Characterisation of agricultural drainage ditch sediments along the phosphorus transfer continuum in two contrasting headwater catchments

Shore, Mairead and Jordan, Phil and Mellander, Per-Erik and Kelly-Quinn, Mary and Daly, Karen and Sims, James Tom and Wall, David P. and Melland, Alice Rowena (2016) Characterisation of agricultural drainage ditch sediments along the phosphorus transfer continuum in two contrasting headwater catchments. Journal of Soils and Sediments, 16 (5). pp. 1643-1654. ISSN 1439-0108

Abstract

Purpose: This study investigated the phosphorus (P) source, mobilisation and transport potential of ditch bed sediments as well as surrounding field and bank soils in two agricultural headwater catchments with contrasting soil drainage capacities. This information is important for discerning the potential for ditches to attenuate or augment transfers of P from upstream sources and thus for developing appropriate management strategies for these features. Materials and methods: Phosphorus sources were characterised using the Mehlich3-P, water-soluble P and total P tests. Phosphorus mobilisation potential was characterised using the Mehlich3-AL/P, Mehlich3-Ca/P and DESPRAL P tests. Phosphorus transport potential was characterised using data collected on the presence/absence of surface water in ditches during field surveys and downstream turbidity data. Results and discussion: Ditch sediments had similar P source contents (Mehlich3-P, water-soluble P and total P) to the surrounding field soils and higher P contents than bank soils. However, calcium contents of sediments in the poorly drained catchment reflected the deep sub-soils rather than the surrounding field and bank soils. Mehlich3-Al/P and Mehlich3-Ca/P contents of ditch sediments in the well (non-calcareous) and poorly (calcareous) drained catchments respectively indicated potential for P retention (above thresholds of 11.7 and 74, respectively). However, sediments were less aggregated than field soils and may mobilise more particulate P (PP) during rain events. Nevertheless, the majority of surveyed ditches dried out from March to September 2011; thus, their potential to mobilise PP may be less important than their capacity to attenuate soluble and PP during this time. Conclusions: In these and similar catchments, soluble P attenuation and particulate P mobilisation should be maximised and minimised, respectively, for example, by cleaning out the sediments before they become saturated with P and encouraging vegetation growth on ditch beds. This study also highlighted the influence of deep sub-soils on soluble P retention in ditches and thus the utility of characterising soils below depths normally included in soil classifications.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Published version cannot be displayed due to copyright restrictions.
Faculty / Department / School: Current - Institute for Agriculture and the Environment
Date Deposited: 06 Mar 2017 05:23
Last Modified: 06 Mar 2017 05:49
Uncontrolled Keywords: attenuation, drainage ditches, mobilisation, phosphorus, sediment
Fields of Research : 07 Agricultural and Veterinary Sciences > 0799 Other Agricultural and Veterinary Sciences > 079901 Agricultural Hydrology (Drainage, Flooding, Irrigation, Quality, etc.)
07 Agricultural and Veterinary Sciences > 0701 Agriculture, Land and Farm Management > 070101 Agricultural Land Management
05 Environmental Sciences > 0502 Environmental Science and Management > 050206 Environmental Monitoring
Socio-Economic Objective: D Environment > 96 Environment > 9609 Land and Water Management > 960905 Farmland, Arable Cropland and Permanent Cropland Water Management
D Environment > 96 Environment > 9614 Soils > 961402 Farmland, Arable Cropland and Permanent Cropland Soils
D Environment > 96 Environment > 9606 Environmental and Natural Resource Evaluation > 960608 Rural Water Evaluation (incl. Water Quality)
Identification Number or DOI: 10.1007/s11368-015-1330-0
URI: http://eprints.usq.edu.au/id/eprint/30879

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