Impacts of groundwater storage variability on soil salinization in a semi-arid agricultural plain

Soil salinization, which is significantly influenced by groundwater storage dynamics, leads to reduced land productivity, loss of arable land, and degradation of vegetation, thereby posing a substantial threat to global food security and ecosystem functions. The western Songnen Plain (WSP) is one of the world's three largest concentrations of soda saline-alkaline regions. However, the availability of observed data on groundwater storage dynamics in the WSP remains limited, potentially impeding the evaluation of their impacts on soil salinization processes. This study investigated the impact of groundwater storage variability on soil salinization in the WSP, utilizing multi-source satellite data, the Global Land Data Assimilation System hydrological model data, and ground observation data. Our results demonstrated that groundwater storage anomalies (GWSAs) exhibited cyclical fluctuations from 2002 to 2014, followed by a substantial decline of 13.215 cm equivalent water height from 2015 to 2021. GWSAs exhibited a significant positive relationship with the area of medium-salinized soils that comprised over 56 % of the total salinized soil area. Both the area and degree of soil salinization overall decreased in the WSP due to the decline in groundwater storage and the implementation of soil improvement policies. Our results suggest that targeting soil treatment projects on salinized soils that are less affected by groundwater conditions could potentially mitigate soil salinization in the WSP. This study assessed the potential impact of groundwater storage variability on soil salinization, enhancing mechanisms underlying salinization processes and offering valuable data to inform land and water resources management in salinization-prone regions.