Characterization, classification and use interpretations of a sequence of soils along the Transamazon highway, of Brazil, between the Xingu and Jacaré rivers / Antonio M. Pires-Filho.

Tese (M.S.)- Michigan State University, 1978

A sequence of four profiles (numbered from highest to lowest) was studied. The soils were relatively shallow, and physical tests show that the two better drained profiles have plinthite in their subsoil horizons. Chemical analyses show profiles 2 and 3 have high A1+++ saturation. All soils studied have low exchange capacity and percent base saturation. Kaolinite comprised more than 95 percent of the total clay fraction. Aluminum saturation seems to have more influence on x-ray diffraction intensity than soluble iron oxides in the samples. Pretreatments of clay by dithionite and oxalate increased the kaolinite diffraction peaks in all subsurface samples; but, dithionite was most effective. Oxalate treatments were not effective on surface samples. Taxonomically, these soils fit into Plinthic Paleudults (Profile 1), Plinthudults (Profile 2), and Aquic Paleudults (Profiles 3 and 4). The two more poorly drained soils (Profiles 3 and 4)had severe limitation for all purposes, but the two better drained (Profiles 1 and 2) had less limitations for some purposes.