Spatial-temporal assessment of soil salinity dynamics in irrigated lands using GIS and remote sensing technologies: A case study of Syrdarya Province, Uzbekistan

Soil salinization represents a critical environmental challenge in arid and semi-arid irrigated agricultural regions, particularly in Central Asia where intensive irrigation practices have led to widespread land degradation. This study investigates the spatial-temporal dynamics of soil salinity in the irrigated lands of Syrdarya Province, Uzbekistan, utilizing an integrated approach combining Geographic Information Systems (GIS), remote sensing technologies, and traditional field measurements. Long-term monitoring data (2004-2024) from 1,500 observation wells and 3,800 soil sampling points were analyzed using Inverse Distance Weighting (IDW) interpolation methods in ArcGIS 10.6. The research examined the relationships between groundwater depth (GWD), groundwater mineralization (GWM), and soil salinity (SS) under changing climatic conditions. Results demonstrated that IDW-based GIS mapping achieved 91.4% accuracy for GWD, 84.1% for GWM, and 76.7% for SS assessment. Statistical analysis revealed strong correlations between shallow groundwater levels (1.0-1.5 m) and increased soil salinity, with GWM exceeding 5-10 g/L significantly contributing to soil degradation. Climate factors, particularly summer air temperature and winter precipitation, showed moderate to strong correlations with salinity distribution patterns. The study identified that approximately 62% of irrigated lands exhibited varying degrees of salinization, with moderately saline soils occupying 32.8% and weakly saline soils 54.9% of total irrigated areas. MODIS satellite thermography and NDVI indices were validated against ground-truth data, demonstrating 70.6% and 81.1% accuracy respectively for salinity assessment. The integration of GIS technologies reduced mapping time by 92.3% and costs by approximately 3,490,140 UZS compared to conventional methods. These findings provide crucial information for sustainable land management strategies and salinity mitigation measures in Central Asian irrigation systems.