The role of Phosphorus in the Resilience and Sustainability of the UK food system

Phosphorus (P) is an essential nutrient required for crop and livestock production, but the global reserves of phosphate rock (PR) from which fertilisers and feeds are derived are a finite critical resource. Phosphorus cannot be made chemically and the UK has no PR reserves of its own. UK agriculture is therefore entirely dependent on P imports of fertilisers, feeds and foods, which are becoming increasingly volatile in cost. A future scarcity of P (either locally or globally), or a significant rise in the costs of P imports, therefore threaten the future security and resilience of the UK food system, but this vulnerability has not previously been evaluated. Brexit may increase the UK vulnerability to future P supply due to exclusion from EU trade agreements. The use of P within UK agriculture is also very inefficient and leads to large wastage, and loss of P to inland and coastal waters causing nutrient pollution or eutrophication. Such losses and the resulting pollution are expected to be exacerbated by climate change. Eutrophication is very costly to society and devalues many ecosystem services linked to water quality including water quantity for drinking, biodiversity and recreation. Regulatory standards to control eutrophication are based on P, and it is therefore critically important to improve the sustainability of UK farming by improving the management of P across the whole food chain. Better stewardship of P has a double benefit: it can firstly increase the resilience of the UK food system to P shocks by reducing UK reliance on P imports and secondly optimize the intensification of agriculture with minimal impact on water quality and increase the value of the ecosystem services dependent on water quality.

In this project, an interdisciplinary research team covering the biological, environmental and socio-economic sciences aims to quantify the vulnerability of UK agriculture and the UK food system to a future P scarcity and assess the thresholds at which P scarcity might impact on agricultural production at farm, catchment and national scale. The work programme will develop and prioritise the adaptations that might overcome this vulnerability; for example through technological innovations to improve P use efficiency and reuse of secondary sources of P and the necessary institutional infrastructure to support these. In parallel, the project will identify the biophysical, technological, socio-economic and institutional barriers to implementing improved P stewardship within catchments (for example by using less, recycling more and lowering end-user demand). This will be achieved through an in-depth analysis of the catchment heterogeneity that influences how P inputs affect agriculture, water quality and cascading ecosystem services and an assessment of the adaptive capacity of stakeholders to implement optimal P stewardship solutions. A multi-actor platform involving stakeholders at local to global scales will ensure end-user engagement and integration for maximum research impact. The project will deliver the first P vulnerability assessment for the UK food chain and identify potential adaptation strategies for improved P stewardship to help maximise the resilience and sustainability of the UK food chain.

Sustainable management of phosphorus (P) is vital for the resilience and security of the UK food system, and the delivery of ecosystem services (ES) such as clean water and biodiversity. Fertilisers and feeds are derived from phosphate rock, a critical, costly and finite resource, whose scarcity or fluctuating cost (P shocks) could threaten the UKs food security. Phosphorus is also an endemic water pollutant due to inefficiencies in the food chain. Improved stewardship of P is therefore urgently needed both to increase the resilience of the UK food system to P shocks and enable the sustainable intensification of UK agriculture. This project aims to enhance the resilience and sustainability of the UK food system by developing adaptive strategies that will reduce the vulnerability of UK farming to future P shocks and optimise the provision of ES. This will require an interdisciplinary approach, as vulnerability is defined by the human, physical, social, natural, and financial capitals that determine the capacity of stakeholders to make adaptations to current P use. This 3-year project will develop methods to characterize the effects of biophysical, social and institutional heterogeneity in catchments on the response of different ES to P inputs and the vulnerability to P shocks. This will enable the identification of farm and catchment scale adaptation strategies for sustainable P management practices to overcome P vulnerability and enhance ES. The project will also deliver the first national P vulnerability assessment for the UK food system and identify priorities for a National Adaptation Strategy. The project will result in novel outputs that integrate catchment biophysical and socio-economic variability into a suite of co-developed, context-specific, and implementable P measures and adaptive strategies that will increase the sustainability and resilience of the UK food system.

The sustainable management of phosphorus at farm catchment and national scale is highly relevant to multiple stakeholders including policymakers and regulators, the agri-food industry, the water industry and the general public. The project has a primary focus on stakeholder engagement through the formation of a Multi-Actor Platform (MAP) covering local, national and global networks and through this stakeholder interaction, the project will therefore have considerable potential research impact:

Policymakers (e.g. Defra) - the vulnerability of the UK food system to future phosphorus scarcity has not previously been assessed. The project will provide evidence to underpin where policy interventions might be necessary to (a) improve the efficiency and sustainability of phosphorus use at multiple scales, (b)to develop a circular phosphorus economy in the UK and (c) sustain the future competitiveness and resilience of UK agriculture and the UK food system.

Water Regulators (e.g. EA) - phosphorus is the primary cause of waterbodies failing to achieve good ecological status in many areas of the UK and regulatory standards to control costly eutrophication are based on phosphorus. The project will provide key indicators of how phosphorus (5R) stewardship can be implemented in catchments for the benefit of water quality and where eutrophication control standards are most likely to be met as agriculture intensifies.

Agri-ffod Industry (e.g. AHDB) - phosphorus scarcity could have a major impact on agricultural productivity and the project will identify the thresholds at which productivity might be affected by P shocks, and what secondary sources of phosphorus may be cost-effectively re-utilised to reduce UK dependence on expensive P fertiliser and feed imports. Phosphorus vulnerability assessments will also highlight where agricultural industries need to innovate for improved efficiency and sustainability of phosphorus use. Understanding catchment heterogeneity to P inputs will help farmers to manage phosphorus more sustainably to meet increasingly stringent regulatory standards for water quality protection.

Water Industry (e.g. Water Companies)- Water companies are at the forefront of phosphorus recovery technologies for wastewater and actively involved in catchment management to improve water quality. The project will provide the evidence to underpin where technology innovation is most urgently needed.

General Public (e.g. Rivers Trusts) - society is generally unaware of the dependency of the UK food system on phosphorus, the environmental impact of phosphorus use in the UK food system or the importance of dietary choice on the future resilience and sustainability of the UK food system. The project will provide key data to address this gap.