Origin and rupture of a podzolized pedological system in the dissected coastal tablelands of the North coast of the state of Bahia

Abstract

The North Coast of the State of Bahia is known for having a diversity of ecosystems and landscapes. However, these ecosystems, located on dunes, marine terraces and coastal tablelands, are very fragile and targeted by tourist developments in the region, making them even more vulnerable to environmental degradation. This fragility comes mainly from the sandy geomorphological surfaces and features, covered by pioneer plant formations. Research in the Coastal Tablelands has shown that the origin of sandy soils with low fertility and high erodibility, especially the Spodosols, is the result of a podzolization process of the lateritic soils in the Coastal Tablelands. However, there are areas where podzolization may have occurred in allochthonous and previously sandy surface formations, such as eolian and fluvial deposits. In addition, the dissection of the Coastal Tablelands has eroded the podzolized surfaces and exposed the Barreiras Formation facies that form soils as fragile as the Spodosols - the Inceptisols. Thus, the aim of this research was to characterize and identify the origin of a Quartzipsamment - Spodosol pedological transformation system, interrupted by a low-slope Inceptisols, in an area of Dissected Coastal Tablelands on the North Coast of Bahia. The construction of a toposequence, combined with geophysical studies and the collection of morphological, chemical and physical soil data, as well as fourier transform infrared (FTIR) analysis of the samples collected, produced data that supported discussions and interpretations on the pedogeomorphological evolution of the slope studied. Thus, the results indicated that the podzolization process occurred in allochthonous sandy deposits, given the high vertical lithological discontinuity presented in the profiles of the upper slope sector of the toposequence. On the other hand, the Quartzipsamment and Spodosol of this sector showed lateral links and a break with the low slope sector which, from the incision of the Coastal Tablelands, formed the Inceptisol on the lower slope over underlying facies of the Barreiras Formation.