Evaluating the critical source area concept of phosphorus loss from soils to water-bodies in agricultural catchments

Shore, M. and Jordan, P. and Mellander, P. -E. and Kelly-Quinn, M. and Wall, D. P. and Murphy, P. N. C. and Melland, A. R. (2014) Evaluating the critical source area concept of phosphorus loss from soils to water-bodies in agricultural catchments. Science of the Total Environment, 490. pp. 405-415. ISSN 0048-9697


Using data collected from six basins located across two hydrologically contrasting agricultural catchments, this study investigated whether transport metrics alone provide better estimates of storm phosphorus (P) loss from basins than critical source area (CSA) metrics which combine source factors as well. Concentrations and loads of P in quickflow (QF) were measured at basin outlets during four storm events and were compared with dynamic (QF magnitude) and static (extent of highly-connected, poorly-drained soils) transport metrics and a CSA metric (extent of highly-connected, poorly-drained soils with excess plant-available P).Pairwise comparisons between basins with similar CSA risks but contrasting QF magnitudes showed that QF flow-weighted mean TRP (total molybdate-reactive P) concentrations and loads were frequently (at least 11 of 14 comparisons) more than 40% higher in basins with the highest QF magnitudes. Furthermore, static transport metrics reliably discerned relative QF magnitudes. However, particulate P (PP) concentrations were often (6 of 14 comparisons) higher in basins with the lowest QF magnitudes, most likely due to soil-management activities (e.g. ploughing), in these predominantly arable basins at these times. Pairwise comparisons between basins with contrasting CSA risks and similar QF magnitudes showed that TRP and PP concentrations and loads did not reflect trends in CSA risk or QF magnitude. Static transport metrics did not discern relative QF magnitudes between these basins.In basins with contrasting transport risks, storm TRP concentrations and loads were well differentiated by dynamic or static transport metrics alone, regardless of differences in soil P. In basins with similar transport risks, dynamic transport metrics and P source information additional to soil P may be required to predict relative storm TRP concentrations and loads. Regardless of differences in transport risk, information on land use and management, may be required to predict relative differences in storm PP concentrations between these agricultural basins.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © 2014 Elsevier B.V. Permanent restricted access to published version in accordance with the copyright policy of the publisher.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Agricultural, Computational and Environmental Sciences
Date Deposited: 30 Jun 2014 01:04
Last Modified: 04 Jul 2016 05:18
Uncontrolled Keywords: basin; critical source area; hydrology; quickflow; soil; transport risk
Fields of Research : 03 Chemical Sciences > 0306 Physical Chemistry (incl. Structural) > 030607 Transport Properties and Non-equilibrium Processes
05 Environmental Sciences > 0503 Soil Sciences > 050305 Soil Physics
07 Agricultural and Veterinary Sciences > 0701 Agriculture, Land and Farm Management > 070101 Agricultural Land Management
Socio-Economic Objective: D Environment > 96 Environment > 9614 Soils > 961499 Soils not elsewhere classified
Identification Number or DOI: 10.1016/j.scitotenv.2014.04.122
URI: http://eprints.usq.edu.au/id/eprint/25387

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