Morphological and mineralogical characterization of soils in the Cordillera and Flooding Field environments at the Pantanal Mato-Grossense - Poconé

Abstract

The current study was carried out in the sub-region of Poconé, a wetland area located in Mato Grosso State. The Gleyic Luvisol (LVg) and Dystric Gleysol (GLd) soils were considered for the study as significant representatives of two distinct environments existent in the Pantanal Mato-grossense, the cordillera and periodical flooding field, respectively. The objective was to understand the genesis of the soils from the characterization and study of their morphological and mineralogical properties. The results showed that the difference in moisture between the soils is related to the low difference of elevation from these environments, which affects the soils’ properties. In the Cordillera environment, the soil presents higher contents of free iron, whereas in the periodical flooding field, the soil presents higher contents of amorphous iron or low crystallinity. The extractions pointed out the presence of aluminum under polymeric form or low crystallinity. Among the morphological characteristics, the highest effect of the hydromorphism occurred in the soil of the periodical flooding field. The mineralogy of the clay fraction in both soils showed to be quite similar by constituting a variability of minerals, with emphasis to kaolinite (Ct) and minerals 2:1 such as illite (Il), hydroxy layered vermiculite (VHE) and, possibly smectite (Es) in the soil of the Cordillera environment. It was also confirmed the presence of quartz (Qz). The iron oxides considered predominant in both soils were the hematite (Hm), goethite (Gt) and lepidocrocyte (Lp).