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Title: LOESS

item Rhoton, Fred

Submitted to: Encyclopedia of Soil Science
Publication Type: Other
Publication Acceptance Date: 6/30/2003
Publication Date: 7/15/2003
Citation: Rhoton, F.E., Markewich, H.W. 2003. LOESS. Encyclopedia of Soil Science. DOI: 10.108/E-ESS 120006646, pp. 1037-1041.

Interpretive Summary: Environmentally and culturally, loess deposits are considered both as assets and detriments. Some of the most fertile, highly productive agricultural soils in the world are developed on loess, which is inherently high in plant nutrients, available water holding capacity, and porosity. Conversely, there are many problems associated with loess due to its unfavorable physiochemical properties. Most unweathered loess is devoid of cementing agents such as clay, iron oxides, and organic matter. This lack of cementing agents results in unbound silt-size particles that do not form erosion-resistant structural units, which in turn results in loess and loess-derived soils having very low resistance to water and/or wind erosion. Loess erosion results in significant local-to-regional degradation of soil, water, and air quality.

Technical Abstract: For almost two centuries the study of loess and loess-like deposits has provided controversy and consternation. In general, loess is considered to be largely unstratified silt-sized dust/material that mantles the landscape in blanket-like deposits. Loess deposits are widely distributed, with the most extensive deposits occurring in the central United States, eastern China, northern Europe, and Argentina. Loess deposits also are recognized in Alaska, Siberia, and Canada.