Hidrofobicidade em solos arenosos e argilosos sob diferentes usos na região semiárida de Pernambuco

Abstract

The hydrophobicity or water repellency of the soil is a well recognized phenomenon that influences the hydrological behavior of the soil. Water repellent soils resist wetting and inhibit infiltration. Reduction of soil infiltration results in seed germination, plant growth and development, increased runoff, soil erosion, nutrient leaching, especially in regions with heavy rains after prolonged periods of drought. Although water repellency has often been associated with diverse vegetation and coarse-textured soils, several studies have shown that severe water repellency also occurs in several soil types, including those that are well-textured, well-aggregated soils. In this sense, the objective of this work was to identify and characterize the hydrophobicity in sandy and clayey soils under different management conditions (pasture and native vegetation) of Agreste Meridional of Pernambuco, as well as its relationship with some physical, water and chemical properties of the soil. The delimited area was 20x20 m, subdivided into 2x2 m plots. The deformed and undisturbed samples were collected in the 0-10 and 10-20 cm depth layers in an area of natural vegetation, the chemical, physical and water attributes were evaluated, as well as a simple ring infiltration test. For the microbiological analyzes, deformed samples were collected every 2.5 / 2.5 cm depth up to 20 cm, in an area of natural vegetation, which were kept under refrigeration. The degree of repellency performed by the water drop penetration time (TPGA) was more severe in Yellow Latosol than in Regolitic Neosol. Water depth infiltration curves show distinct behavior. In the 0-10cm depth, there was no exponential tendency of the infiltration curve, with constant flow. The pH H2O, soil potential acidity (H + Al) and total organic carbon were significant in the management. The hydrophobicity index (IH) found by the ratio of aliphatic carbon bands and aromatic carbons in the two soil samples was higher in the native forest area than in the caatinga area.