Aggregate stability of forested soils and badlands areas in the Central Spanish Pyrenees

Abstract

Aggregate stability has been used as an indicator of soil erodibility and ecosystem degradation degree. This paper analyses the aggregate stability in a small catchment, in the Central Spanish Pyrenees, with contrasted land covers (forestry, abandoned fields, meadows and badlands). On this way, the relationships between aggregate stability and some physical and chemical properties of the materials (pH, electrical conductivity, organic matter, carbonates and bulk density) were obtained. The aggregate stability was determined in the laboratory using two different techniques: Drop Test (CND) and Rotations method. The results showed significant differences in agreement with land uses contrasts. Forested area showed higher stability, while loamy regolith presented great fragility and erosive susceptibility. In addition, a direct relationship between moisture raise and aggregate stability has been observed. Also, organic matter and carbonate contents showed a positive effect on aggregate stability. The combination of both methods is favourable for this study, because informed about different components of resistance (splash and transport by overland flow). We suggest the use of the drop-test due to the simple way to apply the test.