ABSTRACT
The most part of salt-affected soils of Russia is characterized by subsurface salinity and is mainly found as a part of soil associations consisting of solonetzes (sodic soils) and non-solonetzes. We have produced the approach to digital large-scale soil salinity mapping for such soil regions. The study of spatial distribution of salts on the basis of electrical conductivity measurements in soil samples was conducted in the Yusta district of Kalmykia. The procedure of digital mapping of soil salinity consists of the following stages: (1) automated delineation of nonsaline soils with NDVI values higher than the average in the window of 31 × 31 pixels; (2) calculation of the distance to the nearest nonsaline soil using Proximity grid module of SAGA GIS; (3) the calculation of the function which relates soil salinity and the distance to the nearest nonsaline soil; (4) the prediction of EC values on the basis of this function.
