Abstract Flue gas desulfurization (FGD) gypsum has been widely used and commercialized in some areas to reclaim sodic soil. Previous studies mainly considered the reclamation efficiency after FGD gypsum application, whereas little information is available on the applicable conditions, such as soil moisture. Thus, a pot experiment was conducted with four FGD gypsum application rates (0, 0.5, 1.0 and 1.5% of soil) under four soil moisture conditions (25, 50, 75 and 100% of the water-holding capacity (WHC) at saturation) to investigate the soil salinity and sodicity changes over 90 days. For each moisture condition, the soil pH, sodium adsorption ratio (SAR), exchangeable sodium percentage (ESP) and CO32− and HCO3− concentrations decreased with increasing FGD gypsum application. However, the opposite trend occurred for electrical conductivity (EC) due mainly to the increased soluble cation (i.e., Ca2+, Mg2+, Na+ and K+) and SO42− concentrations. For each FGD gypsum application rate, the soil EC, ESP and Ca2+, Mg2+ and SO42− concentrations decreased while the pH and SAR increased with increasing moisture content. Significant differences in these properties were found mainly between the 0% and 1.5% FGD gypsum application rates or 25% and 100% of WHC moisture conditions. Moreover, the reclamation efficiency caused by soil moisture was concentrated in the first 30 days and gradually decreased with time. Therefore, FGD gypsum can be used to reclaim sodic soil in areas with little water and its effectiveness can be enhanced by moderately increasing its application rate and/or its reaction time with soil.

中文翻译：

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土壤水分对烟气脱硫石膏复垦钠壤的影响

摘要 烟气脱硫（FGD）石膏在一些地区已被广泛应用和商业化，用于复垦钠质土壤。以前的研究主要考虑了 FGD 石膏应用后的复垦效率，而关于适用条件（例如土壤水分）的信息很少。因此，在四种土壤水分条件（25%、50%、75% 和 100% 的饱和持水量（WHC）下，以四种 FGD 石膏施用率（土壤的 0、0.5、1.0 和 1.5%）进行盆栽试验。 ) 调查 90 天内土壤盐度和碱度的变化。对于每种水分条件，土壤 pH 值、钠吸附比 (SAR)、可交换钠百分比 (ESP) 以及 CO32− 和 HCO3− 浓度随着 FGD 石膏施用量的增加而降低。然而，电导率 (EC) 出现相反的趋势，主要是由于可溶性阳离子（即 Ca2+、Mg2+、Na+ 和 K+）和 SO42− 浓度的增加。对于每个 FGD 石膏施用率，土壤 EC、ESP 和 Ca2+、Mg2+ 和 SO42− 浓度降低，而 pH 和 SAR 随水分含量的增加而增加。这些特性的显着差异主要在 0% 和 1.5% 的 FGD 石膏施用率或 25% 和 100% 的 WHC 水分条件之间发现。此外，土壤水分造成的复垦效率集中在前30天，随着时间的推移逐渐下降。因此，FGD石膏可用于在缺水地区回收钠质土壤，适度增加其施用量和/或与土壤的反应时间可以提高其有效性。