Land use mediates riverine nitrogen export under the dominant influence of human activities

Binhui Chen, Scott X. Chang, Shu Kee Lam, Jan Willem Erisman, Baojing Gu*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Riverine nitrogen (N) export is a crucial process that links upstream and downstream ecosystems and coastal zones. However, the driving forces of riverine N export that is closely related to water N pollution are still not well understood. In this study, we used a mass balance approach to quantify the sources of N discharge and analyzed the effect of land use composition on riverine N export, taking Zhejiang Province, China as a case study. We found that the total reactive N discharge to rivers in Zhejiang increased from 0.22 to 0.26 Tg yr-1 from 2000 to 2015. At the watershed scale, our estimate of N export agrees well with the monitored riverine N concentration in the eight major watersheds in Zhejiang. Direct discharge of domestic wastewater and effluents from wastewater treatment plants are dominant sources of riverine N export, followed by agricultural non-point sources. Although riverine N export increases with the increasing proportion of urban and agricultural land uses, we did not find any relationship between land use change and changes in riverine N export. This suggests that the dominant factor affecting riverine N export should be human activities (e.g. wastewater discharge and fertilization level), while land use only mediates riverine N export.

Original languageEnglish
Article number094018
JournalEnvironmental Research Letters
Volume12
Issue number9
DOIs
Publication statusPublished - 18 Sept 2017

Funding

This work was supported by National Science Foundation of Zhejiang Province (LR15G030001), National Natural Science Foundation of China (41773068) and the Open Fund of Key Laboratory of Nonpoint Source Pollution Control, Ministry of Agriculture, China (1610132016005).

FundersFunder number
Key Laboratory of Nonpoint Source Pollution Control
Ministry of Agriculture, China1610132016005
National Science Foundation of Zhejiang ProvinceLR15G030001
National Natural Science Foundation of China41773068

    Keywords

    • buffer zone
    • human activities
    • land use change
    • mass balance
    • scale effect
    • source apportionment

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