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Reference CTP-SAI-075

Double legumes, multiple benefits? Ecosystem service benefits from combined faba bean (Vicia faba L.) and pea (Pisum sativum L.) crop-mixtures.

Reference CTP-SAI-075

Double legumes, multiple benefits? Ecosystem service benefits from combined faba bean (Vicia faba L.) and pea (Pisum sativum L.) crop-mixtures.

Dr Pete Iannetta (The James Hutton Institute),
Dr Jacqueline Hannam (Cranfield University),
Prof. Euan James (JHI),
Prof Wilfred Otten (Cranfield University).
Roger Vickers (Processors and Growers Research Organisation ; PGRO)


Increased domestic legume production can contribute to Net Zero targets in the agricultural sector via reduction of greenhouse gas (GHG) emissions by offsetting the use of mineral fertiliser nitrogen (N) in the pea and bean crop, and for the following crop through biological nitrogen fixation (BNF). However, there are other multiple benefits of bean and pea cropping beyond yield and GHG reductions that include reduced dependence on feed-imports and improved soil health delivering multiple ecosystem services and functions.

The potential of UK-grown faba- or field-beans (Vicia fabaL.) and peas (Pisum sativum L.) as a pivotal crop for food- and feed-security is now being acknowledged. Currently, sustainable development objectives for UK farming seek to offset imports of soya via increased cultivation and advance feed formulation of domestically produced peas and beans. The EAT-Lancet Commission highlighted human consumption of legume grains should double (globally) by 2050 and thus developing home-grown grains for plant-protein based human food will serve an expanding market.

The BNF benefits of establishing beans (and peas) in rotations is well established but crop yields across the UK yield remain characteristically unstable. Intercropping of grain-legume combinations can improve yield stability, demonstrate BNF and soil health benefits and recent work has identified legume-legume intercropping also shows this potential.  However, there are currently knowledge gaps in legume-legume intercropping for: 1) optimising different varietal combinations; 2) assessing the additional benefits on ecosystem service delivery and improvements in soil health; and 3) the effects on BNF and follow-on crop N fertiliser offset potential and resulting GHG emission reductions.


The aim of the research project is to determine ecosystem service and soil health benefits of legume-legume intercropping optimised for protein yield potential.

The research has the following objectives:

Objective 1: Identify protein yield potential of different varietal combinations in legume-legume combinations. This will involve analysis of faba beans and peas harvested from Cranfield University glasshouse experiments and field trials at the Processors and Growers Organization (PGRO) and The James Hutton Institute. Plant performance and yield will include assessment of key physiological traits relating to growth and development at key life-cycle stages e.g., dates of flowering, pod-set/-fill, and harvest.

Objective 2: Establish novel field trials to quantify biological nitrogen fixation from air using the 15N natural abundance technique. These will assess yield potential, and feed-import offset potential of legume-legume combinations. New field trials will be established at PGRO and JHI, informed by the initial trials and the industrial partner, that will use targeted varietal combinations and compare with mono-cropped equivalent.

Objective 3: Determine and quantify N and C fluxes and flows, above and below ground, including effects on ecosystem services of water and air quality via leaching and GHG emissions, respectively. The impact of different above and below ground residue mixtures on soil nitrogen and carbon cycling, GHG emissions and pre-crop effect of following crops will be assessed.

Objective 4: Apply the data and insights in a (farm) carbon footprint accounting tool such as the Farm Carbon Tool to assess how pea-bean intercrops can minimise the carbon footprints of different farm types and contribute to Net Zero targets.


The student will be registered with Cranfield University and based at either Cranfield University or The James Hutton Institute, Dundee.


Students will have access to training in key bioscience areas (bioinformatics, statistics, and mathematics) to enhance employability and research capability.

The CTP – SAI ( is a groundbreaking partnership between leading businesses, charities and research providers offering outstanding training for the agri-food sector

All CTP-SAI students will receive the Leadership and Management training provided by MDS ( and will create their Personal Development Plan (PDP) to identify their development needs and areas of strength. Each student will receive individual coaching and mentoring with regards to their career plans and skills development (in addition to the scientific project supervision).

The student will be part of the Cranfield University Doctoral Research Core Development Programme which provides a suite of resources to develop transferable and key technical skills.


Placements are a key feature of CTP and UKRI-BBSRC expects all doctoral candidates on a CTP programme to undertake a placement. Placements can be in the form of research placements (3-18 months duration) or used more flexibly for experiential learning of professional skills for business and/or entrepreneurship. All placements are developed in collaboration between the partners with input from the doctoral candidate.


Contact Dr Pete Iannetta and Dr Jack Hannam for an informal discussion on the research content of this PhD.

This studentship will begin in October 2024. The successful candidate should have (or expect to have) an Honours Degree (or equivalent) with a minimum of 2.1 in Plant Science, Applied Statistics, or other related science subjects. Students with an appropriate Masters Degree are particularly encouraged to apply.

We welcome UK, EU, and international applicants. Candidates whose first language is not English must provide evidence that their English language is sufficient to meet the specific demands of their study. Candidates should check the requirements for each host organization they are applying to, but IELTS 6.5 (with no component below 6.0) or equivalent is usually the minimum standard.

This studentship is for four years and is fully funded in line with UKRI-BBSRC standard rates. These were for 2023/24, an annual maintenance stipend of £18,622, fee support of £4,596, a research training support grant of £5,000, and conference and UK fieldwork expenses of £300.

To be classed as a home student, candidates must meet the following criteria:

  • Be a UK National (meeting residency requirements), or

  • Have settled status, or

  • Have pre-settled status (meeting residency requirements), or

  • Have indefinite leave to remain or enter.

If a candidate does not meet the criteria above, they would be classed as an international student and must demonstrate the ability to meet the supplement in fees required for an international student.

Anyone interested should complete the online application form before the deadline of 7th January 2024. Interviews will be held during January 2024.

Please contact for further application details.

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NIAB logo transparent background_edited.jpg
NIAB logo transparent background_edited.jpg
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