Phytodesalination of a moderately saline soil combined with two inorganic amendments

The shortage of water and the increasing salinity are the main limiting environmental factors that directly affect the establishment and the development of crops. In this research, phytodesalination capacity of Sesuvium verrucosum was evaluated alone and in combination with agricultural gypsum (CaSO₄·2H₂ O) and Polisul-C, in order to remedy a moderately saline soil at greenhouse level and under nonleaching conditions. The treatments studied were the following: T1 (soil), T2 (soil + S. verrucosum), T3 (soil + S. verrucosum + Polisul-C), T4 (soil + S. verrucosum + CaSO₄·2H₂ O). Polyvinyl chloride (PVC) tubes filled with 8 kg of clay soil with an electrical conductivity of the saturation paste extract (ECe) of 6.21 dS.m^-1 were used. Soil samples were analyzed to determine the ECe, and the soluble and interchangeable cations (Na⁺, K⁺, Ca²⁺ and Mg²⁺) content. Then, the halophytic plants were divided into root and aerial parts and the content of Na⁺, K⁺, Ca²⁺ and Mg²⁺ was determined. In summary, S. verrucosum showed potential to desalinate its rhizosphere. Moreover, S. verrucosum desalination capacity significantly increases when used in combination with either of the tested amendments. This increase occurred mainly in the upper layers of the clay soil (0-30 cm). CaSO₄·2H₂ O was shown to be the most effective amendment, since a greater gain in biomass and a large accumulation of sodium (Na⁺) in the aerial part of S. verrucosum was observed as a consequence of the soil improved physico-chemical properties caused by this chemical.