PhD Studentship: Biochar for Soil Health to Boost the Environmental Sustainability of British Hop Production

Closing date: 10 November 2024

Interview date: 22 November 2024

Start date: 20 January 2025

The project

Applications are invited for this full-time PhD studentship, which for UK home students is fully funded* by the Worshipful Company of Brewers, Asahi, Sainsbury’s, and the Royal Agricultural University.

Background

The UK is aiming to achieve net zero for agriculture by 2040 (NFU). Whilst this is a challenging goal, it presents numerous opportunities for farmers and land managers to not only directly reduce their greenhouse gas emissions, but also engage with actions that will result in greater carbon storage on land.

The management of British hop yards is focussed on overriding concerns with Verticillium Wilt (VW) due to its potential to decimate production, but also yield impacts due to competition from vegetation growing in alleyways between rows of hop bines. As the incidence of VW can be increased through the presence of vegetation in alleyways, growers prefer to maintain alleyways as bare soil throughout the year, which in turn impacts soil health. Regular cultivation and the use of herbicides to keep alleyways bare not only releases soil carbon, it is also carbon intensive.

Good soil health is one of the first lines of defence against soil-borne plant pathogens (Nwokolo et al., 2021), and as such, actions to reduce the incidence of VW in hop yards through vegetation removal can reduce the soil’s capacity to protect against financially important pathogens like VW (Ahmed & Galaup, 2022). Hop growers therefore need to focus on improving and maintaining soil health, especially with regards to the microbial community.

The value of biochar in improving soil health has been demonstrated in a range of crop types although responses are not always consistent (Lévesque et al., 2022). The benefits include more diverse microbial communities (Jenkins et al. 2016) and therefore an increased potential to suppress soil-borne pathogens (Poveda et al., 2021), improvements in nutrient and water retention (Baronti et al., 2014), and more carbon being locked up in the soil (Vaccari et al., 2011).

Biochar can also be used for the remediation of soils contaminated with heavy metals (O’Connor et al., 2018; Gonzaga et al. 2022). This is especially relevant in the case of UK hop yards, where the top soil is often contaminated from the long-term use of copper-based fungicide sprays for downy mildew prevention and control, negatively impacting soil health and plant growth (Görl, et al., 2023). However, the benefits of biochar to support a more sustainable approach to hop production is yet to be explored in this context.

There are only 45 hop growers remaining in the UK, and the hops they produce are highly sought after, enabling producers to differentiate their beers using unique flavours and aromas. To help underpin this sector there is a need to support hop growers with research that will enable them to increase the resilience and viability of their businesses, whilst enabling them to meet sustainability goals.

The opportunity for hop growers to utilise the benefits of biochar is likely to be a game changer for the sector and therefore demands being investigated. Through a programme of controlled pot-based studies and field trials, the overall aim of this project it to investigate whether the application of biochar has the potential to improve soil health and suppress soil-borne plant pathogens (including Verticillium spp.), whilst also boosting carbon storage. A key aim is to provide robust management guidelines for hop growers. This will be achieved through the following objectives.

  1. Under controlled conditions (glasshouse), investigate the effect of different types of biochar and application rates on the growth of a commercially important hop variety ‘Fuggle’.
  2. Under controlled glasshouse conditions, investigate the efficacy of different types of biochar and application rates to suppress Verticillium spp. in hops.
  3. Apply biochar to alleyways in British hop yards and investigate the benefits/impacts on the performance of hop bines.
  4. Determine the efficacy of biochar in British hop yards to enhance soil health and suppress soil-borne plant pathogens.
  5. Determine the potential for biochar to increase soil carbon storage in the alleyways of hop yards, and its contribution to net zero farming.

Indicative methodology

At the University of Warwick, a pot-based glasshouse experiment will be undertaken to investigate the influence of a range different biochar types and amendment levels on VW disease development on hop bines. The performance of bines under the different biochar regimes will also be investigated to help inform the most beneficial biochar type and its application rate in the field.

Following the glasshouse study, working with the British Hop Association and Charles Faram & Co Ltd, field sites will be selected for study in Gloucestershire, Herefordshire, and Worcestershire. At each site three plots spatially separated for independence will be selected controlling for factors such as hop variety, age etc. One plot will be managed conventionally with alleyways being left bare, one will receive biochar applications only in year one, and one plot will receive biochar in two consecutive years. The best biochar type and application rate identified during the pot-based glasshouse will be applied to alleyway strips.

For the glasshouse study, effects of the different types and amendment levels of biochar on VW disease development will be evaluated by recording disease symptom development over time (yellowing, wilting, plant mortality), while at harvest (at a time when untreated control plants have a high disease incidence), roots and stems will also be assessed for presence of VW disease symptoms. Re-isolation of V. nonalfalfae will be attempted for selected plants to confirm infection. Additionally, at harvest, fresh and dry weight of plants from each treatment will be recorded to determine any stunting effects of VW in inoculated treatments and any effects of biochar on hop growth in uninoculated controls.

