PhD fellowship in Soil Fertility

The Department of Plant and Environmental Science (PLEN) invites applicants for a PhD fellowship in Soil Fertility. The project is part of the research project “Can microbial phosphorus mobilization be primed? Organic fertiliser effect on biological soil phosphorus cycling (PRIME-P)”, which is financed by the NovoNordisk Foundation.

Start date is 1 August 2026 or as soon as possible thereafter.

The project
Biobased fertilisers (BBF) exist in many forms (sewage sludge, compost, animal manures etc.) with different chemical properties, elemental composition and nutrient concentrations influencing their behaviour upon addition to soil. Unlike mineral phosphate fertilisers, many BBF contain significant amounts of organic phosphorus (P) and calcium phosphate forms, which are not directly available to plants. Soil microorganisms play a crucial role in the mineralization of organic P and the solubilisation of inorganic P, making microbial-driven soil P transformations essential for plant P availability when using BBF. Because of the relatively large carbon (C) and nitrogen (N) contents of BBF, soil organic matter may be signicantly modified, thereby affecting soil microbial activity. Plants, through their root exudates (soluble low-molecular-weight components such as sugars and organic anions), provide easily accessible forms of C that microorganisms can utilize in the rhizosphere. These exudates are continuously released by active roots, sustaining high microbial activity due to their bioavailability. The continuous supply of C in the rhizosphere can create a priming effect on various microbial activities by accelerating the decomposition of native and added stable soil organic matter. In C-limited soil environments, this could enhance organic P mineralization by promoting microbial activity through energy provision. Thus, plants can sustain microbial growth and activity, fostering microbial P mobilisation. This priming effect by root exudates is particularly relevant after the depletion of the available C pool added by BBF amendments, where a large proportion of C is in a stable form.

The main objective of the PhD project is to assess whether rhizosphere P cycling priming occurs in soils that have received BBF. The main research questions are: 1) Do labile C from root exudate promote microbial P mobilization? 2) Do the addition of BBF further promote microbial P mobilization in the rhizosphere? 3) Can the collected data of rhizosphere P priming be used to improve soil P modelling capacity?

To address these questions, activities will include root exudate simulation development using microdialysis, soil incubations to assess the effect of root exudates on C mineralization and microbial P processing on soils amended with BBF (using isotopic techniques (33P), imaging techniques, molecular tools (microbial gene expression of organic P mineralization - PhoC and PhoD), and may include the implementation of a soil-plant model in collaboration with another team member.

Principal supervisor is Asc. Prof. Dorette Müller Stöver and the project is led and co-supervised by Assist. Prof. Nelly S. Raymond.

Who are we looking for?
We are looking for candidates within the field(s) of soil biogeochemistry, soil biology, plant nutrition or a closely related discipline, with interest in fundamental and applied aspects of soil science and plant nutrition. We are seeking a motivated and ambitious individual with strong interpersonal and communication skills, as well as excellent spoken and written English. We encourage applications from candidates with a combination of the following or closely related competences:

• strong knowledge of, and interest in, soil biogeochemistry processes, with special emphasis on phosphorus, soil biology and soil organic matter dynamics.
• excellent experimental experience in laboratory work, including soil sampling and analyses, soil incubation, use of isotopic techniques, use of microdialysis etc.
• ability to translate theoretical scientific questions into practical experimental designs and measurement.
• ability to analyse and interpret complex datasets. Experience in modelling chemical transfers in soil would be an advantage.
• ability to work independently and take initiative, strong hands-on problem-solving skills, and the capacity to acquire new skills.

We recognize that research shows that women and other underrepresented groups often hesitate to apply unless they meet every requirement. If you are excited about this position and believe you can contribute, we strongly encourage you to apply, even if your experience does not perfectly match every qualification listed. We value curiosity, motivation, and the potential and willingness to learn.

Our group and research- and what do we offer?
The successful candidate will be anchored in the Soil Fertility and Nutrient Recyling group within the Plant and Soil section of the Department of Plant and Environmental Sciences, Faculty of SCIENCE, University of Copenhagen (https://plen.ku.dk/english/research/plant_soil/soil-fertility-and-nutrient-recycling/). The group is located at the Frederiksberg campus. Our research group addresses soil fertility challenges in sustainable agriculture, with a particular focus on nutrient recycling from organic waste materials of rural, urban and industrial origin. We aim to improve our understanding of how different recycling strategies affect soil nutrient and organic matter dynamics and soil ecosystem resilience. This knowledge supports improved nutrient recycling and use efficiency, enhanced crop productivity, and the promotion of soil health for the 21st century. We offer creative and stimulating working conditions in dynamic and international research environment. Our research facilities include modern laboratories, climate chambers and access to long-term field trials. As part of the Department of Plant and Environmental Sciences and the Faculty of Science, we have access to state of the art instruments and a wide range of methods relevant to soil biogeochemistry.

