The Soil Nutrient Digital Mapping for Precision Agriculture Cases in the Trans-Ural Steppe Zone of Russia Using Topographic Attributes. - Azamat Suleymanov; Evgeny Abakumov; Ruslan S. Suleymanov; Ilyusya Gabbasova; Mikhail A. Komissarov (ISPRS Int. J. Geo Inf., 2021)