The aim of the research is to study the impact of chemical amendments on the operation of horizontal drainage during leaching of low-permeable clay saline soils and determine the efficiency of leaching. The object under study is clay soil in Azerbaijan's Shirvan steppe, which is characterized by low water permeability and high salinity. The type of soil salinization is chloride-sulfate. There were four variants in the experiment: leaching by plain water without chemical amendment; leaching after saturating soil layer 0–100 cm by 0.5% solution of waste hydrochloric acid; leaching after saturating soil layer 0–100 cm by 1.0% solution of waste sulfuric acid; leaching after applying iron cinder together with concentrated sulfuric acid by the ratio 1:0.3. Analysis of the research results has shown that in the variant with 0.5% solution of waste hydrochloric acid the module of drainage flow was 0.435 l/(sec•ha). That is roughly two times greater than in the control variant. While leaching by 1.0% solution of waste sulfuric acid, module of drainage flow was approximately three times greater comparing to the leaching by plain water. Leaching with iron cinder applying together with concentrated sulfuric acid by the ratio 1:0.3 provided the module of drainage flow 1.6 times greater than leaching using plain water. It was noted that in the beginning of leaching drainage water salinity in variants studied varied from 54 to 320 g/dm³, and in the control variant – from 37 to 158 g/dm³. At the end of leaching, drainage water salinity decreased to 30–32 g/dm³ in all variants.
Keywords: chemical amendment, leaching, drainage, module of drainage flow, waste acid, solution, water permeability, clay soil, salinization.