The PhD project involves collaboration among the University of Copenhagen, the Swedish Agricultural University (SLU), the University of Guelph (UG) and the CSIRO in Australia. The project supervisor at the University of Copenhagen is Assistant Professor Nelly S. Raymond, Department of Plant and Environmental Sciences. The principal supervisor is Associate Professor Dorette Müller Stöver. Prof. Anke Hermann (SLU) will be supervising the establishment of the reverse microdialysis work and Prof. Kari Dunfield (UG) will contribute to the microbial molecular work related to organic P mineralization.

The PhD programme

A three year full-time study within the framework of the regular PhD programme (5+3 scheme), if you already have an education equivalent to a relevant Danish master’s degree.

Qualifications needed for the regular programme
To be eligible for the regular PhD programme, you must have completed a degree programme, equivalent to a Danish master’s degree (180 ECTS/3 FTE BSc + 120 ECTS/2 FTE MSc) related to the subject area of the project, e.g. soil science, or biogeochemistry. For information of eligibility of completed programmes, see General assessments for specific countries and Assessment database.

Terms of employment in the regular programme
Employment as PhD fellow is full time and for maximum 3 years.

Employment is conditional upon your successful enrolment as a PhD student at the PhD School at the Faculty of SCIENCE, University of Copenhagen. This requires submission and acceptance of an application for the specific project formulated by the applicant.

Terms of appointment and payment accord to the agreement between the Danish Ministry of Taxation and The Danish Confederation of Professional Associations on Academics in the State. The position is covered by the Protocol on Job Structure.

Responsibilities and tasks in the PhD programme

• Carry through an independent research project under supervision
• Complete PhD courses corresponding to approx. 30 ECTS / ½ FTE
• Participate in active research environments, including a stay at other research institutions (TUB)
• Teaching and knowledge dissemination activities
• Write scientific papers aimed at high-impact journals
• Write and defend a PhD thesis on the basis of your project

We are looking for the following qualifications:

• Professional qualifications relevant to the PhD project
• Relevant publications
• Relevant work experience
• Other relevant professional activities
• Curious mind-set with a strong interest in the development of sustainable crop systems that are resource-use efficient, biodiversity-friendly and promote important ecosystem services
• Proficiency in spoken and written English, including skills in academic writing. Your command of the English language is expected to be at C1 level.

Application and Assessment Procedure
Your application including all attachments must be in English and submitted electronically by clicking APPLY NOW below.

Please include:

1. Cover letter/motivation letter for the application (max. one page)
2. Curriculum vitae including information about your education, experience, language skills and other skills relevant for the position
3. A short reflection on your research interests, experience, and how the project aims can be approached (max. one page)
4. Original diplomas for Bachelor of Science or Master of Science and transcript of records in the original language, including an authorized English translation if issued in another language than English or Danish. If not completed, a certified/signed copy of a recent transcript of records or a written statement from the institution or supervisor is accepted.
5. A statement on AI use for the application.
6. Publication list (if possible)
7. Contact information for two referees (to contact upon request)

Application deadline:
The deadline for applications is 15 May 2026, 23:59 GMT +2.

We reserve the right not to consider material received after the deadline, and not to consider applications that do not live up to the abovementioned requirements.

The further process
After deadline, a number of applicants will be selected for academic assessment by an unbiased expert assessor. You are notified, whether you will be passed for assessment.

The assessor will assess the qualifications and experience of the shortlisted applicants with respect to the above mentioned research area, techniques, skills and other requirements and will conclude whether each applicant is qualified. The assessed applicants will have the opportunity to comment on their assessment. You can read about the recruitment process at http://employment.ku.dk/faculty/recruitment-process/.

Interviews with selected candidates are expected to be held in week 23-24, 2026.

Questions
For specific information about the PhD fellowship, please contact Assistant Professor Nelly S. Raymond (nray@plen.ku.dk). This email address is provided exclusively for questions about the position. Applications, CVs, or any other unsolicited materials will not be reviewed and will be permanently deleted without being opened, in compliance with applicable data protection regulations. All applications must be submitted through the official application portal as specified in the job advertisement.

General information about PhD study at the Faculty of SCIENCE is available at the PhD School’s website: https://www.science.ku.dk/phd/. https://www.science.ku.dk/phd/

The University of Copenhagen wishes to reflect the surrounding community and invites all regardless of personal background to apply for the position.