Abstract: The automatic penetrometer developed by Cemagref of France was used to measure cross-sections of soil before and after being compacted by a tyre in an experimental soil bin The effects of pneumatic pressure,driving torque,loading and the number of tyre passes on soil compaction were analyzed The results provided guidelines for the correct use of tyres,selection of appropriate farm implements and developing new type of tyres for farming so as to reduce over-compaction of farmland