Quantifying nutrient transfer pathways in agricultural catchments using high temporal resolution data

Mellander, Per-Erik and Melland, Alice R. and Jordan, Phil and Wall, David P. and Murphy, Paul N. C. and Shortle, Ger (2012) Quantifying nutrient transfer pathways in agricultural catchments using high temporal resolution data. Environmental Science and Policy, 24. pp. 44-57. ISSN 1462-9011

Abstract

There are uncertainties in the definition of phosphorus (P) and nitrogen (N) transfer pathways within agricultural river catchments due to spatiotemporal variations such as water recharge and the farming calendar, or catchment soil and hydrogeological properties. This can have implications for mitigation policies. This study combined detailed pathway studies with catchment integrated studies to characterise N and P transfer pathways for four agricultural catchments with different land management, soil drainage and geology. A Loadograph Recession Analysis (LRA) method is introduced, to identify and quantify integrated delivery transfer pathways of total oxidised nitrogen (TON), total reactive phosphorus (TRP) and total phosphorus (TP). High temporal resolution river discharge and water quality measurements from a large runoff event (and recession) were used. In two catchments with well drained soils, below-ground delivery pathways of TON represented up to 97% of the total flow event load, and up to 63% of the TRP and TP load. In these catchments, hydrological quick flow pathways were only 2-8% of total flow but were efficient in delivering P (up to 50%). Two other catchments had poor to moderately drained soils where up to 55% of the hydrological pathways were quick flow. This quick flow delivered up to 88% of the event flow P load but background groundwater flows were apparently mixed with point source signals. Results suggest that, in catchments with permeable soils and geology, subsurface pathways will need to be considered for mitigation strategies for both diffuse N and P delivery and measures that target surface transfer pathways such as riparian buffer strips may be ineffective. In such catchments, long chemical recessions from storm events may prolong impacts on the ecological status of receiving rivers.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © 2012 Elsevier Ltd. Permanent restricted access to published version in accordance with the copyright policy of the publisher.
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Agricultural, Civil and Environmental Engineering
Date Deposited: 18 Aug 2014 02:22
Last Modified: 02 Feb 2017 05:34
Uncontrolled Keywords: baseflow; EMMA; mitigation measures; nitrogen; phosphorus; quick flow
Fields of Research : 07 Agricultural and Veterinary Sciences > 0701 Agriculture, Land and Farm Management > 070104 Agricultural Spatial Analysis and Modelling
04 Earth Sciences > 0406 Physical Geography and Environmental Geoscience > 040603 Hydrogeology
09 Engineering > 0999 Other Engineering > 099901 Agricultural Engineering
Socio-Economic Objective: D Environment > 96 Environment > 9609 Land and Water Management > 960904 Farmland, Arable Cropland and Permanent Cropland Land Management
Identification Number or DOI: 10.1016/j.envsci.2012.06.004
URI: http://eprints.usq.edu.au/id/eprint/25785

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