Soil aggregate stability in three Mediterranean environments

Abstract

This paper considers the effect of vegetation on soil aggregate stability in three different Mediterranean landscapes in Southeast Spain. Soils on limestone, marls and clays, with two levels of vegetation cover at each north-facing slopes of the study areas, were investigated. Three aggregate stability tests (CND, TDI and UD) based on the drop impact and ultrasonic dispersion methods and the Emerson dispersion test were performed. The results of the experiments show the positive influence of vegetation on aggregate stability. However, vegetation is less important than lithology in influencing soil aggregate stability. Soil depth and moisture also affect aggregation, but the relationships are different for each soil type. Soil aggregate stability reflects the operation of a highly complex system, in which vegetation, lithology, water content and depth, amongst others, are the main factors.