COMBINATION OF SALINE SOILS OF THE NORTHERN SLOPE OF THE ERGENI UPLAND AFTER IRRIGATION CESSATION

Abstract

The soil cover and soil salinity of the field were studied and the results are given in the article, the explored fileld is located within the Chervlenoye irrigated area belonging to Svetloyarskaya irrigation system (south of the Volgograd region). It was characterized by alternating dark and light wide strips visible on the satellite image. The field was irrigated until the mid-1990s and was subject to secondary salinization, since that time it has been used in dry-farming system. The soil combination is performed by steppe light chestnut solonetzic complex that was transformed due to the surface leveling and irrigation into agrozem accumulative-carbonate segregation saline (Sodic Endoprotosalic Cambisol (Loamic, Aric, Protocalcic, Ochric, Bathygypsic) and Cambic Calcisols (Loamic, Aric)) and deep saline, and agro-light-humus accumulative-carbonate stratified soil. The bright bands on the field mark soils rich in carbonates on the surface (12–13 % CaCO3) (Calcaric Cambisol (Loamic, Aric)) among the other soils that contain less carbonates on the surface by 5–10 times. All the soils are saline, but the salt content varies in space in a wave-like manner, wich disagrees with the satellite image. Two-dimensional distributions of carbonates and salts in the soil combination are discussed. The residual signs of secondary salinization are revealed in the form of calcium and magnesium chlorides two decades after the cessation of irrigation and drawdown of the groundwater curve deeper than 7 m.

Keywords

• carbonates
• saline soils
• water extraction
• ion-selective electrodes
• ions activity