Abstract
Prolonged flooding of paddy fields exceeding 60–80 days triggers water-bogging, gleying of the soil profile, and a reduction in total soil porosity by at least 25–30%. The article addresses the challenges associated with the reclamation state of rice irrigation systems in the Kyzylorda region. The study aims to scientifically substantiate the optimal parameters for groundwater table depth and mineralization to prevent irrigation-induced salinization and effectively restore soil fertility. Field and laboratory experiments were carried out in 2022–2023 at the Karaultobe experimental site covering an area of 16 hectares. The research methodology involved stationary water level monitoring, systematic hydrochemical sampling, and phenological observations of plant development. It was established that during the initial flooding phase, pore water salinity in the arable layer sharply increases to 3.2–6.5 g/L. This induces seedling suppression, reduces stand density to 80–120 plants per square meter, and results in an average yield drop of 1.6 t/ha. Lowering the groundwater level to 1.8–2.0 m within 20–25 days during the irrigation interval restores proper soil aeration and increases rice yield to 4.0–5.0 t/ha. These findings justify the need to regulate the initial irrigation modules and transition toward subsurface horizontal drainage construction.