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| Titel |
Soil Infrastructure, Interfaces & Translocation Processes in Inner Space ("Soil-it-is"): towards a road map for the constraints and crossroads of soil architecture and biophysical processes |
| VerfasserIn |
L. W. Jonge, P. Moldrup, P. Schjønning |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 13, no. 8 ; Nr. 13, no. 8 (2009-08-19), S.1485-1502 |
| Datensatznummer |
250011971
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| Publikation (Nr.) |
 copernicus.org/hess-13-1485-2009.pdf |
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| Zusammenfassung |
| Soil functions and their impact on health, economy, and the environment are
evident at the macro scale but determined at the micro scale, based on
interactions between soil micro-architecture and the transport and
transformation processes occurring in the soil infrastructure comprising
pore and particle networks and at their interfaces. Soil structure formation
and its resilience to disturbance are highly dynamic features affected by
management (energy input), moisture (matric potential), and solids
composition and complexation (organic matter and clay interactions). In this
paper we review and put into perspective preliminary results of the newly
started research program "Soil-it-is" on functional soil architecture. To
identify and quantify biophysical constraints on soil structure changes and
resilience, we claim that new approaches are needed to better interpret
processes and parameters measured at the bulk soil scale and their links to
the seemingly chaotic soil inner space behavior at the micro scale. As a
first step, we revisit the soil matrix (solids phase) and pore system (water
and air phases), constituting the complementary and interactive networks of
soil infrastructure. For a field-pair with contrasting soil management, we
suggest new ways of data analysis on measured soil-gas transport parameters
at different moisture conditions to evaluate controls of soil matrix and
pore network formation. Results imply that some soils form sponge-like pore
networks (mostly healthy soils in terms of agricultural and environmental
functions), while other soils form pipe-like structures (agriculturally
poorly functioning soils), with the difference related to both complexation
of organic matter and degradation of soil structure. The recently presented
Dexter et al. (2008) threshold (ratio of clay to organic carbon of 10 kg kg−1)
is found to be a promising constraint for a soil's ability to
maintain or regenerate functional structure. Next, we show the Dexter et al.
(2008) threshold may also apply to hydrological and physical-chemical
interface phenomena including soil-water repellency and sorption of volatile
organic vapors (gas-water-solids interfaces) as well as polycyclic aromatic
hydrocarbons (water-solids interfaces). However, data for
differently-managed soils imply that energy input, soil-moisture status, and
vegetation (quality of eluded organic matter) may be equally important
constraints together with the complexation and degradation of organic carbon
in deciding functional soil architecture and interface processes. Finally,
we envision a road map to soil inner space where we search for the main
controls of particle and pore network changes and structure build-up and
resilience at each crossroad of biophysical parameters, where, for example,
complexation between organic matter and clay, and moisture-induced changes
from hydrophilic to hydrophobic surface conditions can play a role. We
hypothesize that each crossroad (e.g. between organic carbon/clay ratio and
matric potential) may control how soil self-organization will manifest
itself at a given time as affected by gradients in energy and moisture from
soil use and climate. The road map may serve as inspiration for renewed and
multi-disciplinary focus on functional soil architecture. |
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