Incorporating Crusting Processes in Erosion Models

Abstract

In most soils, surface crusting strongly influences the infiltration and erosion processes, so there is a need to include crusting in infiltration and erosion modelling. The processes involved in surface crusting, however, are extremely dynamic and crust characteristics are often difficult to measure. Significant progress has been made in describing crust formation. Aggregate breakdown and the displacement and reorganisation of detached soil units give rise to two general categories of surface crusts: structural and depositional. Modelling infiltration into these crusts has led to the development of equations of varying complexity, ranging from simple empirical equations to numerical solutions of the Richards equation. Obtaining the parameters for the more mechanistic approaches remains a challenge, and the equations need to be evaluated under field conditions where crust characteristics have a high spatial variability. For erosion modelling, surface crusting and erosion have many common processes, so crusting is implicitly present in some models. Further research should consider the potential for estimating the quantitative parameters needed for infiltration and erosion modelling from the descriptive studies of crusting processes and crust micromorphology.