Ameliorative status of irrigated soils in Rostov oblast

The development of irrigation and the ameliorative status of irrigated lands in Rostov oblast are analyzed for a fifty-year-long period (1952–2001). Three stages of irrigation development are specified. The first stage (1952–1982) was characterized by poor operating conditions of irrigated lands. The second stage (1982–1990) was a period of the most intense irrigation and improvement of the ameliorative status of irrigated lands. The third period (1990–2001) was marked by a drop in the area of irrigated lands and exclusion of lands with unsatisfactory ameliorative status from irrigation. The natural and operating conditions of 18 irrigation systems allocated to areas with different lithological and geomorphic features and soils (chernozems, dark chestnut, meadow, alluvial, and other soils) are characterized. It is shown that soil irrigation often leads to the development of negative soil processes, such as salinization, alkalization, and waterlogging. They are related to the natural and operating conditions of irrigated systems. Secondary salinization and waterlogging are most active in irrigation systems used for rice growing independently of the natural conditions. Upon initially weak salinization of soils and rocks, secondary salinization and alkalization are slightly developed. In the secondary saline and solonetzic soils excluded from irrigation, residual solonetzic features are preserved for more than 15–20 years.