Estimation of Total Phosphorus Load to Poyang Lake Basin by Watershed Division.

W ith the fast growth of human population, socio-economic development and resource exploitation, significant alterations have unfolded within the Poyang Lake ecosystem, thrusting environmental concerns to the forefront. Presently, total Phosphorus levels in the Poyang Lake region surpass established standards, and this concentration continues to surge, bearing witness to the progressive deterioration of the lacustrine biosphere. Designated as a priority demonstration area for national ecological civilization construction and Yangtze River protection and restoration, phosphorus pollution in the Poyang Lake Basin has emerged as a critical and urgent challenge in Jiangxi Province s management of its aquatic ecological environment. Based on the technological method of watershed zoning in the pollution source census, it presents the estimation of the total phosphorus pollution load and the quantitative analysis of phosphorus pollution sources entering the lake. The results show that the total phosphorus pollution load entering Poyang Lake in 2021 reached 14 900 tons, with the primary pollution originating from the land-based input, accounting for 87.73% of its contribution ; in order of contributing weight, the sources of pollution within the lake primarily arose from endogenous releases (5.52%) and soil erosion (4.60%). Our analysis ranks the pollution sources in descending order of contribution weight as follows: Livestock farming (48.63%) > Urban living (20.01%) > Cultivation (9.71%) > Aquaculture (7.37%) > Endogenous r elease (5.52%) > Soil erosion (4.6%) > Industrial enterprises (1.12%) > Rural domestic (0.89%) > Migratory bird droppings (0.46%) > Tourism (0.12%).Notably, livestock farming emerges as the primary contributor to agricultural surface contamination concerning the total phosphorus indicator. Regarding spatial distribution, high-contributing watersheds of total phosphorus load are primarily concentrated in the Ganjiang River Gathering Area and the Binhu Area, with the contribution proportion of 50.67% and 25.92%, respectively, and concentrated production of total phosphorus in the catchment areas of the Fu River and Xinjiang River, with a contribution of 7.64% and 8.34%, the remaining catchment areas generated load into the lake with relatively low intensity, accounting for contributions totaling 7.39%. Moreover, a similar contributing structure of pollution sources in each sub-region is mainly presented as agricultural sources as the main source, with urban sources as a secondary source. Based on the research findings, it is evidenced that the sources of total phosphorus pollution in Poyang Lake exhibit spatial variability. However, the principal control sources for total phosphorus in the lake show similarities across different regions. To effectively address these concerns and enhance the overall ecological well-being of the Poyang Lake Basin, this paper strongly recommends prioritizing the control of high-contributing watersheds, such as the Binhu District and the Ganjiang Watershed. Mitigating phosphorus pollution effectively would require tailored prevention and reduction strategies, especially focusing on agricultural and urban living. Initiatives such as relocating livestock farming to areas with large environmental capacity, emissions reduction measures, and eco-friendly enrichment. Implementing these measures holds the promise of alleviating the issue of total phosphorus pollution and ensuring the sustainable development of Poyang Lake and the stability of its hydro-ecosystem. [ABSTRACT FROM AUTHOR]