During his PhD studies, Esben Øster Mortensen investigated perennial grassland mixtures and their ability to increase soil carbon input and storage. Legumes (e.g., clover) reduce the need for nitrogen fertilizers by fixing nitrogen from the atmosphere, while forbs such as chicory and ribwort plantain enhance root biomass and carbon input to deeper soil layers. Esben Øster Mortensen shows through his research how well-designed mixtures with grasses, legumes, and forbs can increase carbon input to the soil while maintaining high, stable yields with much lower Nitrogen fertilizers than grass monocultures.

The findings contribute to the green transition by demonstrating how biomass can be produced with reduced climate and environmental impacts, and by identifying soil-plant interactions that govern soil carbon storage.

The PhD study was completed at Department of Agroecology, Faculty of Technical Sciences, Aarhus University.

This summary was prepared by the PhD student.

Time: Tuesday, 18 March 2025 at 10:00
Place: Building 8814, room 3075 (Auditorium), Department of Agroecology, Aarhus University, Blichers Alle 20, 8830 Tjele
Title of PhD thesis: Carbon and nitrogen dynamics in productive grasslands: the role of species traits and mixture composition
Contact information: Esben Øster Mortensen, e-mail: eom@agro.au.dk, tel.: +45 93 52 12 62,
Members of the assessment committee:
Professor Christine Watson, Department of Rural Land Use, Scotland's Rural College, Scotland
Senior Researcher Katja Klumpp, Grassland Ecosystem Research Unit, INRAE, Clermont-Ferrand, France.
Senior Researcher Anne Grete Kongsted (chair), Department of Agroecology, Aarhus University, Denmark
Main supervisor:
Senior Researcher Jim Rasmussen, Department of Agroecology, Aarhus University, Denmark
Co-supervisor:
Senior Researcher Diego Abalos, Department of Agroecology, Aarhus University, Denmark
Language: The PhD dissertation will be defended in English

The defence is public.
The PhD thesis is available for reading at the Graduate School of Technical Sciences/GSTS, Ny Munkegade 120, building 1521, 8000 Aarhus C.