Optimizing nitrogen management for pollution control in Lake Baiyangdian following water replenishment

Peixian Hao; Jing Yang; Xia Liu; Maryna Strokal; Dianneke van Wijk; Zhaohai Bai; Lin Ma

doi:10.1016/j.jenvman.2024.123374

Optimizing nitrogen management for pollution control in Lake Baiyangdian following water replenishment

J Environ Manage. 2024 Nov 22:372:123374. doi: 10.1016/j.jenvman.2024.123374. Online ahead of print.

Authors

Peixian Hao¹, Jing Yang², Xia Liu³, Maryna Strokal⁴, Dianneke van Wijk⁵, Zhaohai Bai⁶, Lin Ma⁷

Affiliations

¹ Key Laboratory of Agricultural Water Resources, Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetic and Developmental Biology, The Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang, 050021, Hebei, China; University of Chinese Academy of Sciences, 19 A Yuquan Road, Shijingshan District, Beijing, 100049, China.
² Key Laboratory of Agricultural Water Resources, Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetic and Developmental Biology, The Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang, 050021, Hebei, China.
³ School of Mathematics and Science, Hebei GEO University, 136 Huai'an Road, Shijiazhuang, 050031, Hebei, China.
⁴ Water Systems and Global Change Group, Wageningen University and Research, Droevendaalsesteeg 4, Wageningen, 6780, PB, the Netherlands.
⁵ Netherlands Institute of Ecology (NIOO-KNAW), Department of Aquatic Ecology, P.O. Box 50, Wageningen, 6700, AB, the Netherlands.
⁶ Key Laboratory of Agricultural Water Resources, Hebei Key Laboratory of Soil Ecology, Center for Agricultural Resources Research, Institute of Genetic and Developmental Biology, The Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang, 050021, Hebei, China. Electronic address: baizh1986@126.com.
⁷ State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, 210023, China.

PMID: 39579567
DOI: 10.1016/j.jenvman.2024.123374

Abstract

Eutrophication is an ecological process showing the state shift of a lake. This shift could be triggered when the external nitrogen (N) loads exceed N thresholds. Meanwhile, external water inputs and the resulting changes in lake water depth could affect N thresholds. Thus, the shift towards eutrophication may occur more quickly when the N thresholds decrease. Lake Baiyangdian is located in the North China Plain and plays an essential role in ecosystem service provision. However, this lake may have seen a decrease in the N threshold decrease due to frequent water replenishment since 2015. In this study, we compared the external N loads to Lake Baiyangdian with the N thresholds from 2012 to 2017. For this, we considered the effects of water replenishment by linking the MARINA-Lakes and the PCLake + models. Then, we assessed how N thresholds could be met by external N loads from sub-basins of Lake Baiyangdian under 2017 and different N management cases, including improved crop yield and efficiency (S1), improved sewage treatment (S2), improved manure management (S3), and combined options (S4). Results indicate that a 45% reduction in river export of N to Lake Baiyangdian was found from 2012 to 2017. Agricultural sources (fertilizer and manure) accounted for 59% of river exports of N in 2017. River N exports to the lake are projected to be reduced by 13-67% under the four cases. In 2017, the N-load response curve exhibited hysteresis with a 56-87% decrease in N thresholds compared to 2012. Measures in S4 can help to reduce external N exports to Lake Baiyangdian below the N thresholds. Our study emphasizes the importance of combined N management strategies to mitigate the eutrophication risk of the lake. These results offer valuable insights for N management in lake basins experiencing increasing water depth resulting from water replenishment.

Keywords: Baiyangdian; Basin N management; Nitrogen threshold; Water replenishment.