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

摘要

A typical chernozem buried under the rampart of the Kama defense line of the Russian Empire in the middle of the 17th century has been studied. The properties of this soil have been compared with the properties of surface chernozems in surrounding landscapes. It is shown that soil properties have not changed much within the past 350 years. However, the downward migration of carbonates has led to a 10 percent 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 seen; it is related to the ascending migration of salts from the parent rock. Both the leaching of carbonates and the accumulation of easily soluble salts can be explained by climatic flucturations during the last four centuries. An original chronological scheme of soil formation during the Holocene is suggested. It includes the prehistoric period, the ancient period, the medieval period, and the recent period.