A hardened or cemented soil horizon, or layer The soil material is sandy, loamy, or clayey and is cemented by iron oxide, silica, calcium carbonate, or other substance
a subsurface indurated horizon Red-brown hardpans in Australia are characterised by the presence of a porous matrix, commonly red-brown in colour, cemented by silica (usually hyalite), in a variety of transported or residual host materials
Impervious layer found within the soil It can result from the precipitation of iron, illuviation of clay or the cementing of sand and gravel by calcium carbonate precipitates
Cemented or compacted and often clayey layer in soil that cannot be penetrated by roots. Lime, gypsum, iron, and other minerals may be carried up to the surface of soil by capillary action and deposited to form a natural concrete. In agricultural situations, special equipment may be used to chisel away hardpan so that crop plants can grow
very firm, unyielding ground Especially if there is little grass Example: "You can find a lot of hardpan on hot dry plains courses which often results in tons of roll"
A hard impervious layer composed chiefly of clay or organic materials cemented by relatively insoluble materials, which does not become plastic when wet, and definitely limits the downward movement of water and roots
A hardened soil layer in the lower A or in the B horizon caused by cementation of soil particles with organic matter or with materials such as silica or calcium carbonate The hardness does not change appreciably with changes in moisture content, and pieces of the hard layer do not disintegrate in water