Landscape-ecological assessment and meliorative status of the Shohimardonsoy River basin, Fergana Valley, Uzbekistan

This study presents a comprehensive landscape-ecological assessment of the Shohimardonsoy River basin in the Fergana Valley, Uzbekistan, focusing on meliorative conditions and geoecological status over the period 2013-2023. Using integrated field surveys, GIS technologies, and mathematical modeling, we identified 16 distinct landscape types across altitudinal zones from 4,500m to 500m elevation. Water chemistry analysis revealed systematic downstream mineralization increase from 0.143 g/dm³ in pristine mountain tributaries to 0.265 g/dm³ in lower reaches, with detection of antimony isotopes [(6.3±0.608) × 10⁴] linked to upstream mining activities. Soil salinity assessment demonstrated remarkable improvement across the basin, with salinized areas decreasing by 47-79% in different districts, from 45,273 ha (2013) to 17,387 ha (2023). Meliorative conditions improved significantly, with lands classified as "Good" increasing from 28-96% to 72-98% depending on location. Mathematical modeling using Poisson distribution established quantitative relationships between elevation, flow velocity (3.9-14.2 m³/s), and sediment composition. The integrated geoecological assessment categorized 38% of the basin as "Satisfactory," 41% as "Moderately Tense," and 21% requiring intervention. The study provides detailed landscape-typological, meliorative, and geoecological maps at 1:350,000 scale, offering a scientific framework for sustainable basin management and supporting policy development for water resource conservation in Central Asian mountain-fed river systems.