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Dissolved organic carbon and dissolved oxygen determine the nitrogen removal rate constant in small water bodies of intensive agricultural region.
- Source :
-
Agriculture, Ecosystems & Environment . Feb2024, Vol. 361, pN.PAG-N.PAG. 1p. - Publication Year :
- 2024
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Abstract
- Small water bodies are extensively distributed and play critical roles in nitrogen (N) removal, primarily through sediment denitrification. However, our comprehension understanding of the N removal rate constant in these systems, particularly within the first-order kinetics model, remains limited. To address this gap, a one-year field study was conducted to investigate the N removal rate and N removal rate constant in various small water bodies within a typical intensive agricultural area. We observed a decrease in N removal rates in the downstream direction, from ditches to downstream ponds and streams, potentially due to upstream water bodies receiving higher nutrient inputs. Moreover, our findings revealed that the N removal process in small water bodies generally follows a first-order kinetics reaction model, with the N removal rate constant varying from 0.22 d 1 in streams and 0.48 d 1 in vegetated ditches. Both water dissolved organic carbon (DOC) and dissolved oxygen (DO) concentrations collectively influenced the N removal rate constants. By leveraging the relationship between the N removal rate constant and these environmental factors, we further estimated that, on average, small water bodies remove 68% of the N loading in the Dongting Lake Basin. We recommend implementing artificial management measures, such as vegetation, to enhance the N removal capacity of water bodies. However, the caution must be exercised in measures like concrete linings in ditches, as they can hinder N removal. These findings not only offer methods for estimating N removal in small water bodies, but also provide an insight into enhancing the N removal capacity of these systems to effectively mitigate non-point N pollution. [Display omitted] • Small water bodies in our intensive agricultural areas remove 68% of the N loading. • N removal rates decrease along the flow direction in small water bodies. • Both dissolved organic carbon and dissolved oxygen determine N removal rate constants. • Vegetation enhances N removal capacity, while concrete linings hinder it. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 01678809
- Volume :
- 361
- Database :
- Academic Search Index
- Journal :
- Agriculture, Ecosystems & Environment
- Publication Type :
- Academic Journal
- Accession number :
- 174013612
- Full Text :
- https://doi.org/10.1016/j.agee.2023.108822