Illuviáció

Illuviáció is a geological process that occurs in soil formation, specifically within the B horizon. It describes the accumulation of materials that have been leached from the upper horizons (O, A, and E) of the soil profile. These materials, primarily clay minerals, organic matter, iron and aluminum oxides, and carbonates, are transported downwards by percolating water.

The process begins with eluviation, the removal of these soluble and suspended substances from the overlying layers. As water moves through the soil, it dissolves and carries these particles. When the water reaches a less permeable layer or its movement slows down, the dissolved and suspended materials are deposited, leading to the formation of the illuvial horizon.

The presence and type of illuviated materials are key characteristics used to classify soil horizons. For instance, a Bt horizon indicates the accumulation of clay, while a Bh horizon signifies the accumulation of organic matter. Illuviation is a crucial factor in developing distinct soil profiles and influences soil properties such as texture, structure, color, and fertility. The rate and extent of illuviation are influenced by factors like climate, parent material, topography, and vegetation.