Assessment of soil salinity in hot humid coastal ecoregion of Konkan zone Raigad district of Maharashtra India

Coastal soil salinization driven by sea-level rise and changing climate patterns is a serious threat to agricultural productivity and wetland ecosystems worldwide. This study evaluated temporal variations in soil salinity across seven coastal locations, namely low saline (Sites 6 and 7), moderately saline (Site 3), very saline (Sites 4 and 5), and strongly saline (Sites 1 and 2). Monthly topsoil samples (0–15 cm) were collected from May 2024 to April 2025 using GPS to assess climate-induced processes influencing salt accumulation, leaching, and redistribution. Soil pH of soil saturation paste (pHe) extract ranged from slightly acidic (6.58) to moderately alkaline (8.49), while the electrical conductivity of soil saturation paste extract (ECe) varied from 5.68 to 65.29 dS m –1 , with peak salinity observed during dry months across all the sites. Elevated concentrations of soluble sodium and chloride ions in very saline and strongly saline sites showed significant intrusion of creek water. There was a higher content of potassium, calcium, magnesium, chloride, sulphate, carbonate, and bicarbonate during dry periods, whereas wet seasons promoted salt leaching and reduced Na⁺ levels. Principal Component Analysis (PCA) showed that PC1 explained 38% of the overall variance (eigenvalue 8.36), which was associated strongly with ECe, exchangeable sodium, calcium, exchangeable sodium percentage, sodium adsorption ratio, water-soluble potassium, calcium, magnesium, chloride, sulphur and available sulphur, and described the major salinity variation. However, rainfall, pHe, exchangeable potassium, water-soluble exchangeable percentage, and sodium adsorption ratio showed strong negative loadings, highlighting their major role in salinization dynamics. Spearman’s correlation confirmed that rainfall showed negative relationship with ECe and soluble salts because of leaching, whereas higher temperatures increased salinity through evaporation. These results provide a scientific basis for a management approach tailored to particular sites, such as salt-tolerant crops, enhanced drainage, residues management, and organic amendments, to support the resilience of coastal agro-ecosystems within varying climatic environments.