Climate Change Impacts on Soil Formation and Biotechnological Rehabilitation of Saline Soils in the Dried Aral Sea Seabed

The dried Aral Sea seabed has become one of the most complex newly formed arid landscapes in Central Asia, where climate warming, moisture deficit, wind activity and salt accumulation jointly influence early soil formation and vegetation recovery. The rehabilitation experiment was conducted using control and treatment plots across the same salinity gradient. The biotechnological treatment was evaluated using soil salinity, organic carbon, microbial biomass, vegetation indices, plant survival and soil and vegetation rehabilitation indicators. Between 2021 and 2025, mean air temperature increased from 13.70 to 15.19 °C, annual precipitation declined from 106.33 to 67.84 mm, and evaporation increased from 1,551.81 to 1,739.58 mm. During the same period, mean electrical conductivity increased from 24.59 to 29.35 dS m⁻1, whereas soil moisture, soil organic carbon (SOC), microbial biomass carbon (MBC), normalized difference vegetation index (NDVI) and soil-adjusted vegetation index (SAVI) all declined. During the same period, mean electrical conductivity increased from 24.59 to 29.35 dS m⁻1, soil organic carbon decreased from 2.93 to 2.35 g kg⁻1, microbial biomass carbon declined from 79.41 to 59.72 mg kg⁻1, NDVI decreased from 0.100 to 0.073, and SAVI decreased from 0.232 to 0.184. The strongest degradation was observed in extremely saline soils, where low moisture, high salt concentration and weak biological activity limited natural soil development. In contrast, treated plots showed clear improvement by 2025, with lower electrical conductivity (EC), higher SOC, stronger microbial biomass, better vegetation response and higher plant survival compared with the control. These findings show that the observed warmer, drier and more evaporative conditions were associated with increasing salinity constraints and weaker soil biological functioning during 2021–2025, while biotechnological rehabilitation improved soil and vegetation indicators, particularly under moderate and strong salinity.

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