The dynamics of aggregate breakdown as a function of dispersive energy

摘要

This paper reports on the distribution of soil aggregates for Vertosols and Ferrosols as a function of the energy involved in dispersion, known as the dispersive energy. For Vertosols showing an aggregate hierarchy, the breakdown of aggregates is modelled using the aggregate liberation and dispersion characteristic curve indicating a stepwise breakdown of soil aggregates. Meanwhile, for Ferrosols, during dispersion the 2-50 mum aggregates increases monotonically with increasing dispersive energy, which is indicative of the direct release of silt and clay from the disruption of aggregates. The exponential decrease in ultrasonic power over time for the Ferrosols, as opposed to the prominent drop or steps in the curves for the Vertosols, confirms the lack of a prominent aggregate hierarchy.