Argillipedoturbation, sometimes referred to as self-mulching, is a process of soil mixing caused by the shrinking and swelling of the

smectite A smectite (; ; ) is a mineral mixture of various swelling sheet silicates (phyllosilicates), which have a three-layer 2:1 (TOT) structure and belong to the clay minerals. Smectites mainly consist of montmorillonite, but can often contain secon ...

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...

s contained in soil. It is an effect specific to soils of the

vertisol A vertisol is a Soil Order in the USDA soil taxonomy and a Reference Soil Group in the World Reference Base for Soil Resources (WRB). It is also defined in many other soil classification systems. In the Australian Soil Classification it is c ...

ic variety, and is triggered by the constant cycles of wetting and drying. It is characterized by wide (up to ), deep ( or more) vertical cracks in the

solum The solum (plural, sola) in soil science consists of the surface and subsoil layers that have undergone the same soil forming conditions. The base of the solum is the relatively unweathered parent material. Solum and soils are not synonymous. So ...

that contain differing materials from the rest of the soil layer they are found in, as well as sloughed-in surface materials. In order for argillipedoturbation to occur, the soil must be at least 30% clay content. The expression of argillipedoturbation depends to a large degree on the exact clay content of the soil, as well as on what other minerals make up the soil composition. Argillipedoturbation can be strong enough that it can affect the

soil horizon A soil horizon is a layer parallel to the soil surface whose physical, chemical and biological characteristics differ from the layers above and beneath. Horizons are defined in many cases by obvious physical features, mainly colour and texture. ...

s by combining the different horizons, making them difficult to distinguish. It can also result in a gently-rolling surface referred to as

gilgai A gilgai is a small, ephemeral lake formed from a surface depression in expanding clay soils. Gilgai is also used to refer to the overall micro-relief in such areas, consisting of mounds and depressions. The name comes from an Australian Aborigin ...

topography and in the dramatic soil inclusions known as slickensides. In addition, argillipedoturbation sometimes results in a chernozemic-like A-type horizon, or one resembling a gleysolic order soil. This process can also affect the distribution of rock fragments, by moving fragments at the surface to lower soil layers and vice versa. The effects of this process are useful in agriculture, as the organic surface materials fertilize the soil and cause them to become very productive when irrigated. However, they are very difficult to plow and manage due to the high, thoroughly mixed clay content.

References

{{reflist, 2 Soil mechanics