Topsoil is the upper layer of soil found on the Earth's surface. It is rich in nutrients and organic matter, which are essential for plants to grow and thrive. Full definition
Coast Range site that — per the Forest Service hydrologist — lost a foot of topsoil in the past century and how has about 2/3 of an inch remaining. (realclimate.org)
In May 1934 two dust storms removed massive amounts of topsoil from Great Plains farms and carried it all the way to Chicago, dumping 12 million pounds of dust on that city, before turning toward Boston, New York City, and Washington, DC. (scientificamerican.com)
In 1990, Dr. Peter Borchelt, an applied animal behaviorist, ran three 10 - day tests to determine feline litter preference using a comparison of 14 types of commercial litter as well as topsoil mixed with clay litter and playbox sand. (pets.webmd.com)