Caracterização física e química de dois perfis de solo, no município de Santo Antônio do Içá, Alto Solimões, Amazonas

Abstract

Pedology in the Amazon does not focus much effort on the Upper Solimões region, concentrating instead on the Middle Solimões, leaving a gap in most of the Upper Solimões region. This allows for the disorderly use and management of natural resources (soil), which is almost commonplace. The distance from large centers and the lack of professionals in the field seem to be responsible for this. To begin filling this gap in pedological information, we propose to study the genesis and physical-chemical attributes of two Spodosols in the municipality of Santo António do Içá, in the Upper Solimões region of the state of Amazonas. Two trenches were dug in low, flat areas, and the horizons/layers were identified and collected in samples of approximately 500 grams, which were conditioned in fine dry air (TFSA). The following are being evaluated: granulometry, aiming at the separation and quantification of sand, silt, and clay fractions, as well as: active acidity (pH), exchangeable calcium (Ca2+), exchangeable magnesium (Mg2+), exchangeable sodium (Na+), exchangeable potassium (K+), available phosphorus (P), exchangeable acidity (Al3+), potential acidity (H+ + Al3+), and total organic carbon (C). Based on the results of the chemical analyses, the sum of bases (SB), cation exchange capacity (CTC), effective cation exchange capacity (t), percentage of saturation by bases (V), and percentage of saturation by aluminum (m) will be calculated. The partial results show that the two trenches are classified as Espodossolos, sandy soils covered by “fragile” Campinaranas vegetation. The B horizons are spodic and have a hardened layer (Ortstain), which seems to be common in these low, flat areas. At the end of this study, a brief pedological diagnosis is expected to indicate a possible use and management of these environments and a minimal contribution to Amazonian pedological science.