Hienopesuinen

Hienopesuinen is a Finnish term used in pedology and geomorphology to refer to a soil or sediment with a predominantly fine-grained texture, rich in silt and clay. The word combines hieno, meaning fine, with pesuinen, related to washing, reflecting the material’s fineness and the way fine particles are transported and deposited by water. The term is specialized and its exact definition can vary between Finnish classification systems and literature.

Characteristics of hienopesuinen soils typically include a high content of clay and silt, low sand content, high plasticity and cohesion when wet, and a high water-holding capacity with generally low permeability. They tend to form under low-energy depositional conditions, such as quiet floodplains, lake shores, deltaic environments, or glaciolacustrine settings, where suspended sediments settle out and fines are retained. In weathering contexts, they may also develop from the alteration of primary clays and silts.

Management and use considerations include potential problems with aeration and drainage, as these materials compact easily and can exhibit shrink-swell behavior. Agricultural use often requires drainage improvements, soil structure amendments, additions of organic matter, and careful water management. In construction, hienopesuinen materials can pose challenges for foundations and earthworks due to variable settlement and low bearing capacity.

Notes: terminology varies, and some sources may categorize these materials under broader texture classes such as silty clay or clay loam rather than as a distinct class. See also soil texture, clay, silt, loam, drainage.