GEOG 3600 Lecture Notes - Cation-Exchange Capacity, Clay Minerals, Soil Horizon
Document Summary
By knowing the cec of the clay-size fraction in soil, it is possible to find out clay minerals present. In this report, the cec per 100 g clay has been compared with the % c/100 g clay in order to find out what clay minerals might be present in the soil. The cec of a soil, or its cation exchange capacity, is the maximum ability of a soil to hold cations available for exchange, and is expressed as milliequivalents/100 g soil. Various clay- size minerals have cecs that fall within certain limits, and by knowing the cec of the clay- sized fraction in the soil it is possible to estimate the clay minerals present. Cec varies with clay mineral species, in addition to organic matter content, and the higher the organic matter content of the soil, the higher cec will be (birkeland, 1999).