Effects of different amendments on soil physical and chemical properties and wheat growth in a coastal saline soil

ObjectivesSalt stress is one of the main limiting factors to improve grain yield in the coastal saline soil. Studying the effects of different functional modified materials on the elimination and mitigation of this limiting factor can provide theoretical basis for the amendment of saline soil and the improvement of crop yield.

MethodsWheat cultivar ‘Qingmai 6’ was used as tested materials in coastal saline soil. The study included 7 experiments, blank control (CK), phosphogypsum (PG), flue gas desulfurization gypsum (FGD) containing calcium materials, ferrous sulfate (FS) of acidic material, cattle manure (M) containing carbon materials, humic acid (HA) and furfural residue (FRs) of acidic material containing carbon. We analyzed and compared the impacts of different amendments on the coastal saline soil physicochemical properties and growth of wheat.

ResultsThe amendments could reduce the pH values of surface soil (0–20 cm), especially the acid materials (HA, FRs and FS) significantly lowered the pH of the soil by 0.10, 0.11 and 0.11 compared with the control. The exchangeable sodium ion contents and the sodium adsorption ratio (SAR) values were significantly decreased by applying the PG and FGD in the 0–20 cm, 20–40 cm and 40–60 cm soil layers, due to a large amount of calcium ion to replace the exchangeable sodium in soil. Compared with control, PG significantly decreased the exchangeable Na⁺ contents and the SAR values by 15.5% and 18.3% (0–20 cm), 28.2% and 28.6% (20–40 cm), 36.5% and 36.5% (40–60 cm), and the FGD decreased the exchangeable Na⁺ contents and the SAR values by 24.9% and 27.9% (0–20 cm), 27.6% and 26.3% (20–40 cm), 24.5% and 25.0% (40–60 cm) respectively; the PG, FGD and FRs significantly increased the grain yields by 26.7%, 17.8% and 17.8% and increased the spike numbers by 27.6%, 24.5% and 18.6%, respectively.

ConclusionsThe HA, FRs and FS of acidic materials can obviously reduce soil pH value and increase the number of tillers at the seedling stage of wheat. Considering the effects of amendments on soil pH, Na⁺ content, SAR value and spike number of wheat, the furfural residue of acidic materials containing carbon was better. The PG and FGD containing calcium materials can significantly reduce soil Na⁺ content and SAR value, increase spike number of wheat at maturity stage and improve wheat yield, and the PG treatment have the best effect .