Effects of redistribution processes on rock fragment variability within a vineyard topsoil in Mediterranean France

In Mediterranean vineyard landscapes, to understand soil cover evolution at the landscape scale via soil redistribution, one must take into account soil and land use specificities. Soils are characterised by large quantities of rock fragments, and affect hydrological and erosion processes that have widely been published in the literature. Vineyards require a persistent cultivation pattern, and soil tillage operations can often affect vertical and lateral rock fragment distribution. The aim of this study is to analyse rock fragment content and variability in the topsoil (0–15 cm) of a Mediterranean vineyard to determine whether rock fragment distribution (2–64 mm) at a farm plot is influenced by soil type and/or linked to environmental parameters. Furthermore, relationships between observed rock fragment distribution, tillage and water erosion processes are discussed. The field survey was based on a stratified sampling strategy, taking into account soil type, cultivation patterns and farm plot topography. The results suggest that the effect of cultivation in the row/inter-row system is more pronounced than the previously inferred topographic effect. The long-term vineyard cultivation pattern induces spatial segregation of redistribution processes, with cumulative effects over several years that are responsible for rock fragment spatial variability in topsoil.