Please use this identifier to cite or link to this item: http://hdl.handle.net/1893/31680
Appears in Collections:Biological and Environmental Sciences Journal Articles
Peer Review Status: Refereed
Title: Rainfall and conduit drainage combine to accelerate nitrate loss from a karst agroecosystem: insights from stable isotope tracing and high-frequency nitrate sensing
Author(s): Yue, Fu-Jun
Li, Si-Liang
Waldron, Susan
Wang, Zhong-Jun
Oliver, David M
Chen, Xi
Liu, Cong-Qiang
Contact Email: david.oliver@stir.ac.uk
Keywords: Nitrate
Dual isotope
High-frequency
Rainfall events
Karst critical zone
Issue Date: 1-Nov-2020
Citation: Yue F, Li S, Waldron S, Wang Z, Oliver DM, Chen X & Liu C (2020) Rainfall and conduit drainage combine to accelerate nitrate loss from a karst agroecosystem: insights from stable isotope tracing and high-frequency nitrate sensing. Water Research, 186, Art. No.: 116388. https://doi.org/10.1016/j.watres.2020.116388
Abstract: Understanding where nitrate is mobilized from and under what conditions is required to reduce nitrate loss and protect water quality. Low frequency sampling may inadequately capture hydrological and biogeochemical processes that will influence nitrate behavior. We used high-frequency isotope sampling and in-situ nitrate sensing to explore nitrate export and transformation in a karst critical zone. Nitrate was mobilised during light rainfall, and transferred from soil layers to the karst matrix, where some nitrate was retained and denitrified. Nitrate isotopic composition changed rapidly during the rising limb of events and slowly during the falling limb. The main nitrate source was synthetic fertiliser (up to 80% during event flow), transported by conduit flow following high rainfall events, and this contribution increased significantly as discharge increased. Soil organic nitrogen contribution remained constant indicating at baseflow this is the primary source. Isotope source appointment of nitrate export revealed that synthetic fertilizer accounted for more than half of the total nitrate export, which is double that of the secondary source (soil organic nitrogen), providing valuable information to inform catchment management to reduce nitrate losses and fluvial loading. Careful land management and fertilizer use are necessary to avoid nitrate pollution in the karst agroecosystem, for example by timing fertilizer applications to allow for plant uptake of nitrate before rainfall can flush it from the soils into the karst and ultimately into catchment drainage.
DOI Link: 10.1016/j.watres.2020.116388
Rights: This is an open access article distributed under the terms of the Creative Commons CC-BY license (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. You are not required to obtain permission to reuse this article.
Licence URL(s): http://creativecommons.org/licenses/by/4.0/

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