Most Manure Nutrients are actually salts.  A salt by its definition is a neutral balance between an acid and base elements or ions.  For example when a Sodium ion and Chloride ion combine it creates a neutral salt.  The salty taste we think of is table salt which is usually Sodium Chloride.

It is the Sodium ion that creates the problem for the soil and the plant cells as that is what prevents the plant from absorboing water or allowing water to flow within its cell structure.

Salts and Sodic soils are more of a problem in arid and semi-arid parts of the country.  This is due to the lack of rain that will flush or leach the salts below the root zone of the crops.

When soil has too much Sodium in it we refer to it as Sodic soil.  It is this Sodium element or ion that is problematic for farmers.  Sodic soil will reduce your crop yield.  Each crop has certain Sodium tolerances that will reduce your crop yields by 10% or more.  Read the articles below to understand salts better.

Sodic soils is rarely caused by application of manure slurries, as those application rates are generally under one acre inch of water.  The problem is generally from irrigating your fields with lagoon water which has a high level of  Sodium ions in the solution.  When irrigating with lagoon water you are often putting on 10 or more acre inches per year.  The key to irrigating with lagoon water is to mix it with equal amounts of well water as it is being irrigated.

The usual solution for Sodic soil is to apply Gypsum or Lime as well as flushing the soil with rain or well water with low Sodium content.  

Provided below are internet articles that we feel our friends in farming will find useful in planning their manure and irrigation use.