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

Usually, soils changed by farming (agrogenic soils) are not shown on small-scale maps, including the Soil Map of the Russian Federation, 1 : 2.5 M scale (1988). One of the issues of the map updating performed by the Dokuchaev Soil Science Institute is the inclusion 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 agrosoils in different orders and as 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 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 agrosoils and agrozems have been identified. This number is dictated by the diversity of native soils subjected to the agrogenic impact and their agrogenic modifications. Agrogenic soils on the updated map are shown in 4813 polygons out of the total of 25711 map polygons. Chernozems are characterized by the greatest diversity of agrosoils and the largest number of polygons containing various agrochernozems. The order of texture-differentiated soils is also rich in agrogenic soils, both agrosoils 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 only represented by Al–Fe-humus agrozems. The number of polygons with participation of agrogenic soils and their proportion in the soil cover illustrate geographical patterns of their distribution, in particular, homogenous or mosaic distribution patterns in the areas of different soil orders.