Gênese e comportamento físico- hídrico de solos construídos em mina de bauxita no sudoeste paraense.

Abstract

In an area under the influence of bauxite mining, from the company Mineração Paragominas SA, of the Hydro group, on the Miltonia Plateau 3, a study was carried out to evaluate the effect of time and the influence of recovery methods on pedogenesis and physical-water behavior of soils built after bauxite mining. Five areas under recovery were studied: Natural Regeneration, Planting seedlings of different ages, Nucleation and a forest area that served as a reference for the soil in its natural state. For this, the morphological, micromorphological, mineralogical, chemical and physical - water attributes of the soil were evaluated. In constructed soils, part of the morphological characteristics related to color and structure is inherited from the original soil, but structural changes related to compaction, accommodation of matter and clogging of pores are common. There was no great evolution in the pedogenetic processes, except for the formation of new structural units that were observed only in the superficial layers in the older areas, in addition to Fe mobilization features, in compacted layers. Among the five systems studied in different years, the Natural Regeneration system was shown to have a greater potential for the recovery of altered soils and presented a greater pedogenetic evolution in the first centimeters, showing improvements in these attributes mainly in the superficial layer. The RN09_9 system obtained the best responses for soil attributes: CTC, VIB and DMG variables and 2 mm class aggregates, in addition to MOS, demonstrating to be the most promising system in the recovery of soil quality until this study phase. The recovery of most soil attributes at depths less influenced by vegetation cover will take more time.