Evaluation of soil salinization in a Mediterranean site (Agoulinitsa district—West Greece)

Abstract

Soil salinization is an environmental problem having significant impacts on the soil–water–plant system. This problem is more frequent in coastal areas due to seawater intrusion into the land. Assessing the soil salinization is a critical issue for the agricultural areas situated in the Mediterranean basin. This paper examines the deterioration of soil quality in the cultivated land of a Mediterranean site (Agoulinitsa district—West Greece). Soil samples were collected in both pre-irrigation and post-irrigation seasons. Electrical conductivity (EC), pH and the ions Br⁻, Ca²⁺, Cl⁻, F⁻, K⁺, Li⁺, Mg²⁺, Na⁺, NH₄ ⁺, NO₂ ⁻, NO₃ ⁻, PO₄ ³⁻ and SO₄ ²⁻ were determined by the 1:2 (soil/water ratio on weight basis) method. The salts which were present in both seasons in the soils of the area studied are KCl, MgCl₂, NaCl, CaSO₄ and K₂SO₄. The wide spatiotemporal variation of EC in the cultivated land in both seasons demonstrates that soil salinity is controlled mainly by seawater intrusion and anthropogenic factors such as the application of salt-rich water which is directly pumped from the drainage ditches. Seawater intrusion provides the affected soil with elevated contents of Ca²⁺, Cl⁻, K⁺, Mg²⁺, Na⁺ and SO₄ ²⁻. Classification of the soils by using criteria given by the literature is discussed. Practices to prevent, or at least ameliorate, salinization in the cultivated land of Agoulinitsa district are proposed.