Caracterização de diferentes solos por meio da espectroscopia de infravermelho com transformada de Fourier

Abstract

The soil is the largest constituent of occupation of the planet consisting of solid part, liquid and gas. As its composition can infer that has inorganic and organic materials. The objective of this study was to characterize by Fourier transform infrared spectroscopy (FTIR) different soils: Argissolo, Cambissolo, Gleissolo, Latossolo e Planossolo. The five soils were collected at 0 to 20 cm layer. After sampling, the samples were dried at 40 ⁰C and gently crushed to pass through a 2 mm sieve. The soil organic matter chemical fractioning to obtain the humic acid fraction was carried out following the methodology suggested by the International Humic Substances Society (IHSS). FTIR measurements were performed on a frontier spectrophotometer (Perkin Elmer, USA) equipped with a KBr beam splitter and DTGS detector. Spectra were collected in the KBr transmission mode (1.5 mg sample: 150 mg KBr) over a range of 4000–400 cm−1 by co-adding 64 scans at a resolution of 4 cm−1.. The results were statistically analyzed by chemometric tools, principal component analysis (PCA) and hierarchical cluster analysis (HCA). Finally the results obtained through the qualitative analysis of the spectra showed: (1) that in general the soil and AH are similar; (2) HA showed greater intensity at 1630cm-1 to HA that the soil. Quantitative analysis of soil does not show separation between them, this behavior can be due to heterogeneity of samples and to small amount of mass used for the HA characterization. Was observed the grouping of samples in three groups, It is composed of the Argissolo, another by Planossolo and another containing soils, Cambissolo, Gleissolo and Latossolo.