Caracterização de solos coesos com diferentes cores em tabuleiro costeiro do litoral norte da Bahia

Abstract

Barreiras Formation is known as neogenic sediment from predominantly continental and seaside origins, sandy and clay and variegated colors, which are distributed along the Brazilian coast from the Amapá to Rio de Janeiro. Soils formed from this material usually present horizon with strong cohesion between the particles which is associated with multiple factors and interrelated, mainly mineralogical, chemical and physical. Although the Brazilian System of Soil Classification assigns the term "cohesive" only to the class of Yellow latosoils and Yellow Argisoil and Greyish Argisoils, in the third categorical level, there is record of this occurrence in Red-yellow and Red Latosoils and Argisoils in the region of Coastal Tablelands. So far, the research has shown that cohesion can be caused by the adjustment of soil particles, promoted by wetting drying cycles and that the presence of organic matter, iron oxide and aluminum and sand, can reduce effect of the soil cohesion. This study analyzes cohesive soils, with different colors in Coastal Plain of the North Coast of Bahia, highlighting its genesis, morphology and classification. In addition, it will evaluate the resistance to penetration of these soils; field measurements will be carried out before and after soil management by subsoiling in areas planted with eucalyptus, and also in the laboratory after application of wetting drying cycles. To carry out the work, cohesive red, red-yellow, yellow and gray soils were collected from sedimentary geological material forming Barreiras in the municipality of Inhambupe-Ba. The soils were described in the field and samples were collected for morphological, chemical, physical and mineralogical and retrofitting of the experiments under controlled conditions. The soils showed moderate to strong cohesion, regardless of color, possibly associated with kaolinite matrix, clay migration between the horizons and wetting drying cycles.