Modelling of soil fragmentation dynamics

An understanding of soil fragmentation during aggregate breakdown is useful in studies of erosion, tillage and traffic. Modelling efforts in soil fragmentation has largely focussed on characterisation of the size and mass distribution of aggregates using fractal approach and less on the nature and magnitude of the applied energy that produces fragmentation. In this paper, we report a model of soil fragmentation that assumes soil to comprise two fractions: a strongly bound fraction (primary particles) and a weakly bound fraction (aggregates). As the energy input on the soil increases, fragmentation of some of the weakly bound fraction produces an increase in the amount of primary particles. For simplicity, only three size classes of primary particles (sand, silt and clay) are considered. Results show that the model can be applied to soils of a wide range of structures and is capable of producing improved description of aggregate hierarchy. Application of the model to studies of tillage and erosion is discussed.