Lessivage, or argilluviation, refers to the movement of fine clay minerals from the upper part of a soil to the lower part of a soil, via the downward movement of water through the soil matrix. Lessivage is the primary mechanism in the formation of the diagnostic, clay-enriched argic, or Bt horizon (Canadian System of Soil Classification) of Luvisolic soils.
Lessivage, or argilluviation, refers to the movement of fine clay minerals from the upper part of a soil to the lower part of a soil, via the downward movement of water through the soil matrix. Lessivage is the primary mechanism in the formation of the diagnostic, clay-enriched argic, or Bt horizon (Canadian System of Soil Classification) of Luvisolic soils.
== Mechanisms == Lessivage occurs when water that infiltrates the soil picks up negatively charged clay particles, creating a colloid suspension, and carries them downward until changes in the soil physical or chemical environment cause the clay to settle out by flocculation. Clay particles settle out of the water if the water remains stagnant for a long period of time, or the clay interacts with positively charged ions deeper in the soil. These interactions create larger molecules that settle out more quickly than clay alone. As the clay and clay complexes accumulate lower in the soil, soil pore-sizes become finer at the zone of accumulation, referred to as the illuvial horizon, further promoting the deposition of clay.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).