<P> Topsoil depletion occurs when the nutrient - rich organic topsoil , which takes hundreds to thousands of years to build up under natural conditions , is eroded or depleted of its original organic material . Historically , many past civilizations ' collapses can be attributed to the depletion of the topsoil . Since the beginning of agricultural production in the Great Plains of North America in the 1880s , about one - half of its topsoil has disappeared . </P>
<P> Topsoil depletion occurs when the nutrient - rich organic topsoil , which takes hundreds to thousands of years to build up under natural conditions , is eroded or depleted of its original organic material . Historically , many past civilizations ' collapses can be attributed to the depletion of the topsoil . Since the beginning of agricultural production in the Great Plains of North America in the 1880s , about one - half of its topsoil has disappeared . </P>
which layer of soil is the most fertile
which layer of soil is the most fertile
Topsoil
Topsoil