Editing Vernal pool (section)

==Soils==
Vernal pools can form anywhere that a depression fills with rainwater, leading to low nutrients and low levels of dissolved salts. They are underlain with an impermeable layer of claypan, hardpan, or volcanic rock allowing for water retention. In many instances they contain grasslands that form over a variety of soil types containing silts and clays often covered by a layer of interwoven fibrous roots and dead leaves. The soil types present tend to relate to the local soil types and hydrology of the pool. Finer soils such as clay, silt, and muck are more common in perched situations, whereas pools which are more connected to the water table have more coarse soils like sand or gravel. Soils in vernal pools often reflect their inundated conditions, leading to low chroma horizons, mottling, and anoxic decay. They can develop hydric soils which are typical of flooded areas, including accumulations of organic matter, but this may not happen in drier areas. In some cases there is a hard pan layer which causes the retention of water in the pools.<ref>{{Cite web|url=http://www.eoearth.org/article/Abiotic_factor?topic=49461|title=Abiotic factor|last=Hogan|first=C. Michael|date=July 31, 2010|editor-last=Monosson|editor-first=Emily|website=[[Encyclopedia of Earth]]|publisher=[[National Council for Science and the Environment]]|archive-url=https://web.archive.org/web/20130608071757/http://www.eoearth.org/article/Abiotic_factor?topic=49461|archive-date=June 8, 2013}}</ref> The hardpan clay basin accumulates water due to the small particle size and therefore reduced porosity. This permits flooding and development of vernal pools.{{Cn|date=May 2021}}