Compaction results when the pressure from a heavy object is applied to the surface of the soil.
All soils can be affected by compaction. In order to understand better what the shrinking causes, soil pores must be defined. Pore spaces, also called voids, are the portion of the soil volume not occupied by mineral or organic solids. These pores are the result of irregular shapes of particl es in the soil structure. The passage of equipment over the soil surface is generally involved in the modern agricultural reason for soil compaction.