• 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 a 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  which 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.