The cation exchange capacity (CEC) is a value given on a soil analysis report to indicate its capacity to hold cation nutrients. The CEC, however, is not something that is easily adjusted. It is a value that indicates a condition or possibly a restriction that must be considered when working with that particular soil. Unfortunately CEC is not a packaged product. The two main colloidal particles in the soil are clay and humus and neither are practical to apply in large quantities.

The disadvantages of a low CEC obviously include the limited availability of mineral nutrients to the plant and the soil’s inefficient ability to hold applied nutrients. Plants can exhaust a fair amount of energy (that might otherwise have been used for growth, flowering, seed production or root development) scrounging the soil for mineral nutrients. Soluble mineral salts (e.g. Potassium sulfate) applied in large doses to soil with a low CEC cannot be held efficiently because the cation warehouse or reservoir is too small.

Water also has a strong attraction to colloidal particles. All functions that are dependent on soil moisture are also limited in soils with low CEC. Organisms such as plants and microorganisms that depend upon each other’s biological functions for survival are inhibited by the lack of water. Where there is little water in the soil, there is oftentimes an abundance of air which can limit the accumulation of organic matter (by accelerating decomposition) and further perpetuate the low level of soil colloids.