Grusighet

Grusighet is a term used in soil science and geology to describe the degree to which a soil or sediment contains gravel-sized particles. The word derives from grus, Swedish for gravel, with the suffix -ighet forming a noun that denotes a characteristic or quality.

Definition and measurement: Grusighet expresses the presence of gravel-sized material in a sample. In many soil classification schemes it is quantified as the percentage by volume or mass of particles larger than about 2 millimeters. Soils with higher grusighet have a coarser texture and more coarse voids, which influences their physical properties.

Implications for soil properties: Increased grusighet generally leads to higher drainage and aeration and faster warming in the upper layers, but lower water-holding capacity and reduced surface cohesion. This affects cultivation, fertility retention, and erosion risk. Grusige soils often require management practices to improve nutrient retention and prevent compaction or erosion, depending on land use.

Geological occurrence: Grusighet is common in glacial and fluvial deposits, including tills, moraines, and river gravels. It is frequently used as a descriptor in soil surveys in regions shaped by glaciation, including parts of northern Europe.

Applications and considerations: The degree of grusighet influences agricultural suitability, irrigation needs, and construction considerations such as bearing capacity and frost susceptibility. In planning and land management, recognizing grusighet helps anticipate drainage behavior, erosion risk, and the need for soil amendments.

See also: soil texture, gravel, coarse fragments, drainage, frost heave.