Cation exchange capacity

Negative charges on the surfaces of soil particles bind positively-charged atoms or molecules (cations), but allow these to exchange with other positively charged particles in the surrounding soil water. Bufret Lignende Oversett denne siden CEC is an inherent soil characteristic and is difficult to alter significantly. Soils with a higher clay fraction tend to have a higher CEC. Organic matter has a very high CEC.

Sandy soils rely heavily on the high CEC of . Soil nutrients exist as positively charged or negatively charged ions when dissolved. Cation exchange capacity. In other words, it is a measure of the number of negatively charged binding sites in the soil, which can be summed up as the nutrient holding capacity of the soil.

It is determined by the negative electric charge on the surface of soil particles. This charge attracts the cations, restricting them from leaching away. CEC , as reported by nearly all soil testing laboratories, is a calculated value that is an estimate of the soils ability to attract, retain, and exchange cation elements. In order for a plant to absorb nutrients, the nutrients must be . The phenomenon is called . In formation evaluation, it is the contribution of cation-exchange sites to the formation . Soils are composed of a mixture of san silt, clay and organic matter. Both the clay and organic matter particles have a net negative charge.

Thus, these negatively-charged soil particles will . As such, the CEC is a property of a soil that describes its capacity to supply nutrient cations to the soil solution for . Generally speaking, a sandy soil with little organic matter will have a very low CEC while a clay soil with a lot of organic matter (as humus) will have a high CEC. A method of measuring the pH-dependent cation-ex- change capacity of soils is described and data for sur- face soils are presented and discussed. Explained in an interactive way to watch.