Chemical, physical and mineralogical attributes of the soils of the Sertanejo pediplain in the sisal-growing areas of the semiarid Bahia

Abstract

Information and available knowledge of the soils of the Sertanejo pediplain are relatively scarce and restricted to survey data. Researches about soil characterization and classification contributes to the knowledge of different soil orders within a region and allows information to be obtained systemically based on the physical, chemical, and mineralogical properties of the soil. This study aimed to evaluate the genesis of the Sertanejo pediplain soils, through the characterization of the chemical and mineralogical properties and classification of the soils of the sisal-growing region. Five soil profiles located in Araci, Retirolândia, St. Dominic, and Valente, cities located in the sisal-growing areas of the Bahia semiarid region, were studied, described morphologically, and analyzed for chemical (pH H2O and KCl, Ca2+, Mg2+, K+, Na+, Al3+, H+ + Al3+, P, and TOC) and mineralogical attributes. Most evaluated soil classes were formed by lithological discontinuity of material. The main processes involved in the formation of such soil classes were: cumulization, accretion, and lessivage. The mineralogy of the clay fraction observed was complex and included a variety of minerals, with a predominance of kaolinite and bayerite. In addition, we also found goethite and illite in most of the studied profiles, both in the sediment, horizons P1 C2, and in the crystalline horizon P1 Cr, P2 Bi, P3 2Cr, and P5 Bi. The soils were classified up to the fourth category level, as Entisol Eutrophic Inceptisol (RRE), Alfisols Haplic typical Eutrophic (SXE), and Inceptisols Ta Eutrophic vertissólico (CXve).

Lateral loss of clay in the genesis of Luvisols in the Semi-Arid Depression of the Jequitinhonha Valley, Minas Gerais - Brazil

“…The observed silt contents were relatively low (Table 1). Similar results were found by Sacramento et al (2019) in soil with Bt horizon and c high activity clays in semi-arid region of Bahia, where probably the striking contraction of this type of clays during the day period contribute to the breakdown of silt particles. Unlike other Luvisols from northeastern Brazil (Oliveira et al, 2009;Fernandes et al, 2010), Nigeria (Ajiboye et al, 2019) and Italy (Costantini et al, 2018), none of the Luvisols in this study have gravel.…”

“…The values obtained for soil organic carbon are higher than those found by some authors (Luz;Mermut, 1992;Corrêa et al, 2003) in Luvisols of the Northeast region of Brazil, and also higher than those found by Sacramento et al (2019) in other soil classes of semi-arid in Brazil. However, Luvisol profiles studied in Brasil (1987) in the semi-arid region of Minas Gerais registered values of organic carbon similar to those found in this study, very likely due to the less severe climate conditions (seasonal deciduous forest) than in the semi-arid region of the Northeast, dominated by the xeric shrubland ecoregion.…”