Hard layer (Hardpan (duripan))

 Hard layer (Hardpan (duripan))

1) The hard layer formed by the cementation of clay, lime, humus and iron compounds transported from the upper part of the soil by accumulating in the lower layer (sometimes below the A and sometimes below the B horizon). The hard layer, which is mostly formed in arid regions, prevents the roots of plants from going deep.

2) A layer of soil that hardens extremely when dry, formed by the cementation of soil particles(s) with organic matter and iron or with silica, sesquioxides, calcium carbonate substances.