Applications are invited for a PhD fellowship/scholarship at Graduate School of Technical Sciences, Aarhus University, Denmark, within the Agroecology programme. The position is available from 1 February 2022 or later.

Research area and project description:
One of the main threats to the quality of agricultural soil in Europe and elsewhere is soil compaction, mainly due to excessive and heavy traffic in non-optimal soil conditions. Over the past decades, machinery has become increasingly heavy and more powerful, thereby increasing stresses exerted on soil. When the strength is exceeded, the soil structure changes and the ability of a soil to deliver its functions (e.g. provide food, habitat, flood regulation and nutrient recycling) can be seriously hampered. Detrimental effects of soil compaction are persistent in the subsoil. Reducing this risk is therefore essential. The effect of a passing wheel on soil strength and structure is complex and not all machine-soil interactions are yet understood. For example, recent results reported the negative effects on soil structure from the forces exerted on soil through traction. This is not included in any soil compaction model yet. In addition, state-of-the-art soil compaction models derive from civil engineering and consider soil as a homogeneous medium with a distinct threshold between elastic and plastic behaviour. However, agricultural soils are structured and aggregated in a hierarchical system.

The aim of this PhD study is to improve our understanding of the mechanical behaviour of structured soil during traffic. Especially, one objective will be to develop a method to account for the influence of traction on the vertical and horizontal contact stresses between the tyre or track and the soil. A second objective will be to improve our understanding of the stress-strain relationship in order to predict the risk of compaction more accurately. The study will be a part of the GUDP project “SolGras”, which aims at developing a new decision support system (DSS) for planning of field traffic for grass harvesting to optimize yield, ensure soil protection, and work efficiency.

For this PhD project, we are looking for candidates with qualifications in soil physics and soil mechanics, and a strong interest in experimental work and numerical modelling. Other relevant competences include data collection and analysis and in general good computational skills.

You will be part of a team of researchers working on soil physics and soil mechanics with many years of experience with the evaluation of the effects of agricultural practices on soil functioning and ecosystem services.

Qualifications and specific competences:
Applicants to the PhD position must have a relevant Master’s degree within soil science, soil physics, soil mechanics, biosystems engineering or similar.

Place of employment and place of work:
The place of employment is Aarhus University, and the place of work is Foulum Research Center, Blichers allé 20, DK-8830 Tjele, Denmark. 

Contacts:
Applicants seeking further information are invited to contact:
Senior Researcher Mathieu Lamandé, mathieu.lamande@agro.au.dk

How to apply:
Please follow this link to submit your application. Application deadline is 15 December 2021 at 23:59 CET. Preferred starting date is 1 February 2022.

For information about application requirements and mandatory attachments, please see our application guide.

Shortlisting will be used, which means that the evaluation committee only will evaluate the most relevant applications.

All interested candidates are encouraged to apply, regardless of their personal background. Salary and terms of employment are in accordance with applicable collective agreement.

Aarhus University’s ambition is to be an attractive and inspiring workplace for all and to foster a culture in which each individual has opportunities to thrive, achieve and develop. We view equality and diversity as assets, and we welcome all applicants.

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