Subsoil EC Soil Mapping

Subsoil EC looks deep into the soil profile to measure the depth of coal seams, overburden on gravel deposits and so on. In agriculture there are times when it is beneficial to know subsoil properties. One critical application is prior to the installation of drainage tile in locales where sand may occur at the depth of tile. Commonly this soil profile occurs in the flood plain of rivers and under old lake beds. An area in which this occurs is the Red River Valley of Minnesota and North Dakota including the former bed of Lake Agassiz.

Subsoil EC soil Mapping allows tile designers to look into the soil profile without setting a foot in the field. Soil borings may be taken in advance in these “pockets” to determine the percentage of sand, silt, and clay in the soil. With this information, the tile designer can change the tile spacing or the type of tile to be installed depending on the soil profile. Better tile design produces better drainage. Below are some examples of the soil profile at a 3 meter depth, and soil borings with their respective sand, silt, and clay.

Although the above shallow and deep surface maps look similar, they are very different. A drainage system based and designed on the shallow surface information would not be a good match for the deep soil profile.

This example shows the deep surface break lines and the corresponding soil boring locations and values.