Principal components analysis of the chemical attributes of the soil of a preserved Cerrado fragment

Abstract

The number of studies on the importance of Cerrado soil to biogeochemical cycles is growing, with this being the focus of most research in the Cerrado biome. The objective of this research was to verify the correlation among different chemical attributes of the soil in a Cerrado fragment located in Mãe Bonifácia Park, in Cuiabá, Mato Grosso (MT), Brazil, using principal components analysis. For this study, five soil samples were collected at 0-10 cm depth monthly from August 2015 to July 2016. After the collection and identification of the soil, chemical analyses were performed to determine the following chemical characteristics of the soil: organic matter (OM), base saturation (V%), sum of bases (SB), cation exchange capacity (CTC), pH, and concentrations of H+, Al3+, Ca2+, Mg2+, K+, P, S, Cu, Mn2+, Mg2+, Zn, Fe2+ and B3+. The soil was characterized as acidic, which is typical for Cerrado soils, although some chemical elements were found in high concentrations. After the analysis of principal components, it was possible to reduce the seventeen original variables to four principal components that represented 88.86% of the total variation of the data. In which the first main component explained 41.18%, the second component explained 28.39%, the third 11.29% and the fourth explained 7.98%. Based on this analysis, it was identified that the chemical attributes such as the sum of base (SB), organic matter (OM), cation exchange capacity (CTC), calcium (Ca2+), saturation (V%) and pH represented the greater data variance.