Estimating the aggregate/intraaggregate mass ratio of a shrinking soil

Abstract

A recently introduced parameter, the ratio of an aggregate solid mass to a solid mass of an intraaggregate matrix (K ratio) is connected with the mean thickness of a deformable, but non-shrinking surface layer of aggregates and is a fundamental property of aggregated soils that essentially influences their shrinkage. The objective of this work is to suggest and validate an approach to estimating the K ratio at any soil clay content through characteristics of soil texture and structure. We derive an equation that reflects the interrelation between the K ratio and soil texture and structure. The K ratio can be estimated as the solution of the equation and is determined by the mean size of soil solids and the maximum size of soil aggregates in the oven-dried state, independently of a measured shrinkage curve. To validate the approach we use available data for eight soils.