Newswise — February 17, 2020 – Alluvial soils are soils deposited by surface water. You’ll find them along rivers, in floodplains and deltas, stream terraces, and areas called alluvial fans. The Soil Science Society of America’s (SSSA) February 15th Soils Matter blog explores the definition and importance of alluvial soils.

According to blogger Matthew Ricker, “This is an important category of soils. They provide many functions in our ecosystem. Alluvial soils remove sediments and nutrients flowing in the adjacent water. They can also remove other contaminants from rivers and improve water quality for downstream communities!”

All alluvial soils form by flooding. Because floods periodically deposit new sediment at the surface, alluvial soils can have a unique layered look. Dark and light colors alternate, along with assorted sizes of gravel particles. This unique layering process is called stratification.

In many places around the world there are distinctly different soil colors, chemical properties, and human artifacts buried in floodplains. These allow scientists to reconstruct human occupation and land use history.

To learn more about alluvial soils and their benefits to society, read the entire blog post:  

Follow SSSA on Facebook at, Twitter at SSSA_Soils. SSSA has soils information on, for teachers at, and for students through 12th grade,

The Soil Science Society of America (SSSA) is a progressive international scientific society that fosters the transfer of knowledge and practices to sustain global soils. Based in Madison, WI, and founded in 1936, SSSA is the professional home for 6,000+ members and 1,000+ certified professionals dedicated to advancing the field of soil science. The Society provides information about soils in relation to crop production, environmental quality, ecosystem sustainability, bioremediation, waste management, recycling, and wise land use.

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