In the northern Great Plains, salinity and sodicity are soil landscape related phenomena that have large economic and environmental impacts. Existing soil landscape models provide the general relationship among soils. Salinity and sodicity, however, exhibit spatial (both horizontal and vertical) and temporal variability that is not captured in present soil landscape models. In particular, SAS series concepts reflect Soil Taxonomy threshold values for ESP (13) and SAR (15), but sodium may have negative impacts at lower values (ESP 6). Moreover, the influences of salinity and sodicity may be exacerbated or ameliorated by cultural practices such as deep tillage, cropping practices, and tile drainage. To address these issues we are initiating a multistage project. Our initial goals are: 1.) to spatially link crop yield and productivity data to saline and sodic properties  to obtain a detailed soil landscape models, and 2.) summarize and evaluate existing  soil  characterization, soil morphology,  soil landscapes as they relate to salinity and sodicity.  We will use this information to examine geologic, geochemical, and groundwater (both geochemical and hydro-geological) data available from the Northern Great Plains.  Model soils, geochemistry, and ground water movement within various glaciated and un-glaciated landscapes.  Refine the Salinity Risk Index and extrapolate the design to additional salt-impacted landscapes.