Developing a Spatial Soil Database with Environmental Variables: Experience of the Republic of Bashkortostan

The aim of this work is to create and harmonize a spatial soil database with environmental variables (covariates) for the Republic of Bashkortostan (Russia). The database was compiled using data from field surveys, reports, scientific publications, and existing databases. The largest sample of soil parameters included pHKCl, Corg, and nutrients content, and the thickness of the humus-accumulative horizon. Of those, the most extensive data were obtained for pHKCl and Corg, comprising 32 144 and 29 491 measurements, respectively. For the republic, 82 spatial variables were selected and harmonized, reflecting the main soil-forming factors. This database is fully ready for data-driven research, including processing and modeling using artificial intelligence techniques. One of the main constraints is the insufficient amount of data from mountain landscapes, highlighting the need for further soil data collection in these areas. The results presented for Bashkortostan can serve as a starting point for developing regional soil databases and collecting spatial environmental information.