From Irrigation Stability to Aridification: War-Induced Transformation of Irrigated Agroecosystems in Southern Ukraine

Abstract The study assesses spatio-temporal patterns of transition from irrigation stability to aridification of agricultural landscapes in Southern Ukraine due to war-induced destruction of water infrastructure and increased climate extremes. The subject of analysis is the irrigated area in the Kherson region, whose functioning depended on the Kakhovka Reservoir’s resources until 2023. The research methodology is based on the integrated use of the Soil Water Index (SWI) and Terrestrial Chlorophyll Index (OTCI) from satellite observations, analysis of temperature and hydrothermal indices, and assessment of yield trends between 2021 and 2025. A cascading degradation mechanism was observed: the loss of water-regulating function after the Kakhovka Dam’s destruction in 2023 and the Reservoir’s drainage have caused the depletion of productive soil moisture, a decline in plant photosynthetic activity, increased heat and drought stress, and a sharp drop in crop productivity. SWI trends indicated transition from largely satisfactory moisture levels in 2021 to prevalent high or critical water stress between 2024 and 2025. The synchronous decrease in the OTCI confirmed vegetation cover degradation. The index peak values decreased more than twofold, which corresponds to the transition from highly productive irrigated agrocenoses to degradation with signs of soil drought. The findings demonstrate a synergistic effect of war-induced and climate-related factors, which have created preconditions for the region’s long-term aridification. The study substantiates the necessity of restoring water management and devising adaptive strategies for postwar irrigation rehabilitation as a key factor in rebuilding the bioclimatic resilience of Southern Ukraine.