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Updating the User Manual (2) Mitigation Options for Sediment and Phosphorus 2 (MOPS 2) - WQ0127

The UK is committed to improving water quality. The EU Water Framework Directive includes specific requirements to control diffuse pollution (DP) and also places requirements on national governments to set water quality objectives based on biodiversity and good ecological status. The EU Habitats Directive and the UK government’s Quality of Life indicators set targets for achieving favourable conditions on conservation sites, the UK Biodiversity Action Plan aims to reverse decline and restore populations for key species. Phosphorus (P), nitrogen (N) and sediment play a pivotal role in influencing water quality and biodiversity, and agriculture is thought to be responsible for 30% of the inputs of P inputs to surface waters [1]. Sediment eroded from the soil is a pollutant in its own right: reducing light penetration and physically damaging freshwater ecosystems, sediments also carry pollutants such as pesticides, pathogens and metals [2-4]. Phosphorus is of particular interest because of its low solubility and as it is associated primarily with the finer fractions of the soil [3, 5]. Fine sediments are easily transported to surface waters where the P may later be released [6]. Studies commissioned by the Environment Agency [7, 8] indicate that P concentrations need to be one order of magnitude lower in fresh water to avoid the biodiversity impact designated in the EU Water Framework Directive. There is therefore an urgent need for mitigation measures to tackle diffuse source pollution from agriculture.

Recently, Defra has commissioned projects to draw together the available knowledge on practical measures to control sediment and P loss from agricultural fields (PE0203; ES0203; ES0121). These are presented in an inventory of methods to control diffuse water pollution from agriculture (DPI Manual) [11]. The DPI Manual lists 44 measures, 24 of which are directly applicable to arable agriculture. It also identifies the effectiveness of each of the measures. However there is limited information to support the effectiveness of the methods, and for many of the mitigation measures the authors have had to rely on expert judgement due a lack of quantification of their performance. This lack of evidence reflects the fact that there have been relatively few trials of mitigation options in the UK, which means there remains considerable uncertainty over whether measures actually work in practice in the UK and how their effectiveness is mediated by factors including landscape placement, previous crop, and soil conditions. Notable exceptions include the Mitigation Options for Phosphorus and Sediment project (MOPS PE0206), the Woburn Erosion Reference Experiment [12-14], the MAFF Buffer Zones in Headwater Catchments project (CSA2285) [15], the Buffers project (PE0205), and Erosion Control in Maize Fields (SP0404). Other work on the use of minimum tillage to control erosion and diffuse pollution has been carried out by the Environment Agency and has been the focus of the EU-LIFE SOWAP (Soil and Surface Water Protection using Conservation Tillage in Northern and Central Europe) project. These trials have demonstrated the potential for using mitigation measures to control sediment and associated nutrient losses from agriculture, and some of the potential pitfalls. (A detailed review of the evidence for the effectiveness of mitigation measures in combinable copping systems has been developed under the MOPS project, and a second review detailing the likely consequences for pollution swapping has also been produced by the MOPS project [16]). Together with the DPI Manual, results from these projects have helped and are helping to inform the ‘Whole Farm Approach’ currently being promoted by Defra, revisions being made to Environmental Stewardship, and the Conservative Party’s ‘Blueprint for a green economy’ policy document. Advice to farmers on DP control will also be available through the revised Code of Good Agricultural Practice.

Research undertaken by the same consortium in the precurosr project MOPS 1 (Defra project PE0206) developed and tested the cost-effectiveness of practical options for mitigating sediment and phosphorus loss from autumn-sown combinable cropping systems. MOPS 1 provided evidence concerning the effectiveness of minimum tillage, contour cultivation, in-field grass barriers, residue management and the disruption of tramlines (tractor tyre tracks), both scientifically and economically [17-20].

In this proposal we address two other areas of arable agriculture which have received limited attention:
(i) losses of sediment and phosphorus from spring-sown crops (such as potatoes), and the cost-effectiveness of different measures for mitigating these losses, and
(ii) the role of subsurface pathways and on-farm retention ponds as potential mechanisms to limit sediment and nutrient losses from farm landscapes into the main river system.
1. To review critically the use of ponds and wetlands for controlling diffuse pollution.
2. To establish the effectiveness of ponds and wetlands for the control of diffuse pollution in the arable landscape of England and Wales.
3. To make recommendations to Defra on the use and design of ponds and wetlands for diffuse pollution control in the arable landscape of England and Wales.
4. To review critically the literature on the control of diffuse pollution from spring-sown crops.
5. To provide evidence on the effectiveness of diffuse pollution control measures in spring-sown crops, particularly potatoes.
6. To make recommendations to Defra on mitigating diffuse pollution from spring-sown crops.
7. To determine the cost-effectiveness of the mitigation measures assessed in [2] and [5] above under a variety of management situations (and in a form suitable for updating Defra’s Diffuse Pollution inventory manual).
8. To assess the potential for uptake of the mitigation measures developed under precursor Defra project PE0206 (MOPS 1) and from objectives 2 and 5 above.
Project Documents
• FRP - Final Report : WQ0127 MOPS2 Final report   (2478k)
• ANX - Annex : WQ0127 MOPS2 Appendix 1 Ponds Site plans   (850k)
• ANX - Annex : WQ0127 MOPS2 Appendix 2 Ponds Methodology   (149k)
• ANX - Annex : WQ0127 MOPS2 Appendix 3 Ponds Supp Results   (1524k)
• ANX - Annex : WQ0127 MOPS2 Appendix 4 Ponds addiitonal KE   (105k)
• ANX - Annex : WQ0127 MOPS2 Appendix 6 Potatoes KE   (63k)
• ANX - Annex : WQ0127 MOPS2 Appendix 7 CostEffectiveness   (179k)
• ANX - Annex : WQ0127 MOPS2 Appendix 7 CostEffectiveness   (179k)
• ANX - Annex : WQ0127 MOPS2 Appendix5.1 Wetlands Leaflet   (2028k)
• ANX - Annex : WQ0127 MOPS2 Appendix5.2 Wetland Construction   (382k)
• ANX - Annex : WQ0127 MOPS2 Appendix5.3 Policy Briefing Document   (987k)
Time-Scale and Cost
From: 2008

To: 2013

Cost: £1,355,263
Contractor / Funded Organisations
University - Lancaster, ADAS UK Ltd.
Agriculture and Water Quality              
Diffuse Pollution              
Sustainable Farming and Food Science              
Water Quality              
Water Quality and Use