Volume 2.10 Electrical conductivity and total soluble salt content
The level of soluble salts found in the soil solution can be classified by determining the electrical conductivity (EC) of the solution, or the soil solution can be assayed for its elemental content. When the level of soluble salts increases, the usual effect is a decrease in plant growth; therefore, the determination of soluble salt is of considerable significance. Soils affected by high levels of soluble salt are also difficult to manage, particularly when sodium (Na+) is the main cation contributing to the high salt level. Salinity, the result of high Na-salt presence, affects about 25 percent of the world’s croplands and is becoming a growing problem in most irrigated croplands. In general, salts can produce both cationic and anionic toxic effects and cause deficiency or toxicity of minor elements that become insolubilized or dissolved with increasing pH. Increasing the percentage of salt also increases the osmotic potential of the soil and thus generates competition for water between the soil and the plant roots.
The methods to quantify SOC already harmonized by GLOSOLAN are the following:
