Increased research effort has been directed toward the solution of soil compaction problems in the past few years. Research workers dealing with these problems have been handicapped for at least the following four reasons: 1 Lack of definition and understand­ing of soil stress and soil compaction; a need for a suitable mathematical model 2 Lack of suitable recording equip­ment for measuring changes in soil physical phenomena, particularly soil compaction 3 Lack of basic engineering infor­mation about the mechanics of agri­cultural soils 4 Lack of adequate information showing the effect of certain parameters (soil moisture, soil type, and others) upon soil properties.