Evaluating soil salinity dynamics under drip irrigation in the Manas River Basin, Xinjiang: a long-term analysis (1996-2019).

The Manas River Basin, located in Xinjiang, China, is one of the province's four major agricultural irrigation regions and the first in the country to implement large-scale drip irrigation. While drip irrigation has enhanced water use efficiency, it has also contributed to soil salinization, negatively impacting crop yields and soil health. This study examines the spatial and temporal evolution of soil salinity in the oasis area of the basin from 1996 to 2019. The study evaluates salinization dynamics under long-term irrigation practices using soil salinity inversion models, regression analysis, water-salt balance calculations, geostatistical techniques, and ArcGIS. The results reveal significant improvements in soil salinity conditions, with 78.02% of the region experiencing reduced salinity and 10.09% exhibiting deterioration. From 1996 to 2019, non-salinized soil increased by 1,403.46 km, mildly salinized soil expanded by 3,702.28 km, while saline soils decreased by 7,685.6 km. Statistical analysis indicates that soil salinity followed normal or logarithmic-normal distributions, with higher variability observed in 2016 and 2019. Despite these positive trends, challenges remain, particularly in the Shihezi, Manas, and Mosuowan irrigation zones, which still exhibit moderate to severe salinity. This study highlights the effectiveness of drip irrigation combined with improved management practices in mitigating soil salinity and enhancing soil quality. However, it emphasizes the need for targeted strategies to address residual salinization risks, ensuring sustainable agricultural development and ecological balance in arid regions.