Pronunciation: [ɪlˌuːvɪˈe͡ɪʃən] (IPA) 
The spelling of the word "illuviation" may seem tricky, but it can be easily grasped with the help of IPA phonetic transcription. The word is pronounced as /ˌɪluːvɪˈeɪʃən/ in IPA. The initial syllable is pronounced as "ill" followed by "u" as in "up" and "viation" is pronounced as "vee-ay-shun". Illuviation refers to the downward movement of soil particles and minerals due to the action of rainfall or irrigation.
Illuviation is a term used in soil science and geology to describe the process by which material, such as clay, silt, or organic matter, is leached or washed from the upper soil horizons and accumulates in lower horizons or layers. It refers to the transportation and deposition of these materials downwards through the soil profile, usually under the influence of water or gravity.
During illuviation, water movement or percolation carries suspended fine particles, minerals, and organic substances from the upper horizons to the lower horizons of the soil profile. This process causes the accumulation of these materials in lower soil layers, resulting in illuvial horizons or illuvial deposits. Illuvial horizons often exhibit different physical and chemical properties compared to the upper soil horizons, such as increased clay content, darker color, and higher nutrient or mineral concentrations.
This process is commonly observed in soil formations with a distinct profile development, such as in pedogenesis (soil formation) influenced by a variety of factors such as climate conditions, topography, vegetation, and parent material. Illuviation plays a crucial role in the formation and differentiation of soil horizons, affecting various soil properties such as fertility, drainage, and nutrient availability. It is an important process to consider in soil classification, evaluation, and management, as it provides insights into soil formation and the potential characteristics of different soil layers.
The word "illuviation" comes from the Latin term "illuviēs", which means "washing in". "Illuviation" was coined in the early 20th century by soil scientists to describe the process by which material is washed or leached from one soil horizon (layer) to another under specific conditions. It is derived from the Latin prefix "in-" or "il-", meaning "in" or "into", and "lavare", meaning "to wash". This term is often used in the context of soil formation and the movement of minerals and organic matter within the soil profile.
