Anthropogenic Evolution of Zheltozems in Sochi Sanatorium Area
The anthropogenic evolution of zheltozems (Acrisols) in the sanatorium zone of Sochi agglomeration since the late 20-ies of the last century is characterized by a change in the acid-base properties and humus state of soils. The pHwater shifted from 5.1 to 7.4 (average values for the genetic horizons of soils), the exchangeable bases increased 2.4 times in the upper horizon (from 17.2 to 41.2 cmolс/kg) and 1.3 times (from 15.9 to 21.0 cmolс/kg) in the structural-metamorphic gleyic BMg horizon. Soil alkalization, typical of urban environments, determined the suppression of eluvial processes in the upper part of BMg horizon. Humus content in the topsoils remained at the same level (about 6.7%), but it increased in the subsoils (up to 3.6–4.3% versus the initial 0.5–0.8%). This transformation is caused by two reasons: 1) input of technogenic salts (with surface runoff and drainage water), which are known to be alkaline and transforming the acid-base soil properties; 2) cultivation of soils (putting on the soil surface the material of the humus horizon of chernozems) for exotic plants of dendroparks in sanatoriums, which changed the soil humus state. Soils are qualified for dark structural-metamorphic agrozems. Locally, abrazems occur, on the lower sections of slopes adjacent to the channels of small streams, there are chemozems over zheltozems. On the steep slopes to the Black Sea, under natural vegetation, typical zheltozems are developed.