‘Manure trading’: a novel socio-economic lever to promote effective diffuse pollution management in agricultural catchments?


Although land and water are intricately linked, not all land is equal in contributing towards impacts on water quality. Heterogeneities in the landscape (e.g. soil type, land-use), coupled with variable approaches to how land is managed, result in a varied patchwork of farmed fields – some highly productive, others heavily modified, some more risky in terms of pollutant loss. Recognising spatial sensitivity in land vulnerability for contributing to diffuse pollution is clearly an important first step in the design of mitigation and management options for protecting water quality. However, the next challenge is to implement spatial targeting of management options in the ‘right place’ and at the ‘right time’, and to influence on-farm decision-making for areas of land where it will have the highest impact and the most benefit for wider environmental water quality. Therefore, the aim of this studentship is to investigate a new dimension in diffuse pollution management for the protection of raw water quality. The project will explore how the catchment export of manure-derived pollutants can respond to novel social & economic influences on manure management and land use. By using a combination of environmental economics and diffuse pollution modelling, the student will develop an approach centred on the concept of ‘manure trading’. This novel management strategy will complement existing catchment sensitive farming agendas, and provide the socio-economic incentive needed to improve water quality in catchment systems.

Livestock manure trading has been used cost-effectively to recycle nutrients within the landscape and improve soil fertility in several countries, including the Netherlands, Belgium, France and the USA. In the UK, Nitrate Vulnerable Zone guidelines have also encouraged farmers to trade surplus animal manure, although this has been met with limited success. However, there is evidence that some farmers do voluntarily engage in such trades because they are economically mutually beneficial. This studentship will use a range of catchments to further develop the concept of manure trading, and by using recent advances in hydrological connectivity and spatial risk mapping, this project will adjust and fine-tune such trading to benefit the water environment.

Many jurisdictions mandate how livestock manures are managed to protect adjacent water quality from microbial pollutants and nutrients that pose an environmental and human health risk. Current limits however, are not catchment, farm or subfield specific enough, i.e. they do not reflect the inherent spatial variation in diffuse pollution risk at a fine spatial resolution. More importantly, they do not account for the hydrological connectivity or landscape flow pathways of faecal bacteria, phosphorus and nitrogen from manure applications across the landscape. Significant advances in surveillance science have made it feasible to identify high & low risk areas of land in terms of pollutants from manure, which could provide a greater incentive for trading this valuable resource.

Key research questions: This studentship will develop the novel socio-economic tool of ‘manure-trading’ as a method to reduce multi-pollutant (nutrient and pathogen) loading pressures on land considered being most at risk of generating diffuse pollution. This approach will be developed and tested with a view to become an additional component of a wider catchment management toolbox for water quality protection. Project objectives include:

O1. Develop a conceptual model to inform on the spatial & temporal scenarios that govern where and when the cost-effectiveness of strategies for managing raw water quality via manure management & trading may exceed that of strategies designed to target water treatment;

O2. Co-construct a socio-economic framework with relevant stakeholders to legitimise the concept of ‘manure-trading’ as an approach to influence decision making for water quality benefits in catchments;

O3. Undertake a comprehensive survey to understand wider stakeholder perceptions surrounding the use of incentive schemes to reduce diffuse pollution and evaluate responses to the concept of manure-trading & the socio-economic framework thus far developed;

O4. Devise and run a series of manure-trading choice experiments in priority case study catchments with farmer & advisor communities to test the potential of manure-trading as a viable socio-economic lever to aid water quality management.


This interdisciplinary project will link catchment science, environmental modelling and socio-economics. The student will explore the role of different diffuse pollution modelling tools that help to identify and prioritise land in terms of its riskiness. A number of contrasting case study catchments will be selected to provide variation in terms of the importance of different manure-derived contaminants of concern. Differences in in perception, participation and attitudes towards manure-trading and water pollution across different stakeholder groupings will be explored. It is hypothesised that the associated risk perceptions, end-user acceptability & likelihood of uptake of manure-trading will differ between stakeholder & end-user groups. To test this hypothesis the student will use a combination of surveys and experiments to obtain directly comparable perceived risk and acceptability scores from key stakeholders across a range of priority catchments. The student will undertake choice experiments of catchment farmers to identify their willingness to participate in manure trading and spatially targeted risk-based applications to their land. The choice experiment surveys will enable the student to quantify farmer’s willingness to pay/accept to buy/sell animal waste as well as infer their preferences for the attributes associated with any regulatory inspection regime that accompanies such trading. The studentship will culminate in an evaluation of manure-trading options across different categories of landscape risk to identify: (i) win-win opportunities for farm businesses and water quality; (ii) potential for pollution swapping associated with manure trading schemes; (iii) added benefits versus potential trade-offs that may emerge from the use of manure-trading as an incentive alongside other voluntary and regulatory schemes designed to protect water quality; and (iv) possible negative impacts on farm business units from partaking in such a scheme.

Project Timeline

Year 1

Critical review of the literature (months: 0-4), diffuse pollution modelling (SCIMAP) & liaison with relevant stakeholders to determine the patterns of nutrient loss risk across priority catchments & develop conceptual model (months 4-12);

Year 2

Develop a socio-economic framework to investigate the economic feasibility (& economic benefit) of creating a catchment-based manure market aligned with catchment diffuse pollution risks (months 12-22);

Year 3

In-field choice experiments and catchment surveys of attitudes and perceptions towards manure-trading (months 23-36);

Year 3.5

Writing up (months 36-42)

& Skills

This studentship will combine risk assessment with risk communication, centred on the topic of water quality protection & environmental economics. It will provide a platform to build an interdisciplinary research career in the context of integrated catchment management. The studentship will broaden the scope of the applicant’s skills base by providing specialist training in the use of diffuse pollution modelling, including participatory approaches to modelling, and by developing expertise in interdisciplinary skills associated with stakeholder engagement techniques and methodologies for choice-based experiments.

References & further reading

Useful further reading:

Aftab, A., Hanley, N. and Baiocchi, G., 2017. Transferability of policies to control agricultural nonpoint pollution in relatively similar catchments. Ecological Economics, 134, pp.11-21.

Reaney, S.M., Mackay, E.B., Haygarth, P.M., Fisher, M., Molineux, A., Potts, M. and Benskin, C.M.H., 2019. Identifying critical source areas using multiple methods for effective diffuse pollution mitigation. Journal of environmental management, 250, p.109366.

Stosch KC, Quilliam RS, Bunnefeld N & Oliver DM (2019). Quantifying stakeholder understanding of an ecosystem service trade-off, Science of the Total Environment, 651, 2524-2534.

Further Information

For informal enquires: Dr David Oliver (david.oliver@stir.ac.uk tel: 01786 467846)

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