Comparing Two Saline-Gypseous Wetland Soils in NE Spain

Small (<1 km²) saline wetlands scattered across the landscape often go unnoticed or are threatened by urbanization or other interventions, despite their role as biodiversity shelters. This study is needed to show methods for monitoring this specific kind of wetland, and to guide the selection of analytical techniques. We provide data and comparisons for salient soil traits of two quasi-pristine gypsiferous and saline wetlands named Farrachuela (FA) and Agustín (AG). The soil characteristics presented in this article are a more sensitive indicator of their ecological status than some of the most used indicators, such as birds and plants. We found significant differences between the two saladas in percent water saturation, equivalent calcium carbonate, gypsum content, and soil salinity expressed as electrical conductivity both of 1:5 soil-to-water ratio and of saturation extracts. The differences were also significant in the concentrations of Mg²⁺, Na⁺, and Cl⁻, while they were non-significant for Ca²⁺, HCO₃²⁻, and SO₄²⁻. The mean contents of the six ions were lower in FA than in AG. Both pH and sodium adsorption ratios were significantly different between the two wetlands. The data are mainly examined and plotted by displaying their non-parametric statistics, a synoptic approach that will allow us to monitor the evolution of the wetlands against both traditional agricultural pressures and emerging green energy infrastructures. Last but not least, we discuss the shortcomings of some standard laboratory methods when applied to gypsum-rich soils.