Name of course:
Soil Deformation and Fragmentation: Visualization, Measurements, Modelling and Functioning

ECTS credits:
5 ECTS

Course parameters:
Language: English
Level of course: PhD
Time of year: 18-23 March 2019
No. of contact hours/hours in total incl. preparation, assignment(s) or the like: 70/140
Capacity limits: 20

Objectives of the course:
The course will present classical and new approaches for measurement, modelling, and visualization of soil deformation and fragmentation due to mechanical stress application.

Some of the concepts and theory classically used in agricultural soil mechanics and adopted from geomechanics (analytical solutions for stress propagation in soil, soil compressive strength, structural stability) have limitations that will be illustrated with hands-on modelling and measurements in the lab (uniaxial confined compression, uniaxial unconfined compression, rotational shear) and in the field (penetration resistance, rotational shear, vertical and mean normal stress beneath vehicles). Discrete Element Models will be presented as an alternative modelling approach for soil deformation, fragmentation and movement. Mechanical behaviour of agricultural soils at the macroscale in a context of mechanical tillage will be investigated using measurements of soil aggregate tensile strength and stability. Three-dimensional imaging techniques will be presented to visualize how and where the soil structure is affected by tillage and traffic (photoelastic methods, CT scan). Simple experiments illustrating the consequences of soil mechanical stress application on soil physical functioning in terms of aeration, water transport and root penetration will be performed by the students.

Learning outcomes and competences:
At the end of the course, the student should be able to:

• Determine traditional soil mechanics parameters from measurement in the field and the lab
• Determine air and water transport parameters from measurements in the lab
• Evaluate trafficability and workability in a given scenario
  
  

Compulsory programme:
Participants must be present and active during the whole week in order to have their performance assessed.

Course contents:
General Aspects of the Mechanical Behaviour of soils

• Stress theory;
• Strain theory;
• Stress-strain relations.
  
  

Traditional Soil Mechanics Modelling

• Elastic stress-strain relationships (Pseudo analytical solutions).
  
  

Traditional Soil Mechanics Measurement Methods

• Laboratory and field methods to measure compressive behaviour of soil;
• Laboratory and field methods to measure shear strength;
• Laboratory method to measure tensile strength;
• Laboratory method to measure aggregate stability;
• Laboratory and field method to measure penetrometer resistance.
  
  

Advances Soil Physics

• Consequences of soil deformation and fragmentation on soil physical functioning
• Effects on aeration, water transport, root growth, crop establishment–theory
• Laboratory exercise
  
  

New Approaches to Infer Soil Mechanical Models

• Particle arrangements measurements using three-dimensional imaging techniques.
  
  

New Approaches to Model Soil Mechanical Behaviour

Distinct Element Modelling.

Prerequisites:
Course opened to Ph.D. students with a background in soil science, environmental engineering, numerical modelling.

Name of lecturers:

• Thomas Keller (Agroscope, CH)
• Blair McKenzie (James Hutton Institute, UK)
• Jan De Pue (Ghent University, B)
• Lars Munkholm (AU)
• Per Schjønning (AU)
• Mathieu Lamandé (AU)
  
  

Type of course/teaching methods:
The course will last six days. Each day will begin with a lecture session. The second half of the day will involve hands-on modelling and measurement activities.

Literature:
The participants will get preparatory readings for one-week workload.

Course homepage:
http://agro.au.dk/phd-uddannelse/phd-kurser-hos-institut-for-agrooekologi/soil-deformation-and-fragmentation-2019/

Course assessment:
On the 6^th day the participants must participate in a young scientist forum, where the aim is exchange of knowledge, experience, and ideas. Each student must give a presentation of their work in relation with a topic from the content of the course.

Provider:
Department of Agroecology, Aarhus University

Special comments on this course:
The course fee will be around 600 Euro – read more at the course homepage.

Time:
18-23 March 2019

Place:
Aarhus University Foulum, Blichers Allé 20, DK-8830 Tjele

Registration:
Expression of interest via this link https://events.au.dk/SoilDeformation2019 by 20 January 2019 at the latest. We will then come back to you with further information.

If you have any questions related to the scientific part, please contact Mathieu Lamandé, mathieu.lamande@agro.au.dk.

If you have any question related to practical matters, please contact Jytte Christensen, jytte.christensen@agro.au.dk.