PhD position on clay addition as an emission reduction measure in peat soils (1.0 FTE):

Dutch peat soils under agricultural usage emit large quantities 5,6 Mt CO2-eq/yr) of greenhouse gasses as a result of peat degradation. Laboratory incubations show that clay amendments can slow down degradation and thus CO2 emissions. This PhD project aims to understand the mechanisms involved in this decrease, as part of the Peat Innovation Program of The Netherlands

As a PhD candidate, you will investigate the effect of clay addition on microbial peat degradation. You will test a series of hypotheses to unravel the dominant mechanisms of the observed reduction in degradation rates. You will study the relationship between clay additions and CO2 production across a range of scales and levels of complexity, by means of laboratory incubations, mesocosms experiments and field plot studies (clay palette).

More specifically, in this PhD project you will focus on four key questions: 

  • What is the effect of clay addition on the pore size distribution and oxygen availability in peat soils?
  • What is the effect of clay addition on the resource availability for heterotrophic microorganisms
  • What is the effect of clay addition on the microbial community composition and activity?
  • Which clay and peat properties control the respiration reduction potential?  

In your research, you will combine methods from biology, physics, chemistry and agronomy to understand and optimize clay addition as a greenhouse gas emission mitigation measure. You will use molecular research techniques to characterise the composition and activity of the microbial community in response to clay treatments and study clay reactivity to understand binding capacity and the formation of organo-mineral complexes in peat soils.

Ultimately, the aim is to understand and optimize clay addition to peat soils as a climate change mitigation measure for peat meadow regions. You will incorporate the data from this research into 4 scientific publications and get the opportunity to present your results at national and international conferences. 

The position is part of VIP-NL KiV, a larger project in which both fundamental and applied aspects of clay addition will be studied.


You are enthusiastic and motivated to contribute to our research as a PhD student and be part of a committed group of researchers. We would also like you to bring:

  • a Master’s degree or equivalent in Ecology, Microbial Ecology, Soil Science or Biogeochemistry;
  • a strong interest in mechanistic soil ecological research;
  • a good command of academic English both orally and in writing;
  • the ability to perform both independently and as part of a team;
  • good organisational and communication skills;
  • possession of driving licence B is considered an asset.


  • A full-time appointment (1.0 fte) for four years in a dynamic international working environment at the Ecology and Biodiversity group of Utrecht University;
  • A full-time gross salary that starts at €2541 in the first you and increases to €3247 per month in the fourth year (scale P of the Collective Labor Agreement Dutch Universities);
  • 8% holiday bonus and 8.3% end-of-year bonus;
  • A Pension scheme, partially paid parental leave, and flexible working conditions external link based on the CAO Dutch Universities.

In addition to the employment conditions from the CAO for Dutch Universities, Utrecht University has a number of its own arrangements. These include agreements on professional development, leave arrangements and sports. We also give you the opportunity to expand your terms of employment through the Employment Conditions Selection Model. This is how we encourage you to grow.

About the organisation

A better future for everyone. This ambition motivates our scientists in executing their leading research and inspiring teaching. At Utrecht University the various disciplines collaborate intensively towards major societal themes. Our focus is on Dynamics of Youth, Institutions for Open Societies, Life Sciences and Sustainability.

At the Faculty of Science there are 6 departments to make a fundamental connection with: Biology, Chemistry, Information and Computing Sciences, Mathematics, Pharmaceutical Sciences and Physics. Each of these is made up of distinct institutes that work together to focus on answering some of humanity’s most pressing challenges. More fundamental still are the individual research groups – the building blocks of our ambitious scientific projects.

You will work in the Ecology and Biodiversity research group at Utrecht University. The central research theme of the group is to understand how ecosystems respond to changes in climate and land use. We want to use novel insights gained in ecosystem responses to inform future policy and management.

Within the Ecology and Biodiversity research group, extensive experience has been gained in research on peatland regions. In addition, the research group has been working for some time on the effects of microbial community composition on ecosystem services in response to changing climate and land use. The focus of the group is on effects of drought, flooding and of nitrogen addition on soil carbon storage.

Additional information

If you have any questions about this position, please contact Mariet Hefting (Associate Professor) via Questions about the application procedure? Please email


Everyone deserves to feel at home at our university. We welcome staff with a wide variety of backgrounds and perspectives. If you have the expertise and experience to excel in this role, please respond via the “Apply” button!

Please enclose:

  •  cover letter;
  • curriculum vitae;
  • names, phone numbers and email addresses of at least two references;
  • copy of your MSc certificate, or a letter from your university stating when your defence will take place.

The start date for the position is preferably as soon as possible. The application deadline is 19 December 2022.

Apply now

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