Sensoriamento próximo para caracterização de perfis de solos do Cerrado e Amazônia

Abstract

Tropical soils, especially Brazilian ones, are characterized by being deep. Due to high temperatures and humidity, they are also highly weathered, resulting in low fertility and high concentration of iron and aluminum oxides. The use of proximal sensors, such as portable X-ray fluorescence (pXRF) equipment, which determines the elemental composition of the analyzed material, has aided in this detailed, quantitative, and spatially explicit characterization of soil profiles through digital morphometrics. The first study area is represented by an area under different land uses (Annual Cultivation and Native Forest) with the same soil class, the Oxisols, in the Amazon biome. The second is a Catena, with the landscape located in the Cerrado biome, featuring distinct soil classes (Entisols - Psamments, Inceptisols, Oxisols and Entisols - Fluvents). The objective for the first area was to evaluate and characterize the attributes of four Amazonian Oxisol profiles: two in cultivated areas and two under native vegetation adjacent to the cultivated profiles. The study included textural variations within each land use (one pair of more clayey soil profiles and another pair more sandy). The second study aimed to evaluate and characterize soil profiles with digital morphometrics in a catena in the Cerrado with different soil classes. Digital morphometry revealed explicit variability in textural fractions (clay predominant at depth, sand at the surface) and in the distribution of chemical elements, even in supposedly homogeneous horizons and with distinct soil classes. The sensors and equipment used brought robustnessto the obtained results, aiding in the characterization of these profiles under conditions that have been little explored in previous studies on tropical soils.