Three-dimensional soil salinity mapping for vineyard management in coastal areas of South of France

The aim of this study was to establish a database including mapping of the state of soil degradation due to salinity in a vineyard-growing area of southern France (Domaine de Villeroy, Hérault) and to understand the processes that cause it.The methods are based on direct measurements of soil salinity through sampling and indirect measurements using geophysics (EM38-MK2), measurements of surface and groundwater salinity in order to determine the geochemical signature of the various salinity poles (sea, ponds, canals, surface aquifers), and estimates of aquifer levels (piezometric surveys).The data collected enabled the creation of transects and maps at different depths of the hydro-saline conditions across the entire area between May and July 2024. The mapping was carried out by combining a model based on machine learning methods (Boosting Regression Trees - BRT) of the variables considered and spatialisation with Kriging for the depths 0-20, 20-40, 40-60, 60-80, 80-100, and 100-120 cm. A corresponding estimate of the impact of salinity on the current vegetative development of the vine was made on the basis of aerial images and direct observations of plant vigour and plant mortality.