Analysis of phosphorus concentration in a subtropical river basin in southeast China: Implications for management

The study analyzed the factors that led to high total phosphorus (TP) concentrations in the Jiulong River Basin, a subtropical basin with intensive agricultural activities. The results showed that the TP in the river basin originated mainly from non-point sources. Livestock (including poultry) breeding was the main contributor, accounting for 35% of the total load in 2003 and 43% in 2007. The close correlation between TP load and environmental capacity explained the spatial variability of TP concentration in the entire watershed. There was also significant correlation between flow and water quality from 2003 to 2007. Key areas with high concentrations of TP were further identified and evaluated. The results suggest that livestock breeding should be controlled to reduce the TP load. The water requirement for sustaining ecosystem functions should also be addressed.