CEC (Cation Exchange Capacity) & PBS (Percent Base Saturation)

CEC (Cation Exchange Capacity) is a parameter characterizing the content of all major exchangeable cations of the soil. Analogue of the Soviet.

Under the main exchange cations mind calcium, magnesium, potassium, sodium and hydrogen. The value for hydrogen is obtained using buffer acidity, for calcium, magnesium, potassium, and sodium, using 1N NH₄OAc.

The value of CEC depends on the content of clay and organic matter.

PBS (Percent Base Saturation) is the percentage of the main exchange cations of the soil, taking the CEC value to be 100%.

A correlation should be observed between CEC values, organic matter and soil texture. With low organic matter and light texture, there should be no high CEC values. Conversely, heavy clay soils should have a high organic matter value and good CEC values.

At high Base Saturation values ​​(%) for some elements, the following conclusions can be drawn:

H> 33% is a big problem, liming is necessary;
Na> 5% – a big problem, you need gypsum;
Mg> 33% – a big problem, you need gypsum.