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Soils are regularly exposed to different kinds of external loads,
which can be described as static or dynamic and are always variable in
loading time and magnitude. How far these external forces and soil
management strategies coincide with the approach of sustainability of
soils and their functions in a changing world with an intensely
growing population is often discussed controversially. The most recent
flooding events in Germany, Poland, Austria, Czech Republic, etc. and
the catastrophic landslides in Italy, etc., also visualize the
enormous effects and threats which must be linked to the manmade soil
degradation due to non-site adjusted management approaches in
combination with climate change-induced intensified rainstorm events
etc. This idea becomes even more relevant with increasing intensity of
soil cultivation-induced changes of mechanical, hydraulic and
physicochemical soil processes and functions. The result of such
processes must be defined as a degraded system, which certainly
requires a better and more process based understanding of the dominant
processes under the aspect of requested crop yield increase, better
filtering and buffering for clean drinking water production as well as
also concerning a less intense climate gas emission to the atmosphere
(global change effect).
In the following, various aspects of mainly mechanical soil
degradation will be described in the book elucidating the various
scale effects as well as the consequences also for soil erosion and
its quantification. Eight contributions deal with scale dependent
processes of soil degradation from micro- to macroscale and they also
describe the interactions between soil particles and chemistry on soil
strength.
The rheological approach including the differentiation between various
chemical properties gives a fascinating insight into the soil
processes and properties. On such a basis also the following up
processes of the aggregate level can be better understood and it
certainly also helps to link results with a more complete concept. The
basis for mechanical processes is still the effective stress equation
which in itself can be subdivided in the various scale
effects. Finally both a more complete picture of the strengthening but
also of the degradation processes can be derived and countermeasures
can be developed. These countermeasures also include natural soil
regeneration or amelioration approaches based on the quantified
internal soil strength and the information about the actual mechanical
sensitivity of the soil being threatened by soil compaction and
deformation.
The first paper of Baumgarten and Horn deals with the assessment of
soil degradation by using a scale-spanning soil mechanical approach
followed by Khaydapova et al. who study with the impact of
Anthropogenic Load on rheological properties of typical Chernozems.
The effect of aggregation on soil strength and the risk of soil
degradation for soils derived from volcanic ash is described by
Fuentes et al., while Stumpf et al. define aggregate properties of a
constructed soil in Southern Brazil. How far organic carbon affects
the mechanical strength and biological properties of single aggregates
is defined by Mordhorst et al.
Zink et al. define an approach to quantify subsoil compaction on cable
construction sites while Levy and Mamedov deal with the bulk soil
susceptibility to deformation in different agricultural management
practices and discuss the applicability of water retention curve
patterns. In their contribution Weisskopf et al. describe interesting
results concerning evolution of structural properties of an arable
soil after compaction under different regeneration
pathways. Krummel-bein and Horn finally introduce the circular
characteristics of soil structure formation and degradation and
following implications.
The consequences of non-site adjusted soil management on soil erosion
are the topics of two contributions by Pellegrini et al. about the
assessment of topsoil structure degradation in a compost-amended silty
clay loam soil under simulated rainfall, and by Sarapatka et
al. dealing with arable land degradation with a special focus on water
erosion.
The latter paper leads to the last chapter, where regional soil
degradation studies under various climatic and land use systems are
presented. Gimeno-Garcia et al. describe soil and water salinity in a
coastal wetland in Spain, while Drahorad et al. have analyzed soil
characteristics and nutrient distribution after 27 years of grazing
exclusion in Widou Thiengoly, Senegal. The following two papers again
deal with soil properties in southern America. Dorner et
al. investigate changes in the physical quality of an Andosol under
different management intensities in southern Chile while Kaiser et
al. prepared a review about physical properties in Subtropics and
Tropics.