Spatiotemporal analysis of anthropogenic phosphorus fluxes in China

Anthropogenic phosphorus supports food systems while have caused water pollution and posed challenges to the ecosystems. The increasing socioeconomic interactions between regions and systems have added more complexities to manage the sustainability of effective phosphorus use that requires joint analyses of multiple regions or multiple systems of phosphorus flow. This study builds a framework to systematically model the phosphorus fluxes in China based on material flow analysis. This model consists of phosphorus industrial system, agricultural planting system, rural residential system, urban residential system, large-scale livestock breeding system and household livestock breeding system. This study further explored the temporal and spatial characteristics of phosphorus fluxes in terms of phosphorus utilization efficiency and water load during 1995-2015. The results showed that the total amount of phosphorus input in China had increased nearly 1.78 times during 1995-2015, of which about 85% is used for fertilizer production. The phosphorus utilization rates of urban residential and large-scale livestock breeding systems remained low with a declining trend, dropping to 5%. The phosphorus water load peaked and declined during the study period. Among them, the phosphorus water load in large-scale and household livestock breeding systems accounted for more than 60% of the total. In spatial dimension, Southwest China is the region with the largest input of phosphorus, about 375.33 × 10⁴ t, while Northeast China is the region with the largest phosphorus water load, about 28.06 × 10⁴ t.