THE VARIETY OF SOILS IN BRITAIN - The Soil - page 24

Britain, and are appropriate for serious survey, teaching and demonstration purposes;
they are unlikely to be popular with landowners if their purpose is merely to satisfy
individual curiosity! Figure 7 sketches a typical pit. Alternatively, for quick examin-
ation of soils from point to point and with minimal disturbance, a screw-thread auger
( Fig. 8 ) is used in professional studies to withdraw successive small depth increments
from all but the driest or stoniest soils. Often, the easiest way to appreciate the lateral
and vertical variations in soils is to study suitable natural or artificial sections. Freshly
exposed by road cuttings, in quarries or on construction sites, these sections can give
a more comprehensive three-dimensional view than any other option does. However,
their occurrence is of course random with respect to soil patterns, or to any partic-
ular interest, rather than being chosen in accord with some statistical or methodical
sampling plan.
F IG. 7
Sketch of a soil profile pit. (From D.F. Ball 1986.)
The repetition of similar horizon sequences in different profiles provides a kind
of bar-code that can be an identifier of a soil class. Using such sequences for clas-
sification, soils of particular profile types can be considered as natural units. These,
whatever their location, are assumed to have had, and usually still have, their soil-
forming ('pedogenic') factors in common. It is this pedological view of soils as nat-