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Titel |
Spectroscopic characteristics of soil organic matter as a tool to assess soil physical quality in Mediterranean ecosystems |
VerfasserIn |
Lorena Recio Vázquez, Gonzalo Almendros, Heike Knicker, María López-Martín, Pilar Carral, Ana Álvarez |
Konferenz |
EGU General Assembly 2014
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 16 (2014) |
Datensatznummer |
250086576
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Publikation (Nr.) |
EGU/EGU2014-467.pdf |
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Zusammenfassung |
In Mediterranean areas, the loss of soil physical quality is of particular concern
due to the vulnerability of these ecosystems in relation to unfavourable climatic
conditions, which usually lead to soil degradation processes and severe decline of its
functionality. As a result, increasing scientific attention is being paid on the exploration of
soil properties which could be readily used as quality indicators, including organic
matter which, in fact, represents a key factor in the maintenance of soil physical
status.
In this line, the present research tackles the assessment of the quality of several
soils from central Spain with the purpose of identifying the physical properties
most closely correlated with the organic matter, considering not only the quantity
but also the quality of the different C-forms. The studied attributes consist of a
series of physical properties determined in field and laboratory conditions—total
porosity, aggregate stability, available water capacity, air provision, water infiltration
rate and soil hydric saturation—.The bulk organic matter was characterised by
solid-state 13C NMR spectroscopy and the major organic fractions (lipids, free
particulate organic matter, fulvic acids, humic acids and humin) were quantified using
standard procedures. The humic acids were also analysed by visible and infrared
spectroscopies.
The use of multidimensional scaling to classify physical properties in conjunction with
molecular descriptors of soil organic matter, suggested significant correlations between the
two set of variables, which were confirmed with simple and canonical regression models. The
results pointed to two well-defined groups of physical attributes in the studied soils: (i) those
associated with organic matter of predominantly aromatic character (water infiltration
descriptors), and (ii) soil physical variables related to organic matter with marked aliphatic
character, high preservation of the lignin signature and comparatively low degree of
humification (properties involved in the maintenance of physical support, water storage and
air provision functions).
From the practical viewpoint, the results support the idea that the detailed structural study
of the different soil C-forms is useful for accurately monitoring soil physical status. The
quantification of total soil organic carbon ought to be complemented with qualitative analyses
of the organic matter, at least at the spectroscopic level, which can be used for the early
diagnosis of possible degradation processes. Moreover, in already degraded soils, the
knowledge of the sources of variability for each physical property provides valuable
information for the restoration of these ecosystems by adapting inputs of organic matter with
specific features (aliphatic nature, oxidation degree, humification stage, etc.) to particular
soil degradation problems (i.e. soil compaction, waterlogging, water erosion, etc.). |
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