Impacts of different vegetation in riparian buffer strips on hydrology and water quality

This project will investigate the impacts of different vegetation in buffer strips on runoff and pollution loss from agricultural land. Runoff from agricultural land and the pollution it carries continue to cause problems for flooding and water quality. The impacts of flooding arising from runoff from farmed land have been well documented in recent times, including during the wet winter of 2013 - e.g. on the Somerset Levels. Many of our rivers experience water quality problems which have implications for freshwater biology and water treatment costs. Better controls are therefore required in the context of the need for sustainable intensification of our farming. Buffer strips continue to feature in current revisions to agri-environment policy for helping deliver sustainable farming. These revisions affect subsidies for farmers in the form of 'greening' options and funding as part of the new Countryside Stewardship scheme (which commences in January 2016). Despite the continued inclusion of buffers as a 'catch-all' on-farm control option to combat diffuse runoff problems contributing to flooding and, pollution contributing to failure of water quality targets, evidence on the costs and effectiveness of different vegetation types is limited. This project will therefore use an established experimental facility to test deep-rooting grass, deciduous woodland and willow bioenergy crop covers in buffers for reducing runoff and losses of nutrients, sediment and pesticides. The buffers will be tested for reducing runoff and water pollution from grass and maize during a five year study. To expand beyond the experimental site, the new data on the costs and effectiveness of the different vegetation covers will be scaled up to examine potential economic benefits across England and Wales. A clear understanding of costs and benefits is important for industry to engage with research outputs and to encourage on-the-ground delivery of tested measures for farmers. Engagement with industry will be enhanced through demonstration of the plots to stakeholder groups. The project team brings a strong track record of buffer research and well-developed links to stakeholder networks including the grass, woodland and willow industries and those associated with on-going research platforms such as the Defra Demonstration Test Catchment (DTC) and Sustainable Intensification Platform (SIP) programmes, as well as the BBSRC funded North Wyke Farm Platform national capability.

Buffer strips continue to be included as a 'catch-all' on-farm mitigation option to combat pollutant emissions contributing to failure of water quality targets and diffuse runoff problems contributing to flooding, but, evidence on the cost-effectiveness and cost-benefit of different vegetation types is limited. This project will use replicated plot experiments (n=3 per treatment) to test novel grass (Festulolium loliaceum cv Prior), deciduous woodland and willow bioenergy crops in buffers for reducing runoff and losses of nutrients, sediment and pesticides, using comparison with replicated controls (n=3). Samples of nutrients and sediment will be collected using flow-proportional sampling with autosamplers. Sampling for pesticides will be time-integrated using passive devices routinely deployed by water companies. New empirical data on the efficacy and costs of the buffer treatments for runoff and pollutant reduction at plot scale will be scaled up using a national modelling framework to explore strategic economic benefits for England and Wales. Industrial engagement will be enhanced through demonstration of the plots to stakeholder groups. Scenario modelling will place spatially targeted application of the buffer treatments in the context of the evolution of agri-environment policy under CAP reform 2014-2020. The project team brings a strong track record of buffer research and well-developed links to stakeholder networks including the grass, woodland and willow industries and those associated with the Defra Demonstration Test Catchment and Sustainable Intensification platforms. . The outcome of the work will contribute new scientific knowledge with respect to the nutrient, sediment and pesticide trapping efficacy of these vegetation types, economic assessment of different potential crops in buffers strips, as well as help develop protocols and guidelines that simplify key messages for buffer strip vegetation management options.

The findings will deliver both socio-economic and academic impacts. Socio-economic impacts will include a contribution to evidence-based policy-making by Defra for water pollution and flooding control at national, regional and local levels. Riparian buffers continue to feature strongly in ongoing revisions to agri-environment policy embodied in current changes to both European Union (EU) Pillar I (Cross Compliance) and Pillar II (stewardship schemes) funding for on-farm interventions for minimising environmental problems.
New empirical evidence on the cost-effectiveness of buffers with different vegetation types will thereby contribute to environmental protection, sustainability and impact reduction (the potentially negative impact of farming on water quality and flooding). The new empirical evidence on the costs and efficacy of the different buffer vegetation types will deliver improved knowledge to the national agri-advice community in the UK, including as examples, farm advisors (e.g. independent or company agronomists for the livestock and arable sectors), Catchment Officers (e.g. in the Catchment Sensitive Farming programme; CSF), NGOs delivering on-farm advice (e.g. the Rivers Trust), levy board staff (AHDB), as well as personnel in the bodies responsible for the protection of natural resources (e.g. Environment Agency, Natural England, Forestry Commission, Chemical Regulations Directorate). The new empirical evidence will provide a basis for updating dictionaries of best management practice for agriculture, including the widely used Defra User Guide for on-farm interventions for pollution control. It will also contribute to the strategic price reviews for OFWAT undertaken by water companies by contributing evidence on the cost-benefit of differently vegetated buffers as soft engineering measures for helping to deliver drinking water quality targets set by the Drinking Water Inspectorate (DWI) of England and Wales. The modelled data generated by the upscaling component will contribute to strategic scale economic analyses undertaken by the Environment Agency and Defra in response to reporting commitments for the EU Water Framework Directive.
It is envisaged that the pathway to socio-economic impact will be strongly supported by using the links between the investigators and current ongoing major long-term industry-focussed platforms for science-based agri-environment policy support; the Defra Demonstration Test Catchment (DTC) and Sustainable Intensification Platform (SIP) programmes. Each of these programmes has well-developed local and national stakeholder networks including farmers, environmental bodies, NGOs, water companies, local government and policy teams.
A range of academic impacts will be delivered. These will include the training of the researcher in transferable sampling, monitoring, analytical and reporting skills, contributions to international scientific conferences (e.g. European Geophysical Union - EGU, American Geophysical Union - AGU, Land Use and Water Quality - LUWQ) and the production of high impact scientific journal papers summarising the findings. The PI will be President of an international commission of the International Association of Hydrological Sciences (IAHS) during the project and this will provide an opportunity to disseminate the findings at international conferences supported by IAHS (e.g. International Union of Geodesy and Geophysics - IUGG). The results of the experimental work for the novel grass buffers will provide additional scientific evidence on this treatment in support of the ongoing North Wyke Farm Platform national capability funded by BBSRC.