Ultrasound-assisted soil reclamation: a rapid method for removing sodium ions from saline-sodic soils

Saline-sodic soils are a significant barrier to sustainable agriculture, requiring time-consuming and costly reclamation methods. This study evaluates ultrasound-assisted washing as a novel technique to address this challenge. Utilizing ultrasonic waves (20 kHz), the method induces cavitation, facilitating the detachment of exchangeable sodium ions from soil particles and enhancing their mobility. Experiments were conducted on highly saline-sodic soil (pHs: 10.34, ECe: 32.08 dS m⁻¹, and ESP: 68.16%) using varying ultrasound amplitudes (10–100%) and durations (1–60 min). Results demonstrated substantial reductions in pHs, ECe, and ESP, with up to 43.26% sodium removal confirmed by SEM and EDX analyses. The treatment also induced structural changes, including increased surface area and reduced particle aggregation. Although the ESP target (< 15%) was not fully achieved, the findings highlight the potential of ultrasound-assisted washing as an effective and sustainable alternative to conventional methods. This study contributes to global efforts to combat soil salinity and sodicity by introducing a novel, technology-driven solution that aligns with the Sustainable Development Goals for mitigating land degradation and enhancing agricultural resilience.