• Semester 1 (Day)

Synopsis

Agriculture machinery interacts with soils in a number of ways, and so
the  processes  of  tillage,  traction and  compaction  are  of  vital
interest  to  engineers involved in agriculture. This  unit  considers
these  processes by way of developing a detailed understanding of  the
response of soils to imposed stresses and their resulting deformations
and modes of failure. It uses both classical soil mechanics and recent
developments  in the application of Critical State soil  mechanics  to
unsaturated  soils to establish a theoretical framework that  explains
and describes the action of tillage tools, the development of tractive
forces, and the process of compaction.

The  unit  provides  a  basic understanding of  the  process  of  soil
disturbance  by  tillage  tools and outlines methods  for  calculating
tillage forces. It investigates the interface between tracks and tyres
and  a  soil  and  shows how this knowledge may  be  used  to  predict
tractive  forces.  This knowledge is also important in  developing  an
understanding  of  soil  compaction and  its  consequences  for  plant
growth.  Methods for measuring and describing soil structure are  also
discussed.