Effects of continuous application flue-gas desulfurization gypsum and brackish ice on soil chemical properties and maize growth in a saline soil in coastal area of China

Abstract

The reclamation potential of applying combined brackish ice and flue-gas desulfurization (FGD) gypsum to a coastal saline soil was evaluated in a raised bed agroecosystem. Experimental plots in the raised bed were exposed to the following six treatments: 0, 4,000, and 8,000 m 3 ha −1 brackish ice mulch with and without FGD-gypsum. Although FGD-gypsum incorporation still increased the electrical conductivity of a saturated soil paste extract (EC e ) in the 0–20 cm soil layer after brackish ice melted in the second year (April 2013), they had not increased soil EC e at harvest especially in the second year. FGD-gypsum incorporation reduced soil pH not only after brackish ice melted in the second year but also at harvest in the first and second years. At harvest in the second year, FGD-gypsum incorporation significantly decreased soil Na adsorption ration (SAR) of the 0–20 cm layer with different volumes of brackish ice compared with the treatments without FGD-gypsum. The incorporation of FGD-gypsum increased the root dry weight per plant compared with the treatment without FGD-gypsum after harvest in the first year. The incorporation of FGD-gypsum increased organic matter in the 0–20 cm soil layer in the raised bed after harvest only in the first year. The application of brackish ice increased the emergence rate of maize in spring. Soil pH in all treatments tended to increase as time increased in the 0–20 and 20–40 cm soil layers in the raised bed. The results of the present study suggest that brackish ice and FGD-gypsum application further improve soil properties and crop growth, which might accelerate the reclamation process of the coastal saline land.