The potential of chemical and spectroscopy characterization in the analysis and classification of horizons from tropical soil

Abstract

This study assessed the chemical and spectroscopic characteristics to contrast the Brazilian Soil Classification System for Latossolo Bruno. The soil samples of A, AB, BA and B horizons from Latossolo Bruno analyzed in this study were collected in Abelardo Luz, Santa Catarina state, Brazil. The humic acid fraction was obtained by chemical fractionation. The soil and humic acid samples were characterized by Fourier transform infrared spectroscopy, ultraviolet visible absorption spectroscopy and scanning electron microscopy. The carbon content was determined by dry combustion. The organic matter spectroscopic characteristics of the A, AB, BA and B horizons from Latossolo Bruno indicate that the changes are not as clear as those observed by parameters used in the Brazilian Soil Classification System. Thus, these results suggest that the qualitative analysis, aromaticity degree and humification index cannot contribute to the pedological classification of soils. The gradual variation in carbon content with soil depth occurred as expected, since the residues are incorporated into the soil in this manner. Altogether, the results reveal that despite the fact that the parameters analyzed did not contribute to soil classification, the study of these parameters provide important information about the soil organic matter.