Managing diffuse phosphorus at the source versus at the sink

Judicious phosphorus (P) management is a global grand challenge and critical to achieving water quality objectives while maintaining food production. The management of point sources has been successful in lowering P inputs to aquatic environments, but more difficult is reducing P discharges associated with diffuse sources. This critical review describes how the metrics of P quantity in kg ha–1 yr–1 and P form can influence decision-making and implementation of diffuse-P management strategies. The review draws upon a number of’current practice’ case studies that span agriculture, cities, and aquatic sectors. These diverse examples from around the world highlight different diffuse-P management approaches and workable options for achieving water quality improvement and wider P sustainability. The diffuse-P management options discussed in this critical review are transferable to other jurisdictions at the global scale.