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The role of mobilisation and delivery processes on contrasting dissolved nitrogen and phosphorus exports in groundwater fed catchments

Dupas, R., Mellander, P.-E., Gascuel-Odoux, C., Fovet, O., McAleer, E.B., McDonald, N.T., Shore, M. and Jordan, P. (2017) The role of mobilisation and delivery processes on contrasting dissolved nitrogen and phosphorus exports in groundwater fed catchments. Science of The Total Environment, 599600 . 1275 - 1287. [Journal article]

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URL: http://www.sciencedirect.com/science/article/pii/S0048969717311919

DOI: https://doi.org/10.1016/j.scitotenv.2017.05.091

Abstract

Abstract Diffuse transfer of nitrogen (N) and phosphorus (P) in agricultural catchments is controlled by the mobilisation of sources and their delivery to receiving waters. While plot scale experiments have focused on mobilisation processes, many catchment scale studies have hitherto concentrated on the controls of dominant flow pathways on nutrient delivery. To place mobilisation and delivery at a catchment scale, this study investigated their relative influence on contrasting nitrate-N and soluble P concentrations and N:P ratios in two shallow groundwater fed catchments with different land use (grassland and arable) on the Atlantic seaboard of Europe. Detailed datasets of N and P inputs, concentrations in shallow groundwater and concentrations in receiving streams were analysed over a five year period (October 2010-September 2015). Results showed that nitrate-N and soluble P concentrations in shallow groundwater give a good indication of stream concentrations, which suggests a dominant control of mobilisation processes on stream exports. Near-stream attenuation of nitrate-N (- 30%), likely through denitrification and dilution, and enrichment in soluble P (+ 100), through soil-groundwater interactions, were similar in both catchments. The soil, climate and land use controls on mobilisation were also investigated. Results showed that grassland tended to limit nitrate-N leaching as compared to arable land, but grassland could also contribute to increased P solubilisation. In the context of land use change in these groundwater fed systems, the risk of pollution swapping between N and P must be carefully considered, particularly for interactions of land use with soil chemistry and climate.

Item Type:Journal article
Keywords:Agricultural catchment Land use Climate Nutrients Nitrate Phosphorus
Faculties and Schools:Faculty of Life and Health Sciences > School of Geography and Environmental Sciences
Faculty of Life and Health Sciences
Research Institutes and Groups:Environmental Sciences Research Institute
Environmental Sciences Research Institute > Freshwater Sciences
ID Code:37931
Deposited By: Professor Phil Jordan
Deposited On:20 May 2017 20:31
Last Modified:17 Oct 2017 16:29

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