Modern state of soil salinity in solonetzic soil complexes at the Dzhanybek Research Station in the North Caspian Region

Abstract

Variations in the salinity of virgin soils of solonetzic soil complexes at the Dzhanybek Research Station are characterized on the basis of field materials obtained by the author in 2002–2004. The soil salinity is characterized with respect to the depth of the upper boundary of salt-bearing horizons, the total amount of salts, the content of toxic salts, and the chemical composition of salts. Changes in the soil salinity under dry farming conditions are estimated for the following soil management practices: (1) agroforest amelioration with additional moistening of virgin soils owing to snow retention by the adjacent shelterbelts and forest plantations, (2) intense grazing, (3) soil fallowing after normal tillage to a depth of 20–25 cm, and (4) soil fallowing after deep tillage to a depth of 40–50 cm. It is shown that normal tillage and considerable grazing pressure do not affect the salinity of the studied soils. No definite effect of the shelterbelts on the salt status of the adjacent virgin soils of the solonetzic complex has been revealed. Deep soil tillage strongly affects the salt status of solonetzes: the content of toxic salts in the upper meter considerably decreases. Virgin solonetzes are usually moderately or strongly saline soils, whereas deeply tilled solonetzes are slightly or moderately saline soils.