Research on the sources of nitrate in agricultural watershed in karst areas of Southwest China based on stable isotopes
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Research on the sources of nitrate in agricultural watershed in karst areas of Southwest China based on stable isotopes

Linyan Pan 1, Runhan Han 2, Zhaohui Luo 3*
1 Guangxi Normal University
2 Guilin University of Technology
3 Shunde Polytechnic University
*Corresponding author: ann-fred@163.com
Published on 4 July 2025
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AEI Vol.16 Issue 7
ISSN (Print): 2977-3911
ISSN (Online): 2977-3903
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Abstract

The agricultural watersheds in the karst regions of Southwest China face severe nitrate pollution, but research on its sources and transport mechanisms remains limited. This study focuses on the Mudong River watershed in Guilin, Guangxi. Water samples were collected from 2020 to 2025 and analyzed for hydrogen, oxygen, nitrogen, and oxygen isotopes as well as nitrogen concentrations, in combination with the SIAR model. Results show that total nitrogen is mainly in the form of nitrate, with δ¹⁵N-NO₃⁻ and δ¹⁸O-NO₃⁻ values ranging from -1.651‰ to 14.993‰ and 0.037‰ to 19.266‰, respectively. Nitrification dominates nitrate transformation, with soil nitrogen and animal manure/domestic wastewater as the primary sources. This research provides a scientific basis for nitrate pollution control in agricultural watersheds of karst regions.

Keywords:

nitrogen and oxygen isotopes, nitrate, hydrogen and oxygen isotopes, karst

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Pan,L.;Han,R.;Luo,Z. (2025). Research on the sources of nitrate in agricultural watershed in karst areas of Southwest China based on stable isotopes. Advances in Engineering Innovation,16(7),21-28.

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Cite this article

Pan,L.;Han,R.;Luo,Z. (2025). Research on the sources of nitrate in agricultural watershed in karst areas of Southwest China based on stable isotopes. Advances in Engineering Innovation,16(7),21-28.

Data availability

The datasets used and/or analyzed during the current study will be available from the authors upon reasonable request.

About volume

Journal: Advances in Engineering Innovation

Volume number: Vol.16
Issue number: Issue 7
ISSN: 2977-3903(Print) / 2977-3911(Online)