Desalting effect of flue gas desulfurization gypsum (FGDG) on coastal saline-sodic soil with different textures

摘要

Purpose Soil salinization is a major obstacle to the development and utilization of land resources in coastal areas. The purpose of the study is to explore the desalting effect of flue gas desulfurization gypsum (FGDG) on coastal saline-sodic soils by evaluating changes of soil chemical properties (soluble ions, exchangeable cations, and exchangeable sodium percentage (ESP)), plant growth, and heavy metal contents under field conditions. Materials and methods A 1-year field experiment was carried out in two typical textures of saline-sodic soils in the east China coastal area. The soil textures were silty loam and clay and five rates of FGDG (0, 15, 30, 45, and 60 Mg center dot ha(-1)) were applied to sodic fulvisols (siltic) and spolic technosol (clayic). Results and discussion The experiments showed that the chemical properties were effectively improved by FGDG on the topsoil (0-30 cm) of two different texture saline-sodic soils, and desalting effects (ESP < 15) could be reached within 1 year in different patterns. For sodic fulvisols (siltic), soluble ions, exchangeable cations and ESP linearly changed with FGDG increases, and root length and biomass of Salix integra were increased too. For spolic technosol (clayic), although the chemical indicators and ESP of topsoil could be improved at low FGDG rate, growth of roots was still restricted even at higher FGDG amounts. The experiments also showed that there was no ecological risk of heavy metals for FGDG application. Conclusions FGDG is performed as an eco-friendly amendment for the desalination of coastal saline-sodic soil. An appropriate amount of FGDG application needs to consider soil types and properties.