ABSTRACT
Soil shrinkage is the reduction in bulk volume that occurs during drying. It occurs to varying
degrees in all soils but most extensively in soils containing appreciable amounts of expand-
ing lattice (smectitic) clays, especially when they are sodic (Parker et al. 1977; Boivin et al.
2004). Also, if a soil shrinks, it can usually swell again, but hysteresis in volume change is
common in clays, so shrinkage is not always truly reversible (e.g., Haines 1923; Holmes
1955; Chang and Warkentin 1968). Despite the big differences between shrinkage and
swelling processes, however, shrinkage has long been used to indicate a soil’s shrink-swell
capacity (e.g., Franzmeier and Ross 1968; Ross 1978; De Jong et al. 1992), and to indicate its
mechanical workability and its potential for crop performance (Auchinleck 1912). Further-
more, the integrity of engineering structures (Jumikis 1984; Gillot 1986), the potential for
pollution of groundwater through cracks (Coles and Trudgill 1985), the regeneration of
damaged soil structure (Pillai-McGarry and McGarry 1999), and the availability of soil water
under modest overburdens (Groenevelt and Grant 2001; Groenevelt et al. 2001) all depend
on the shrink-swell properties of a soil.
