Agrogenic Soils on the Updated Version of the Soil Map of Russia, 1 : 2.5 M Scale: Classification Diversity and Position in the Soil Cover

Abstract— Usually, soils changed by farming (agrogenic soils) are not shown on small-scale maps, the Soil Map of the Russian Federation, 1 : 2.5 M scale (1988), in particular. One of the issues of the map updating performed in the Dokuchaev Soil Science Institute is the introduction of agrogenic soils into the map contents and representation of some of the former native soils as agrogenic soils on the updated map. Preliminarily, all native soils shown on the map have been reclassified into the new Russian soil classification system. Agrogenic soils in this system are separated as agro-soils in different orders and form a specific order of agrozems. Agrogenic soils have been identified in the soil polygons in agreement with the map showing the percentage of arable land in Russia as determined by I.Yu. Savin with coauthors (2020) and linked to the polygons of the soil map. We have identified the classification position of the initial native soils involved in arable farming. Overall, 114 legend units representing agro-soils and agrozems have been identified. This number is dictated by the diversity of native soils subjected to the agricultural impact producing their agrogenic modifications. Agrogenic soils on the updated map are shown in 4813 polygons out of the total of 25 711 polygons. Chernozems are characterized by the greatest diversity of agro-soils and the largest number of polygons containing diverse agro-chernozems. The order of texture-differentiated soils is also rich in agrogenic soils, both agro-soils and agrozems. Arable soils initially belonging to the order of Al–Fe-humus soils are present in a relatively small number of polygons and are represented only by Al–Fe-humus agrozems. The number of polygons with participation of agrogenic soils and their proportion in the soil cover illustrates the geographical pattern of their distribution, in particular, homogenous or mosaic patterns in the areas of different soil orders.