Saline Soils - What's the Remedy?

Recently in a Cropping Systems class discussion, the topic of saline soils came up. Saline soils, as defined by Dr. David Franzen in an NDSU Extension Bulletin titled Managing Saline Soils in North Dakota, are soils that "have salt levels high enough that either crop yields begin to suffer or cropping is impractical."

Saline soil in Western North Dakota - affected soil is white

Salinity is of great concern for North Dakota agriculturalists. Across the state, about 8,700,000 acres are affected by salinity that limits the growth of plants. 

Although it would be pertinent to get into detail and explain how salinity negatively effects plants and why it is cause for such concern, that is not the reason I am writing this blog post. To learn more about how salinity effects plants and why it is an issue in ND, I would recommend watching this half hour documentary on Soil Salinity in ND called Salt of the Earth. 

The reason I am writing is to discuss strategies to manage saline soil. There is no short term solution and managing this problem isn't easy.

Before I go into what will work, I want to briefly touch on what WON'T work. 

Managing saline soils as SODIC soils, will not work. Sodic soils are soils which are affected by high levels of sodium and exhibit the negative effects of dispersion which cause massive soil structure (or lack of, which prevents water infiltration and causes severe crusting when dry) and water ponding.

Sodic and Saline soils are not the same and must not be treated as such. 

With that being said, adding lime (CaCO3) or gypsum (CaSO4) to manage saline soil will NOT work. While both materials are used to manage sodic soils, neither will help to manage saline soils. Again, saline soils are soils affected by an excess amount of salts, such as calcium sulfate, magnesium sulfate and sodium sulfate. Adding more salts (lime and gypsum) will not help in managing saline soils. 

Now on to what will work.

According to the aforementioned Extension Bulletin from Dr. Franzen, soil salinity can be managed through: 

• Tile drainage
• No-till or reduced/minimum tillage
• Selecting crop varieties based on tolerance to salinity
• Seeding in saline areas when salinity levels are lowest (from snowmelt or spring rains)
• Not fallowing (fallow means to leave an area bare, or without a crop for an extended period of time to build up moisture; bare soil can accentuate a salinity problem)
• Using crops with long roots and long growing seasons to control ground water depth

Salinity problems don't go away after one growing season. They aren't easy to deal with and they are here for the long haul.