Quantifying soil volume changes in vineyards: a study of expansive clay soils in Oltrepò Pavese

Soils rich in expansive clay minerals undergo significant soil structures and volume changes due to moisture fluctuations, swelling when absorbing water and shrinking as they dry. The volume changes can lead to structural damage in buildings and land degradation, and cause the formation of deep, polygonal cracks on the surface during dry periods. This affects water retention, infiltration, and root development, and leads to issues in hydrological modelling since the soil's response to water content changes is nonlinear and site-specific.
The aim of the study is to quantify soil volume changes by combining field measurements (soil water content) with laboratory analysis (HYPROP), correlating soil water content with volume changes over time at different soil depths. The time series of volume changes are then compared with Advanced Differential Interferometric Synthetic Aperture Radar (A-DInSAR) displacement time series.
The study focuses on Oltrepò Pavese, an agricultural area and one of the largest wine-producing regions in Lombardy, northwestern Italy. In this area, a monitoring system comprising meteorological and hydrological probes has been installed in the soil since 2021 as part of the Drive Life project (https://www.drive-life.it/) and now it is managed in the framework of the NODES project, financed by MUR – M4C2 1.5 of PNRR, funded by the European Union's NextGenerationEU (Grant agreement no. ECS00000036).
The quantification of the soil volume changes under varying soil water contents can enhance the accuracy of hydrological models.