but have steadily increased since. This, along with conventional P management, has resulted in widely depleting soil P levels. Improved technology and management are needed to meet the increasing P demand. Modern hybrids and cultivars have different P demand and uptake patterns that require changes in conventional P fertilizer placement and timing. Phosphorus fertilizer recommendations based on soil analysis remains valid, but evidence suggests a need for recalibrating soil test P (STP) critical levels (the STP concentration at which a response to P fertilizer would not be expected) and P fertilizer rates to accommodate high-yield scenarios. Considering higher P fertilizer rates as a single solution poses environmental challenges, highlighting the need for improved P use efficiency (PUE). Phosphorus fertilization approaches that have the potential to improve PUE and enable high yields include crop-specific precision placement of P, informed timing of P fertilizers, and new enhanced efficiency sources of P fertilizer. This paper examines these management approaches from historical, production, and environmental perspectives in modern cropping systems.