Analysis of Irrigated Salt-Affected Soils in the Central Fergana Valley, Uzbekistan, Using Landsat 8 and Sentinel-2 Satellite Images, Laboratory Studies, and Spectral Index-Based Approaches

Soil salinity is a fundamental barrier to soil fertility, particularly in dry climates, and is a limiting factor for agricultural output and subterranean water utilization. Soil salinity significantly restricts agricultural soils in Uzbekistan. Remote sensing and satellite images were used to evaluate soil salinity in the Mingbulak District of Uzbekistan. In October 2019, soil samples were taken from various locations and analyzed, and soil salinity indices were calculated. The region’s soil salinity was then mapped and modeled. The results revealed that SI 12 and the NDSI from Landsat 8 were superior to the others. The accuracy of the single band B2 and that of salinity indices SI1 and SI8 of Landsat 8 and Sentinel-2A were higher in the deeper layers than in the upper. NDSI was used to model the relationship between soil salinity (electrical conductivity) and the prominent salt ion SO_4^2 - . The model was validated successfully, and a soil salinity map was created. According to the findings, the NDSI provided more accurate information on soil salinity than the other salinity indices, and the blue band was successful in depicting sublayers and the overall salinity of the region.