What is truncated soil and how it is prepared?

Truncated soil is soil that has lost all or part of the upper soil horizon or horizons through erosion or excavation. This means that the topsoil that is necessary for plant growth is gone from soil that is truncated. To prepare it for plant growth, topsoil would have to be hauled in or the truncated soil would have to be "built up" by adding organic matter in order to establish another layer of topsoil.