PhD fellowship in Soil Fertility phosphorus

Start date: 1 January 2027 or as soon as possible thereafter.

About the role

The PhD fellowship is part of the research project “Can microbial phosphorus mobilization be primed? Organic fertiliser effect on biological soil phosphorus cycling (PRIME-P)”, financed by the NovoNordisk Foundation.

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.

The objective of the PhD project is to determine how additions of different BBF affect soil organic matter over time and influence microbial P mobilisation. The main research questions are:

• Do different forms of OM affect microbial P mobilization?
• Do the different OM fractions have similar levels of P mineralization?
• How do soil properties influence microbially mediated P cycling?

Activities will include:

• Soil characterization in relation to P availability
• Soil organic matter fractionation upon recent and historical BBF additions
• Soil incubation studies to investigate microbial P processing (using isotopic techniques (³³P and ¹⁸O enriched water) and measurements of enzymatic activity)
• Investigation of microscale mechanisms using advanced imaging techniques
• Potential implementation of a soil-plant model in collaboration with another team member

Requirements

We are looking for candidates within the field(s) of soil biogeochemistry, plant nutrition, or a closely related discipline, with interest in fundamental and applied aspects of soil science and plant nutrition. 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 and soil organic matter dynamics
• Excellent experimental experience in laboratory work, including soil sampling and analyses, soil organic matter fractionation, use of isotopic techniques
• Ability to translate theoretical scientific questions into practical experimental designs and measurements
• Ability to analyse and interpret complex datasets
• 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.

Qualifications

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.

Responsibilities and tasks

• 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 (Technische Universität Berlin)
• 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

About the research group

The successful candidate will be anchored in the Soil Fertility and Nutrient Recycling group within the Plant and Soil section of the Department of Plant and Environmental Sciences, Faculty of SCIENCE, University of Copenhagen. 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 a 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, Aarhus University (AU), Technische Universität Berlin (TUB), ETH Zürich, and the University of Guelph (UG).

Principal supervisor: Associate Professor Dorette Müller Stöver, Department of Plant and Environmental Sciences, E-mail dsst@plen.ku.dk, Phone +45 35331236.

Co-supervisor: Assistant Professor Nelly S. Raymond, Department of Plant and Environmental Sciences, E-mail nray@plen.ku.dk, Phone +45 35331839.

Prof. Carsten Müller (TUB) will be the daily project supervisor during research visits to TUB. Assistant Prof. Ingeborg F. Pedersen (AU), Dr. Federica Tamburini (ETH Zürich), and Prof. Kari Dunfield (UG) will serve as advisors on the project.

Terms of employment

Employment as PhD fellow is full time and for a maximum of 3 years. Employment is conditional upon successful enrolment as a PhD student at the PhD School at the Faculty of SCIENCE, University of Copenhagen. 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.