Modification of exploration of long‐term nutrient trajectories for nitrogen (ELEMeNT-N) model to quantify legacy nitrogen dynamics in a typical watershed of eastern China
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Published:2023-05-12
Issue:6
Volume:18
Page:064005
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ISSN:1748-9326
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Container-title:Environmental Research Letters
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language:
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Short-container-title:Environ. Res. Lett.
Author:
Zhou Jia,Wei Yinghuai,Wu Kaibin,Wu Hao,Jiao Xinyi,Hu Mingpeng,Chen Dingjiang
Abstract
Abstract
Legacy nitrogen (N) is recognized as a primary cause for the apparent failure of watershed N management strategies to achieve desired water quality goals. The ELEMeNT-N (exploration of long‐term nutrient trajectories for nitrogen) model, a parsimonious and process-based model, has the potential to effectively distinguish biogeochemical and hydrological legacy effects. However, ELEMeNT-N is limited in its ability to address long-term legacy N dynamics as it ignores temporal changes in soil organic N (SON) mineralization rates. This work represents the first use and modification of ELEMeNT-N to quantify legacy effects and capture spatial heterogeneity of legacy N accumulation in China. An exponential function based on mean annual temperature was employed to estimate yearly changes in SON mineralization rate. Based on a 31 year water quality record (1980–2010), the modified model achieved higher efficiency metrics for riverine N flux in the Yongan watershed in eastern China than the original model (Nash–Sutcliff coefficient: 0.87 vs. 0.72 and R
2: 0.80 vs. 0.71). The modified ELEMeNT-N results suggested that the riverine N flux mainly originated from the legacy N pool (88.2%). The mean overall N lag time was 11.9 years (95% confidence intervals (CIs): 8.3–21.3), of which biogeochemical lag time was 9.7 years (6.3–18.4) and hydrological lag time was 2.2 years (2.0–3.0). Legacy N accumulation showed considerable spatial heterogeneity, with 219–239 kg N ha−1 accumulated in soil and 143–188 kg N ha−1 accumulated in groundwater. The ELEMeNT-N model was an effective tool for addressing legacy N dynamics, and the modified form proposed here enhanced its ability to capture SON mineralization dynamics, thereby providing managers with critical information to optimize watershed N pollution control strategies.
Funder
National Natural Science Foundation of China
National Key Research and Development Program of China
Subject
Public Health, Environmental and Occupational Health,General Environmental Science,Renewable Energy, Sustainability and the Environment
Cited by
1 articles.
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