This International Standard specifies a method for the determination of the cation exchange capacity (CEC) at the pH of the soil and for the determination of the content of exchangeable sodium, potassium, calcium and magnesium in soil. Is applicable to all types of air-dried soil samples; pretreatment according to ISO 11464 is recommended. NOTES: 1 The method described suffer from interference from calcium as calcite or gypsum in samples. Also, the presence of any souble salts gives values for the exchangeble cations that are higher than the actual exchangeable amounts[3], [4].2Measurement of the specific electrical conductivity of the soil sample according