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condition of the soil or subsoil in which the soil grains become cemented together by such bonding agents as iron oxide and calcium carbonate, forming a hard, impervious mass. It is disadvantageous to farming, interfering with the circulation of moisture in the soil and with the growth of roots through the soil. When the condition is caused by the filling of the air spaces in the soil with fine particles of clay, the subsoil is called a clay pan. This usually occurs in acid soil.


An extremely hard soil containing gravel and boulders.




An extremely dense hard layer of soil, boulder clay, or gravel; difficult to excavate.
References in periodicals archive ?
Rototillers fluff up the soil down to about seven inches and then leave you with hardpan beneath.
But when faced with a 300-yard shot at a Kudu across a flat hardpan, my PH literally forced his sticks on me.
Engineered to withstand high stress, the TCT Series is ideal for drilling in soft sandstone or limestone formations, caliche, hardpan and other tough materials.
Active Head Mole piercing tools boasts of a reciprocating head design characterized by a double-strike system that uses the initial impact force to increase production in difficult soils such as cobble, hard clay and hardpan.
Desert and chaparral soils are relatively shallow with no distinct soil profiles (Table 5) due to the presence of hardpan (Specht 1968).
From these sources, Sears concluded that Ohio prairies resulted from successional changes where aquatic habitats decreased as the substrate became drier and plants of prairie communities became established on thick, boulder-free, fine silt soil underlain by a hardpan, with a depth of 100 feet or more to bedrock.
Calcretes (caliche, hardpan, duricrust) are formed mainly in semiarid and arid regions and consist of hard, dense deposits of secondary carbonates that occur as nodules, lumps, crusts, or thick concrete-like layers in the lower soil zone.
Palis & Fischer (1997) found that off-road vehicle use disrupts pond floor microtopography by breaking the hardpan that lies below the pond and causing a shorter hydroperiod, thus decreasing the availability of ephemeral ponds for breeding amphibians.
Most are sandy or contoured, hardpan bottomed with a short supply of slab-rock.