Geoscience Reference
In-Depth Information
earth
s surface as well as the gas exchange between terrestrial and atmospheric
systems. Soils are also a biological habitat and gene reserve, supporting a large
variety of organisms. Soils contain more species in number and quantity than all
aboveground ecosystems. Therefore, soils are a main basis of biodiversity. Soils are
also the physical basis for technical, industrial and socio-economic structures and
their development. Independent of all aforementioned functions, soils are a source
of raw materials, e.g. of clay, sand, gravel and minerals in general, as well as a
source of geogenic energy and water. Furthermore, soils are a cultural heritage,
protecting valuable paleontological and archaeological remnants. 19 The roles soils
are expected to play for humans often exclude one another, leading to con
'
icts
about land-use such as those encountered between nature protection and infra-
structure development or quarrying.
Next to human-induced erosion and salinization, nutrient depletion is the most
prevalent damage to soil ecosystems in
icted by humans. 20 Commonly, all these
. 21
processes are subsumed as
'
soil degradation
'
In the UNCCD de
nition, degra-
dation is de
reduction or loss of the biological or economic productivity
and complexity of rain fed cropland, irrigated cropland, or range, pasture, forest and
woodlands resulting from land uses or from a process or combination of processes,
including processes arising from human activities and habitation patterns, such as:
(i) soil erosion caused by wind and/or water, (ii) deterioration of the physical,
chemical and biological or economic properties of soil; and (iii) long-term loss of
natural vegetation
ned as
. 22
Land-use resulting in the covering of soils with concrete and other materials to
use them for infrastructural purposes is a further major threat to soils, particularly
close to urban agglomerations. It is important to keep in mind that soils like all
ecosystems, are dynamic entities. Soils can be changed through management-
induced or through natural processes.
3.2.2.1 Erosion
Apart from impairments of soil quality, the mobility of soil as such is an important
issue. A term often used for soil mobility is
. Erosion is a natural process
which shapes the earth in an interplay with other processes such as volcanism and
tectonics. Through the action of water and wind, mountains are reduced to sand,
and within geological times, sediments undergo metamorphosis and uplift and end
as sandstone mountains, beginning the cycle anew. Erosion can bene
'
erosion
'
t agriculture,
as its result, alluvial deposits or aeolian sediments such as loess are prime land for
19 Blum ( 2008 ).
20 Compare particulary Sect. 5.2 in Koehler ( 2005 ).
21
Lysenko ( 2004 ).
22
Section 1.2 in: Juergens ( 2006 ).
Search WWH ::




Custom Search