Phytodesalination of a moderately saline soil combined with two inorganic amendments

ABSTRACT 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 (CaSO4·2H2O) 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 + CaSO4·2H2O). Polyvinyl chloride (PVC) tubes filled with 8 kg of clay soil with an electrical conductivity of the saturation paste extract (ECe) of6.21 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). CaSO4·2H2O 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.

摘要 水资源短缺与盐度持续升高是直接影响作物定植与生长发育的核心限制性环境因素。本研究针对中度盐渍化土壤，在温室环境及非淋溶条件下，评估了疣花粟米草（Sesuvium verrucosum）单独施用，以及分别与农用石膏（CaSO₄·2H₂O）、Polisul-C联合施用时的植物脱盐能力。本研究设置如下处理组：T1（纯土壤）、T2（土壤+疣花粟米草）、T3（土壤+疣花粟米草+Polisul-C）、T4（土壤+疣花粟米草+CaSO₄·2H₂O）。实验采用填充8 kg黏壤土的聚氯乙烯（Polyvinyl chloride, PVC）管，供试土壤的饱和泥浆提取液电导率（ECe, electrical conductivity of the saturation paste extract）为6.21 dS·m⁻¹。对土壤样品开展分析，以测定其ECe值与可溶性、可交换性阳离子（Na⁺、K⁺、Ca²⁺、Mg²⁺）含量；随后将盐生植物划分为根系与地上部分，测定其Na⁺、K⁺、Ca²⁺、Mg²⁺含量。综上，疣花粟米草具备对其根际土壤进行脱盐的潜力；当其与任一供试改良剂联合施用时，脱盐能力可显著提升，且该提升主要发生在黏壤土上层（0~30 cm）。农用石膏（CaSO₄·2H₂O）被证实为最有效的改良剂：该化学改良剂可改善土壤理化性质，进而使疣花粟米草获得更高生物量，并促进其地上部分大量积累钠离子（Na⁺）。