Understanding the relationship between the application of soil conditioners and soil quality is crucial for achieving sustainably high crop yields and the remediation of saline-alkali soils in agricultural systems. However, to date, there have been few reports on the use of soil quality index (SQI) to characterize soil quality restoration in different soil layers of saline alkali land. We conducted a field experiment over three growing seasons (2022 – 2024) and collected soil samples after soybe