Cation exchange capacity (CEC) is the ability of soil to hold and exchange positively charged ions (cations) such as calcium, magnesium, potassium, and sodium. CEC is an important measure of soil fertility because it indicates the soil�s capacity to retain nutrients that plants can use. Soils with high CEC, like clay and organic-rich soils, are better at holding nutrients, while sandy soils with low CEC may require more frequent fertilization.
