Understanding legume nitrogen dynamics and their implications for greenhouse gas mitigation in regenerative agriculture PhD

We invite applications from ambitious life-science graduates for a fully funded PhD at Cranfield University, supported by the EPSRC Doctoral Landscape Award. The award covers Home fees (£5,238 p.a.) and provides a £24,500 annual tax-free stipend for three years. Based in the Cranfield Environment Centre, the student will investigate how legumes shape nitrogen cycling, crop performance and greenhouse-gas emissions in regenerative arable rotations, developing science to support sustainable, lower-input farming and UK Net Zero goals.

UK agriculture produces around 70% of national nitrous oxide emissions, a greenhouse gas with 273 times the global warming potential of carbon dioxide over 100 years. Much arises from inefficient nitrogen fertiliser use. Legumes can reduce this reliance by fixing atmospheric nitrogen, removing synthetic nitrogen fertiliser requirements for themselves and potentially reducing requirements for following crops. Yet we cannot reliably predict when, where or how much legume-derived nitrogen becomes available. This limits farmers' ability to adjust subsequent fertiliser applications and realise the full economic and environmental value of legumes.

This PhD will uncover how legumes regulate soil nitrogen cycling across arable rotations. The student will quantify effects on subsequent cereal yield, nitrogen-use efficiency, greenhouse-gas emissions and fertiliser-replacement potential under contrasting arable management systems. Field, laboratory and controlled-environment experiments will determine when and where legume-derived nitrogen becomes available within bulk soil and the rhizosphere. Conventional soil mineral nitrogen testing will be compared with detailed measurements of mineralisation, biological nitrogen fixation, crop nitrogen uptake and microbial processes. The research will test whether this deeper nitrogen accounting can deliver worthwhile financial and environmental gains over current practice.

This EPSRC-funded studentship will be based in the Cranfield Environment Centre, whose research spans soil and air quality, climate change, crop monitoring, resilience and ecosystem services. The project also offers close collaboration with the James Hutton Institute, an internationally recognised centre for sustainable-cropping research. Hutton scientists will provide co-supervision, expertise in legume agronomy and biological nitrogen fixation, and specialist training during a placement in Dundee, linking mechanistic science with field evidence and practical nitrogen management recommendations.

This research will strengthen nitrogen fertiliser recommendations after legumes, helping farmers and agronomists reduce unnecessary inputs, costs and emissions without compromising crop performance. Findings will be incorporated into farm carbon accounting tools, translating new knowledge into practical whole-farm decisions. The work will advance lower-input, resource-efficient cropping systems and identify where legume-based rotations can deliver the greatest agronomic and environmental benefits while supporting UK Net Zero.

The student will work with established field trials and industry-relevant datasets from Nitrogen Climate Smart, LegumES and the James Hutton Institute's Centre for Sustainable Cropping. A placement in Dundee will provide specialist experience of long-term cropping-system research. Opportunities will include UK fieldwork, engagement with farmers, agronomists and industry through project events, Groundswell and the Pulse Crop Genetic Improvement Network, and presentation of findings at national and international conferences, including the UK Legume Research Community and International Legume Society conferences.

The student will gain integrated training in field experimentation, laboratory and controlled-environment research, soil–plant–microbial science, greenhouse-gas assessment and quantitative analysis. They will also develop skills in project management, scientific writing, grant development, stakeholder engagement and communicating evidence to academic, farming, industry and policy audiences.

Entry requirements: Applicants should have a first or second class UK honours degree or equivalent in a related discipline. This project would suit graduates from a wide range of backgrounds such as soil science, environmental science, agronomy, plant science, ecology or related disciplines. Experience of, or a strong interest in, fieldwork, laboratory analysis and quantitative data analysis (e.g., R) would be beneficial, though full training will be provided.

This studentship is open to both Home and Overseas fee status students, however a limited number of studentships are available to students with Overseas fee status.

Supervisors: Prof Wilfred Otten (1st Supervisor), Dr Emily Guest (2nd Supervisor).