Buried soils of defense lines of ancient Russia and the problems of ancient and recent history of soil formation

A typical chernozem buried under the rampart of the Kama defense line of th e Russian Empire in the middle of the 17th century has been studied. The pr operties of this soil have been compared with the properties of surface che rnozems in surrounding landscapes. It is shown that soil properties have no t changed much within the past 350 years. However, the downward migration o f carbonates has led to a 10% decrease in the total pool of soil carbonates within the 2-m-thick layer. At the same time, a tendency for accumulation of easily soluble salts and gypsum in the 100- to 200-cm layer is clearly s een; it is related to the ascending migration of salts from the parent rock . Both the leaching of carbonates and the accumulation of easily soluble sa lts can be explained by climatic fluctuations during the last three-four ce nturies. An original chronological scheme of soil formation during the Holo cene is suggested. It includes the prehistoric period (12-5 ka BP), the anc ient period (from the third millennium BC to the fourth century AD), the me dieval period (from the fifth to the 16th century AD), and the recent perio d (the last 300-400 years).