A review of phosphorus management through the food system: identifying the roadmap to ecological agriculture

The possibility of future phosphorus (P) scarcity and the requirement to improve the environment quality necessitates P management for achieving ecological agriculture. The study reviews different methods of analyzing P flows through the food system including the human activities of fertilizer manufacturing, crop cultivation, crop processing, livestock breeding, resident consumption, etc. to identify the priority management. It is revealed early studies analyzed P flows mainly based on monitoring and geography information system, or combined with the soil erosion and P loss formula, which calculated the P loads but could not be used to trace the sources of these flows. Then the mass-balance or the input-output balance method was applied based on the mass balance principle, tracking and analyzing P utilization and transformation ineffectively, and likely leading to ineffective P management. A substance flow analysis of P was suggested to do such an inquiry. Apart from substance flow analysis, there are also several studies assessing the environmental impacts with P use in the food system based on life cycle assessment. These studies have focused mainly on quantifying P discharge from the systems and identifying the key sources and paths of pollution, while often ignored the P management or just analyzed from only ecological point. For achieving the ecological agriculture, P management has to face more challenges, such as the appreciate method from the life cycle aspects, more comprehensive system defined, adequate and high-quality data, more time-and-spatial scale, etc.