Soils of Ancient Agricultural Terraces of the Eastern Caucasus

Abstract

The morphological and chemical properties and biological activity of soils on ancient agricultural terraces in the middle-high mountains of the Eastern Caucasus are considered. The studied terraces were constructed on sandstone, limestone, clay shale, and colluvium of clay and sandstone. The properties of soils formed on these terraces are determined by the properties of soil-forming rocks, as well as by the duration and intensity of human activity. The more favorable for agricultural development the initial soils, the longer and stronger their anthropogenic transformation. Diagnostic features inherent to all lithological varieties of mountainous anthropogenic soils of the Eastern Caucasus and features characteristic of soils developed on the particular types of soil-forming rocks have been identified. The most important diagnostic feature of the soil cover on agricultural terraces is the regular replacement of agrolithozems in the rear parts of the terraces with dark-humus stratozems in their front parts, near the terrace brows. Also, a common diagnostic feature for all soils of terraces is the presence of gravels (up to 3–5 cm in size) evenly distributed throughout the arable layer. Additions to the classification system of Russian soils have been proposed. The soils of human-made agricultural terraces should be classified as a new subtype in the type of stratozems. The proposed subtype name—agristratified soil (or Terrasozem)—reflects the mechanism of the development of stratified soil thickness, i.e., the long-term agricultural impact (agristratified soil, ast). The results of our study can be used in the assessment of the potential for agricultural use of soils in the Eastern Caucasus.