Abstract. Amazonian soils are heterogeneous. However, few studies have been
carried out in the Amazon, mainly because of its considerable size, which
complicates the collection of data and the ability to plan for the
sustainable use of natural resources. In this study, the physical, chemical,
and mineralogical attributes of soils in the state of Pará, Brazil, were
characterized by examining the particle size, fertility, silicon extracted by
sodium hydroxide, iron, and aluminum, and manganese extracted by sulfuric acid,
sodium citrate-bicarbonate-dithionite, and ammonium oxalate + oxalic
acid. A descriptive analysis, multivariate principal component analysis, and
cluster analysis were performed. The soils had low concentrations of
bioavailable P, Ca2+, Mg2+, and K and had high
concentrations of Al3+, Si, and Al oxide in the Cambisols.
Concentrations of Fe and Mn oxides were higher in both the Cambisols and
Nitosols, which are rich in oxidic minerals. The multivariate analysis
indicated an association between the organic carbon content and pH, P, Ca,
Mg, and K concentrations. An additional association was observed between
clay, potential acidity, and the Fe and Al oxide concentrations.
