Investigation of relationships between measured field indicators and erosion processes on badland surfaces at Petrer, Spain

Indicators were obtained to measure and predict rill erosion and mass wasting in biancana and calanchi-like badland areas. Rainfall simulation experiments were used to find a relationship between soil moisture change and sediment concentration behaviour. This relationship appeared to be able to show, in its role as indicator, differences between materials affected by various degrees of rill erosion or mass wasting. Indicators explaining this relationship are surface characteristics, runoff and infiltration characteristics and chemical and mineralogical soil properties. From the experimental study it was concluded that the high infiltration capacity in materials affected by mass wasting resulted in an unstable soil and a high degree of erodibility. The materials which were more affected by rill erosion or had a continuous crust at the surface were saturated earlier during the experiment than the other materials. This saturation caused an increase in runoff. The mechanism is explained as the system crossing a threshold after which flow hydraulics at the surface are more important for erosion processes than dynamic soil properties and infiltration characteristics.