Development and Application of a Salinity Risk Index for the Red River Valley of the North (MLRA 56).

The Red River Valley is a large highly productive dryland agricultural region in North Dakota, Minnesota, and Manitoba.  Salinity has always been an issue facing producers in this area. However, due to changing cropping systems, increase in lower salt tolerant crops, and two decades of higher precipitation; salinization has become an extremely important economic issue. Soil surveys have identified over one million acres of salt-affected soils.  However, the surveys are dated and have only inventoried saline soils that have adequate crop response to be easily identified in the field.  The Salinity Risk Index (SRI) is a resource inventory model used in Canada and Australia to assess the risk of soil salinity.  Considerable research has been done in MLRA 56 relating soil salinity to hydrology and topography.  This research has shown a strong correlation between discharge sites and salinity in the root zone.  The underlying principle behind the initial phase of the SRI is to model soil hydrology or identify discharge sites using SSURGO and soil classification.   Additional factors include: current salinity status, drainage class, texture, presence of a contrasting layer, and slope.  It is hoped the SRI can quickly and easily identify areas that are saline or have the potential for salinity.  Areas identified as having potential for salinization can then be targeted by conservationists and land managers.