Yields of hops will be compared between treatments to investigate whether the addition of biochar influences productivity. At each field site, the number and weight of hop cones from randomly selected bines will be determined for each of the three treatments.

To investigate the benefits of biochar on soil health and soil carbon storage, soil samples will be collected annually from the different biochar treatments. Samples will be analysed for soil organic matter, pH, and nutrient status. Soil texture will also be determined.

References

Ahmed, N. A. K., B. Galaup, et al. (2022). Ecosystem services provided by cover crops and biofumigation in sunflower cultivation. Agronomy-Basel 12(1).

Baronti S, Vaccari FP, et al. (2014). Impact of biochar application on plant water relations in Vitis vinifera (L.) European Journal of Agronomy 53:38–44.

Gonzaga, M. I. S., J. C. D. Santos, et al. (2022). Copper uptake, physiological response, and phytoremediation potential of Brassica juncea under biochar application. International Journal of Phytoremediation 24(5): 474-482.

Görl, J., D. Lohr, et al. (2023). Co-Composting of hop bines and wood-based biochar: effects on composting and plant growth in copper-contaminated soils. Agronomy-Basel 13(12).

Jenkins JR, Viger M, Arnold EC, Harris ZM, Ventura M, Miglietta et al. (2016). Biochar alters the soil microbiome and soil function: results of next-generation amplicon sequencing across Europe. GCB Bioenergy 9:591–612.

Lévesque, V., M. Oelbermann, et al. (2022). Biochar in temperate soils: opportunities and challenges. Canadian Journal of Soil Science 102(1): 1-26.

Nwokolo, N. L., M. C. Enebe, et al. (2021). The contributions of biotic lines of defence to improving plant disease suppression in soils: A review. Rhizosphere 19.

O'Connor, D., Peng, T., et al. (2018). Biochar application for the remediation of heavy metal polluted land: a review of in situ field trials. Science of the total environment, 619: 815-826.

Poveda, J., A. Martínez-Gómez, et al. (2021). The use of biochar for plant pathogen control. Phytopathology 111(9): 1490-1499.

Vaccari, F. P., S. Baronti, et al. (2011). Biochar as a strategy to sequester carbon and increase yield in durum wheat. European Journal of Agronomy 34(4): 231-238.

Details of the studentship

The studentship is offered for a four-year period on a full-time basis starting in January 2025. The studentship is campus based in Cirencester, but will involve travel to the University of Warwick, and travel to field sites in Gloucestershire, Herefordshire, and Worcestershire. During the period of your studentship, you will receive the following:

  • A tax-free annual stipend of £19,237 for three years.
  • A fee-waiver for four years for UK home students* (expectation that full-time students complete in three years. If you enter year 4, the bursary stops but fees are waived).
  • A budget to support your direct project costs, including dissemination costs.

*International students are welcome to apply but the difference in home and international fees currently at £5,500 and £18,050 per year respectively, would have to be paid each year by the student.

As a PhD student, you will be expected to play an active role in the life of the Royal Agricultural University. You will also be given opportunities to gain experience in learning and teaching under the guidance of your Supervisory team.

Application process

To apply please complete the application form below:

Application form for RAU PhD Studentship

It is expected that applicants will have the following qualifications / experience. In your application it is important to indicate how you meet these expectations:

  • A Masters degree in a relevant discipline e.g., soil science, environmental science, or equivalent professional experience.
  • A First or Upper Second (2.1) Honours Degree.
  • Ability to contribute to the research design of the project.
  • Experience of relevant research methods and skills.
  • Experience of soil sampling and lab analysis.

It is also expected that applicants will be able to demonstrate the following:

  • A sound understanding of and interest in both the project and the wider subject area.
  • Proficiency in oral and written English.
  • Computer literacy.
  • Ability to organise and meet deadlines.
  • Good interpersonal skills.
  • Ability to work independently and as part of a team.

The interview

In person interviews will be held on 22 November 2024. Shortlisted candidates will be given at least seven days’ notice. In advance of the interview, shortlisted candidates will be asked to submit a sample of their written work (e.g. a publication or a dissertation). Alongside the interview, shortlisted candidates will be asked to give a 15-minute presentation on a piece of research they have previously undertaken (10 mins) and their ideas for the PhD (five minutes). The formal interview will last approximately 40 minutes.

Supervisory team

Primary Supervisor:

Professor Duncan Westbury, Royal Agricultural University

Co-Supervisors: 

Dr David O’Connor, Royal Agricultural University

Professor John Clarkson, University of Warwick

For further information or an informal discussion on this project, please contact Professor Duncan Westbury (Primary Supervisor) via email (duncan.westbury@rau.ac.uk).