Defra - Department for Environment, Food and Rural Affairs.

Science Search

Science and Research Projects

Return to Science Search homepage   Return to Project List

Identification of high risk soils for sediment-associated P loss in subsurface flow and an assessment of its - NT1025

Description
Title continuation: contribution to catchment sediment budgets

The overall aim of this study will be to obtain an improved understanding of the sediment budgets of agricultural catchments and their influence on P losses from such catchments, with particular attention given to identifying the source of particulate P lost from agricultural soils in drainflow. For the 2 catchments to be studied (Trent and Rosemaund catchments), sediment budgets will be developed and suitable mixing models evaluated to describe sediment loss for small agricultural catchments. The contribution of stream bank erosion to sediment will be estimated using channel resurveys and erosion pin measurements. For each catchment, a reconnaissance survey will identify dominant land use and soil types. Within each land use and soil type, soil cores will be retrieved in order to: characterise the mineral magnetic properties of source materials on a bulk and particle size specific basis; characterise the radionuclide signatures of the source materials; characterise the geochemical signatures of the source materials; and identify the total P concentration and P speciation of source materials. Large volume samples will be collected during storm runoff events from monitored tile drains, subcatchment(s) and catchment outlet. These will provide sufficient sediment (separated using a field portable Alfa-Laval high speed liquid centrifuge) for measurement of radionuclide, mineral magnetic and geochemical signatures. Field erosion rates will be determined by multiple coring of soil profiles within selected fields. These cores will be analysed for their Cs-137 inventories from which an assessment will be made of both total solid loss from the field and areas of soil accumulation and loss within the field. A GIS system will be developed for predicting high risk areas for particulate P loss and the route by which it is transported; this GIS system will also be used to provide a basis for developing risk management strategies to control particulate P loss. Results of the study will be used to develop guidelines for loss reduction strategies for particulate P relevant to different risk areas in the UK as identified by the model. A final report to MAFF and at least one refereed scientific paper will be produced.
Project Documents
• Final Report : Identification of high risk soils for sediment-associated P loss in subsurface flow and an assessment of its contribution to catchment sediment budgets   (4088k)
Time-Scale and Cost
From: 1997

To: 2000

Cost: £319,214
Contractor / Funded Organisations
University - Coventry, ADAS UK Ltd., University - Exeter
Keywords
              
Fields of Study
Fertilisers and Nitrate Pollution