Resolving the global phosphorus (P) paradox—ensuring food production for growing population while preventing geological resource depletion and aquatic degradation—demands innovative strategies that move beyond simply reducing environmental discharges. Current solutions often overlook the synergistic benefits of source control and circular economy enhancement, leading to fragmented sustainability assessments. Here we investigate China's Yangtze River Economic Belt (YREB), a global socioeconomic nucleus exhibiting archetypal P imbalances. By integrating seven decades (1950-2020) of substance flow analysis with a novel systemwide evaluation module, we systematically quantified the sustainability potential of 15 interventions across production, processing, consumption, and waste disposal stages. Our finding revealed peak-plateau P flow dynamics characterized by a critical transition from organic nutrient recycling to inorganic P rock dependency (11.5 Mt/yr). This shift has accelerated geological reserve depletion to less than 30 years while driving annual environmental discharges exceeding 2.65 Mt, particularly in socioeconomic hubs intersecting major hydrological networks. Forward-looking scenarios for 2050 indicate that comprehensive waste valorization (S4) could more than double regional P reserve longevity (+119.8%), while synergistic agricultural reform (S2) might halve peak environmental losses. This systemic mineral provisioning-water security framework provides a transferable policy design paradigm for P-vulnerable basins worldwide that face similar sustainability paradoxes.
