Geoscience Reference
In-Depth Information
Figure 5-5.
Hardwood tree trunks exposed by recent
l ood erosion in Holocene alluvial gravel of
southwestern Poland. Photo by J.S. Aber.
Figure 5-3.
Olpe Soil is a compound upland soil (see
Color Plate 5-3). The lower portion (C) is a paleosol
developed in highly weathered (leached and oxidized),
older (Neogene), alluvial gravel. The upper part (A &
B) is composed of younger (Holocene) loess. Scale
pole marked in feet (30-cm intervals). Flint Hills,
Kansas, United States. Photo by J.S. Aber.
Figure 5-6.
Standing water saturates the soil
throughout the year in this Florida cypress swamp.
Photo courtesy of P. Johnston.
By the 1930s, however, doubts began to
appear about converting wetlands to other land
uses. Kenney and McAtee (1938) noted two
issues. Firstly they questioned the economic
advantages of converting wetlands into crop-
lands, and secondly they pointed out the eco-
logical consequences of widespread wetland
drainage, particularly the detrimental impacts
on populations of waterfowl and fur-bearing
animals. Nevertheless, the continued and rising
demand for food production across the develop-
ing world has meant an unrelenting push for
wetlands and forested areas to be brought under
agricultural production.
Figure 5-4.
Till exposed in a coastal cliff at Galway,
western Ireland. Also known as boulder-clay, till is
an unsorted, unstratii ed mixture of anything and
everything over which the glacier moved prior to
deposition. Pocket knife for scale; photo by J.S. Aber.
