Hidrofobicidade e sua interação com as propriedades hídricas do solo

Abstract

Hydrophobicity can be defined as the difficulty of wetting the soil by water, due to the coating of the soil particles (sand, silt and clay) by organic hydrophobic substances. Initially, the phenomenon was related to areas subject to fires. However, recent studies have shown that the phenomenon is linked to several other factors, being: soil moisture, which has been directly related to the manifestation of soil hydrophobic character; vegetation, which can be a source of hydrophobic organic compounds; microorganisms, especially bacteria, which play an important role in the selectivity of the compounds to be decomposed; and the anthropic action itself. Thus, the present research related the interaction between the soil water properties and the hydrophobicity, seeking to understand the influence of the hydrophobic organic compounds under the properties of a Yellow Latosol with humic A. The studied areas were located in the municipality of Brejão, located in Agreste Meridional Pernambucano, under the same topographic and climatic conditions, differing only in the form of land use (native forest and pasture). The areas with 20x20 m were subdivided into 2x2 m plots, and 5 plots were selected in each of the areas. Water and alcohol infiltration tests were performed, the water drop penetration time, the repellency index and the water and alcohol sorption were calculated. The water properties of the soil varied significantly according to the analyzed area and the depth, presenting a reduction of the hydrophobicity with the increase of the depth and with the change of the form of use. The native forest area due to the greater increase of organic matter, mainly in the more superficial layer, presented reduction of the infiltration and the sortivity to the water due to the hydrophobicity performance. Conversely, the pasture area was free of the occurrence of the phenomenon of hydrophobicity.