Mitigating Aral Sea disaster aftermath: evaluating soil salinization trends and eco-friendly remediation in Karakalpakstan
Abstract
The environmental disaster of the Aral Sea has revealed the Karakalpakstan Autonomous Republic soils to increasing salinity and large-scale degradation. A main contribution of this research is to propose a combined approach (field observation, remote sensing, and remedial experiments) to analyze trends of salinity and evaluate environmentally sound restoration techniques from 2019 to 2024. The results showed that the salinity of the soil (ECe) at 15 km away from the dry lake bed is 35.7 dS/m (±3.2), 4.8 times that of farmland areas distant from the dry lake bed (p<0.001). The dominant ionic constitution of Na+-Cl- (72% of the samples) and high exchangeable sodium percentage (ESP>25%) has reduced the permeability of soil. Seasonal monitoring confirmed the enhancement of summer surface salinity (mean ΔECe=12.7±2.3 dS/m) and salt accumulation at 30-60 cm depths as a long-term problem. The improvement phase saw cultivation of the native plant Tamarix ramosissima, with 92% survival at 28 dS/m, as the most effective method in 58% reduction of surface salinity through physiological means. Its combination with organic mulch (32% decrease in evaporation) and compost (2.3-fold increase in microbial activity) significantly improved soil health. Projections for the future warn of a 67% decrease in wheat production to be expected by 2030, assuming that trends continue, whereas modeling confirms nature-based solutions' effectiveness to stabilize salinity levels at values lower than 20 dS/m. This study specifically emphasizes the need to change wasteful historical practices to ecosystem-based restoration systems as the necessity of quick sustainability of Karakalpakstan.