Analysis of Soil Salinization Induced by Seawater Intrusion on the Coastal Agriculture of Lazio Region (Italy)

In recent years, the coastal areas of the Mediterranean have experienced extreme climatic events, including the intrusion of the salt wedge into freshwater systems. In Italy, this phenomenon is causing an increasing salinisation of coastal agricultural soils. Among these, the Lazio coast, characterized by dune, fluvial-marsh and marine wind deposits, represents a particularly vulnerable area. This territory, historically reclaimed with landfills and drainage, sees agriculture as one of the main socioeconomic drivers. This research aims to evaluate the extent of salinisation in the coastal area around the Tevere River and its potential impact on agriculture. Monitoring was conducted during the 2024 agricultural season through monthly sampling campaigns and measuring soil and surface water parameters. A particular focus was placed on analyzing the salt wedge intrusion in water bodies and in cultivated soils to understand its progression and impacts on crops. Among the techniques used, time domain reflectometry (TDR) proved essential for collecting spatial and temporal data on salt concentration variability. Using TDR both volumetric water content (VWC%) and Electrical conductivity (EC dS/m) were measured, with EC linked soil properties such as water content, texture and organic matter. Additionally, to soil sampling, leaching tests were carried out in the laboratory to assess the release of salts from the soil into water. Preliminary chemical analyses of major ions in the leachates were used to quantify the contribution of soil salinity to water salinization. Monthly soil samples collected from 10 monitoring points showed in several cases salinity levels exceeding the minimum threshold of 2 dS/m indicated by the FAO.  This can adversely affect the growth and yield of various cultivated species. The results highlight the importance of continuous monitoring of parameters such as electrical conductivity, temperature and soil humidity to track salinization trends. Understanding these dynamics is fundamental for developing adaptation and mitigation strategies to preserve the agricultural productivity of the Lazio coast.

Keywords: Lazio Coast, Soil Salinization, Coastal Agriculture, Seawater Intrusion.