The impact of vegetation on the stability of dispersive material forming biancane badlands in Val d'Orcia, Tuscany, Central Italy

• We sampled and examined a typical biancana in Val d'Orcia, Tuscany
• Physical and chemical parameters were analyzed, such as grain size, ESP and OM
• Sampled areas within the biancana were divided in vegetated, bare and transition
• Physicochemical parameters, especially ESP and OM vary in the different areas
• The presence of vegetation seems to decrease the soil erodibility of the biancana

The landscape of the Val d'Orcia is characterized by biancane badlands that have begun to be overgrown with vegetation in recent years, thus causing a loss of the landscape's biodiversity and cultural significance. The aim of this paper is to examine the role of vegetation and associated soil properties on the erodibility and stability of biancane badlands. We attempt to identify factors that clearly distinguish the bare slope area, where erosion is particularly strong, from the vegetated slope area of a typical biancana in the Val d'Orcia. The data indicate that the vegetated area is characterized by decreased percentages of exchangeable Na+ resulting in a less dispersive character of the soil material in comparison to the bare area. Furthermore, the vegetated area exhibits an increased organic matter content and enhanced water infiltration. Changes in soil properties are probably due to the presence of a continuous vegetation cover that enhances organic matter accumulation, water infiltration, sodium leaching and subsequently soil development. It is concluded that vegetation plays a crucial role in altering soil properties to form more stable slope conditions.