Shrinkage in Clayey Subsoils of Contrasting Structure

Summary Shrinkage was measured on subsoil samples from two clayey alluvial soils of contrasting structural development and two boulder clay soils also of contrasting structure. Of the four phases of shrinkage recognized, the proportion of shrinkage attributable to the structural shrinkage phase is shown to be dependent on structural development and organic carbon levels in the subsoil. The importance of structural shrinkage to the maintenance of good structure in clay soils under intensive cultivation is briefly discussed.