Evaluation of Cation Exchange Capacity (CEC) in Tropical Soils Using Four Different Analytical Methods

Abstract

The research was partially sponsored by FAPESP nº 93/1480-0 and CNPq/Finep nº 505085/2004-6. Abstract Four analytical methods for determination of cation exchange capacity (CEC) in tropical soils were tested, aiming to define what the most appropriate based on the requirements: analysis time, degree of reliability and cost of operation. A total of 444 soil samples from the Amazon rainforest and Atlantic rainforest were analyzed in eleven soils types. Organic matter, pH and ions Na + , K + , Ca 2+ , Mg 2+ and H + +Al 3+ were also analyzed. The influence of the action of fire on the release of ions to the soil was also tested. The results indicated that there was a momentary increase in CEC in the soil after a fire. Tropical soils have a high humidity and acidity, contributing to an overall increase of CEC. Adverse climatic conditions in the tropics affect soil properties, so that practical methods and low cost have the advantage that they can be applied periodically to analyze the quality of the soil.