Factors and mechanisms of soil salinization under vineyards of southern Taman

Abstract

The spatial distribution of saline soils under vineyards in the south of Taman Peninsular is discussed. The Paleogene–Neogene clays of the Komendantskaya Mount serve as the source of salts. Vineyards were planted on an inclined plain at the foot of this mount. At present, their state on salt-affected soils worsens. In the upper part of the plain, solonchakous or deep-solonchakous slightly saline and nonsaline (within the upper 2 m) dark quasigley vertic soils (Vertisols) are formed. The salts are of the sulfate–sodium composition. Their vertical distribution has an eluvial pattern with a quick rise in the salt content from the surface layer to the depth of 50–100 cm and with a gradual increase in the salt content in the deeper layers. The absence of chlorides in the soils of flat areas within the slope attests to the predominance of lateral leaching of salts down the slope over their vertical leaching in the soil profiles. In the lower part of the slope, soil salinization mainly takes place in the hollow crossing the plain and the vineyard from the north to the south. In the middle part of the slope, nonsaline (to a depth of 2 m) agrohumus quasigley soils (Haplic Chernozems (Clayic, Aric, Stagnic)) are formed. Slight chloride–sulfate sodium salinization is only seen in the soils of the hollow, which contain fine-crystalline gypsum in the solid phase and display the accumulation of sodium chlorides in the middle part of the soil profile (in the 60–150-cm-thick layer). Heavy loamy agrochernozems with migrational and segregational forms of carbonates (Haplic Chernozems (Loamic, Aric, Pachic) are developed in the lower part of the slope; they are nonsaline to the depth of 2.5 m. In the area of transition from the humusquasigley soils to chernozems, specific horizons are formed in the hollow at the depth of more than 250 cm. Their soil solutions contain sodium, calcium, and magnesium chlorides against the background of the presence of fine-crystalline gypsum in the solid phase, which is typical of secondary salinization.