Caracterização física, química e mineralógica de alguns solos do Campus da Universidade Federal do Amazonas - Manaus (Am)

Abstract

Morphological, physical, chemical, and mineralogical organizations were conducted on soils desrived from the Alter do Chão Formation sediments, which occupy the Universidade Federal do Amazonas (UFAM) campus, for the aim of subsidizing the understanding these soils’formation processes and classification. Five soil profiles were selecred in two toposequences: profile (CAM1), occurring on the relief’s high part (top); on backslope (CAM2 and CAM4) and on foot slope (CAM3 and CAM5). Profile CAM6 is located on a different area from the others, namely the sandy region. The soils were described morphologically and submited to granulometric, chemical, and mineralogical analyses. The profiles presented A-B and A-C horizon sequences. CAM1 with granular structure and very small blocks; and CAM2 with medium-sized blocks structure, reveal water dynamics influence in the transformation from Bw to Bt. Profile CAM1 (top) presents a very clayey texture, just as CAM2 e CAM4 profiles related with a colluvium mantle, present médium- clayey texture. Profile CAM3, from mixed colluvium and alluvium sediments, dysplay glerization colors and medium/sandy texture, similar to that of CAM5 profile. CAM6 profile testure is typical to the sandy domain. Soils were moderately to highly acidic, allic and dystrofic, with ki ratio around 2.0, indicating a high extent of weathering. The mineralogical examination recorded kaolinite with a high crystallinity degree in every soil. Profiles were classified as Yellow Latosol (CAM1), Yellow Argisol (CAM2 and CAM4), Fluvic Neosol (CAM3), Cambisol (CAM5), and Quarzipsammentic Neosol (CAM6).