Useful Articles and Information
CSU Extension Factsheets: (also available from the Extension publications website)
Poor plant growth can sometimes be attributed to high salts in the soil. Salt content can be measured by analyzing the soil for electrical conductivity (EC) and is expressed in units called millimhos/cm (mmhos/cm).
Salts can be naturally occurring in low lying areas where the water table may be close to the surface or they can become high through the addition of too much manure or other high salt containing compost.
Adding composts or composted manures at a rate of 3 cubic yards per 1000 square feet (about one inch thick on the surface of the soil) and then tilling or rototilling them in about six inches is usually sufficient to prevent high salt concentrations in the soil. Care should also be used when purchasing topsoil to avoid soil that is high in salts.
Some topsoils are mixed with composts or manures which can improve soil structure and nutrient levels, but can also result in high salt concentrations that are detrimental to plants. With some topsoils being delivered at rates of $25 to $40 per cubic yard, it pays to find out if the soil will be acceptable for plant growth by knowing the salt level or EC.