topsoil

This means topsoil contains few of the ingredients needed for long-term successful farming.

Because of this increased concentration, regrowth of plants is minimal, leading to increased erosion, which leads to a decrease in the fertile topsoil, leading to even less regrowth.

As it crashed down the steep mountainside like a gigantic snowplough, it swept up trees, boulders and tons of topsoil, and completely crushed and destroyed the six villages that lay in its path.