Comparison of appropriate cation exchange capacity (CEC) extraction methods for soils from several regions of Indonesia

Abstract

Soil-forming factors strongly influence soil diversity in Indonesia. Indonesia is rich in variations of tropical soil types that have distinctive characteristics. Cation exchange capacity (CEC) is an indicator of the soil ability to absorb and supply nutrients so that CEC is used as an index of soil chemical fertility. The factors that affected CEC are the amount of clay texture, organic matter content, and pH. In standard method, CEC is obtained by ammonium acetate 1 N pH 7 method, while the distribution of soil pH in Indonesia is very diverse from pH 4 to pH 8. Also, there are differences in factors that affect CEC, causing the CEC values to be biased or does not reflect the real conditions. The purpose of this study was to obtain the best soil CEC extraction method. 97 soil samples were analyzed with 1 N ammonium acetate extract pH 4.8, pH 6.0, pH 7.0, and compulsive cation exchange extraction method. The result showed that the ammonium acetate pH 7.0 method had a significant correlation to other methods and to pH (H2O). The ammonium acetate pH 7.0 method could be applicated for acidic and alkaline soil.