hardpan


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hardpan,

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.
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Hardpan

An extremely hard soil containing gravel and boulders.
Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved

hardpan

[′härd‚pan]
(geology)
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

hardpan

An extremely dense hard layer of soil, boulder clay, or gravel; difficult to excavate.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
References in periodicals archive ?
To determine the intrinsic resistivity for the different terms of the phosphatic series, we carried out, during the geophysical prospection in a parcel of 50 ha,5151 resistivity measurements as horizontal profiling (SYSCAL-R2 resistivity instrument IRIS Instruments) using the wellknown Schlumberger array, in order to map the spatial distribution of the sterile hardpan inclusions.
We attribute the hardpan that developed in some of the pots with [D.sub.W] = S to proliferation of foliage that increased rates of water-uptake to levels sufficient to capture much or all of the ground water being moved upward by capillary action.
In general, the cut areas before and after leveling had higher bulk densities than that of fill areas due to most probably exposure of the subsoil that had higher bulk density than that of the original surface soil, soil compaction by machinery, and arriving to a hardpan. Similar results are valid for the bulk densities of subsurface soil (spatial distribution map of bulk density for subsurface soil was not given in order to save space in the paper).
Shay Church's full-scale elephants and whales derive much of their emotional and political force from the changes the clay undergoes in drying: its deep gloss grows mottled, then dusty; it cracks and scales like hardpan desert against its supporting armature.
Testing of the main main magnetic anomaly was prevented by a siliceous hardpan. Anomalous results (4m at 1230 ppm Zn, 209 ppm Cu and 0.3 g/t Au) were returned from 40m depth from a weathered siltstone adjacent to the main magnetic anomaly which remains untested and is a target for follow up RC drilling.
Moreover, frequent plowing led to the formation of hardpan at the plow depths, decreases water infiltration with accelerated soil erosion (Alakukku et al., 2003).
It showed 54% increase in plant height over conventional tillage might be due to deep tillage that resulted in break down of hardpan which facilitates root proliferation; more nutrients were available to plants.
A boy, me, waits for his birthday guests, bouncing a half-inflated ball on the hardpan. His eyes show the dawning conviction that no one is coming.
When small lakes dry up, they leave a salt crust or hardpan. The flat area of clay, silt, or sand encrusted with salt that forms is known as a playa or a sink.
Rototillers fluff up the soil down to about seven inches and then leave you with hardpan beneath.
In addition, the gravel content and hardpan appeared to be barriers to deeper root development, so the roots may not have reached the soil water.
But when faced with a 300-yard shot at a Kudu across a flat hardpan, my PH literally forced his sticks on me.