Alterações do fluxo hídrico e seus efeitos na dinâmica do ferro e na estrutura de um Latossolo Amarelo na Amazônia

Abstract

The substitution of primary forest for agricultural activities in the xanthic ferralsols, medium texture. The predominant soil class in the northeast of the State of Para – Brazil, may cause changes in the soil structure and water flows. The hypothesis was that due to deforestation and its subsequent agricultural use occur reduction in evapotranspiration rates, and reduction the infiltration and transmission of water into the soil. As a result, soil becomes more humid and close to saturation, and remains in this situation for long periods, reduced oxi-redox potential leading to changes in soil characteristics in special in the iron minerals responsible for the cementation and aggregation of these xanthic ferralsols. The study focused on the physical-chemical and mineralogical characterization of a xanthic ferralsol, in the city of Mojú – PA. In filed, total iron, pH and electrical conductivity in the soil solutionwas monitored. In the laboratory was carried out experiments to verify the effect of flooding in the aggregate stability. It was adjusted soil physical parameters to modeling of soil water potential dynamics in three systems of use of the land: area without vegetation, oil palm plantation (Elaeis guineensis Jacq.) and primary forest. The results evidenced that xanthic ferralsols, under oil palm plantation or without vegetation cover remained for long periods near saturation. The reduction of the iron that migrates to the soil solution was also detectedas consequence of flooding, and it provokes a destabilization of the soil structure.