INFLUENCE OF LONG-TERM CULTIVATION OF RICE ON THE IONIC-SALT COMPOSITION OF AGRICULTURAL SOILS
Sizonenko Karina Ilnurovna - мл. научный сотрудник лаборатории биотехнологии, микробиологии и почвоведения, Astrakhan State University named after V.N. Tatishchev, 414056, Astrakhan, Tatishchev str. , 20a, karina.sizonenko@bk.ru
Khasanova Amina Khanpashaevna - Jr. Researcher at the Laboratory of Biotechnology, Microbiology and Soil Science, Astrakhan State University named after V.N. Tatishchev, Russia, 414056, Astrakhan, Tatishchev str. , 20a,
Fedotova Anna V. - Professor, Doctor of Biological Sciences, chief researcher, head of the laboratory of Forecasting, Bioproductivity of Agroforestry Landscapes, Federal Scientific Center for Agroecology, Integrated Land Reclamation and Protective Forestry of the Russian Academy of Sciences (FSC Agroecology RAS), 400062, Volgograd Universitetskiy Ave., 97, a.v.fedotova@gmail.com
Over the past 20 years, vast areas of fallow lands have formed in the Astrakhan region. Such lands include abandoned rice systems in the Astrakhan region. The history of rice cultivation in the Astrakhan region begins in the 30s of the last century. At the beginning of the 21st century irrigated agriculture in the region fell into decline and gradually led to the destruction of irrigation systems. As a result, the natural process of soil formation began to actively occur in abandoned rice paddies, accompanied by dynamic changes in the morphological and physicochemical properties of soils in rice ecosystems. The salt state of fallow soils was also affected by their diking. The article presents data on the salt state of soils of former rice systems in the Ikryaninsky district in the southwest of the Astrakhan region, within the western periphery of the Volga delta and the eastern edge of the substeppe ilmen. The soils of fallow rice paddies are represented by alluvial turf and desertifying light clay soil. The pH values correspond to a neutral or slightly alkaline reaction of the medium. Salinization is observed from a depth of 30-40 cm (the value of the dense residue is 0,48% -0,64%). The salinity type is chloride-sulfate and changes to sulfate-chloride with depth. The ions in the aqueous extract are dominated by sulfate and chloride ions.
Key words: rice paddies, delta territory, alluvial soils, salinization, fallow lands.
