Jean-Thomas Cornelis

KU Leuven is offering a PhD position in rhizosphere biogeochemistry within the Department of Earth and Environmental Sciences, Soil and Water Management Division, in the SPIRAL lab. The project focuses on how soil formation , root exudation , and free-living nitrogen fixers interact in the rhizosphere. A key research question is how plant-released carbohydrates and carboxylates influence microbial nitrogen fixation and the mobilization of molybdenum (Mo) , an essential cofactor for nitrogenase. The study also examines the role of soil water status and dry–wet cycles in controlling these processes. As a doctoral researcher, you will work on soil-plant-water-microbe interactions using rhizoboxes, mesocosms and/or field experiments, 15N2 incubations, acetylene reduction, nifH-based analyses, batch experiments, soil fractionation, and advanced isotopic/geochemical methods. You will integrate the results into a conceptual and/or quantitative model of plant-soil feedbacks. The position is supervised by Prof. Jean-Thomas Cornelis and is embedded in an international, multidisciplinary environment. The group works on soil processes at micro scale and their effects on ecosystems at macro scale, with emphasis on soil–plant feedbacks, biogeochemical cycles, and ecosystem resistance, resilience, and recovery. Applicants should hold a master’s degree in soil science, environmental sciences, earth sciences, biology, chemistry, bioengineering, or a related discipline. A strong background in soil science and biogeochemistry is required, along with good English, curiosity, critical thinking, and the ability to work independently and in teams. Experience with plant experiments, rhizosphere sampling, exudate collection, soil analyses, stable isotopes, microbiology, or R/Python is considered an advantage. The fellowship is full-time and funded for 1 year initially, with the possibility of extension for another 3 years. KU Leuven also offers additional employee benefits such as hospitalisation insurance, discounted public transport, free bike use, sports facilities, and childcare. Applications must be submitted via the online application system by 16/11/2026 23:59 CET . Applicants should include a CV, a cover letter (max. 1 page), transcripts of bachelor’s and master’s studies, and contact details of two referees.