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Identifying contrasting influences and surface water signals for specific groundwater phosphorus vulnerability

Mellander, P.-E., Jordan, P., Shore, M., McDonald, N.T., Wall, D.P., Shortle, G. and Daly, K. (2015) Identifying contrasting influences and surface water signals for specific groundwater phosphorus vulnerability. Science of The Total Environment, 541 . 292 - 302. [Journal article]

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URL: http://www.sciencedirect.com/science/article/pii/S0048969715307427

DOI: 10.1016/j.scitotenv.2015.09.082

Abstract

Two groundwater dominated catchments with contrasting land use (Grassland and Arable) and soil chemistry were investigated for influences on P transfer below the rooting zone, via the aquifer and into the rivers. The objective was to improve the understanding of hydrochemical process for best management practise and determine the importance of P transfer via groundwater pathways. Despite the catchments having similar inorganic P reserves, the iron-rich soils of the Grassland catchment favoured P mobilisation into soluble form and transfer to groundwater. Sites in that catchment had elevated dissolved reactive P concentrations in groundwater (>0.035 mg/l) and the river had flow-weighted mean TRP concentrations almost three times that of the aluminium-rich Arable catchment (0.067 mg/l compared to 0.023 mg/l). While the average annual TRP flux was low in both catchments (although three times higher in the Grassland catchment; 0.385 kg/ha compared to 0.128 kg/ha), 50% and 59% of TRP was lost via groundwater, respectively, during winter periods that were closed for fertiliser application. For policy reviews, slow-flow pathways and associated time-lags between fertiliser application, mobilisation of soil P reserves and delivery to the river should be carefully considered when reviewing mitigating strategies and efficacy of mitigating measures in groundwater fed catchments. For example, while the Grassland catchment indicated a soil-P chemistry susceptibility, the Arable catchment indicated a transient point source control; both resulted in sustained or transient periods of elevated low river-flow P concentrations, respectively.

Item Type:Journal article
Keywords:Eutrophication, phosphorus, groundwater, catchments, agriculture
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:32380
Deposited By: Professor Phil Jordan
Deposited On:30 Sep 2015 12:15
Last Modified:17 Oct 2017 16:19

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