Secondary Salinization of Reclaimed Solonetzes and Its Aftereffect

Аннотация

The studies were performed at the long-term stationary experiment on crusty hydromorphic solonetzes of the Baraba Plain during 1986–2017. In the humid year of 2013, the ground water level drastically rose from a depth of 250 cm to 50 cm, and secondary salinization was recorded. The content of soluble salts increased, their composition changed, the soil pH shifted to higher values, and the exchangeable sodium percentage increased. After lowering of the ground water table, salts were gradually washed out from the soil profile in the reclaimed solonetzes, and the positive effect of gypsum was partially restored. The soil adsorption complex was dominated by Mg²⁺ in the control variant and by Ca²⁺ in the reclaimed solonetzes. This phenomenon should be taken into consideration when reclaiming solonetzes, because the positive effect of gypsum application is preserved after secondary salinization.